Biology 2200 Final Flashcards

• Pre-300 BCE
• Aristotle describes species as fixed
• scale of nature arranges species in order of lower to higher complexity

• 1785
• proposes gradualism
• earth is shaped by small slow changes

• 1798
• publishes "essay on the principle of population"
• human population growth is limited by resources

• 1809
• proposes organisms change due to the environment
• species drives towards increased complexity
• traits that are used improve and are inherited by offspring

• 5 generations of rat breeding, cut off their tails and then bred
• no offspring had short tails

• 1812
• publishes studies on fossils
• fossils as evidence of extinction

• processes that shape the earth have been uniform over time
• published principles of geology

• 1831-1836, voyage of the beagle
• 1844, writes his essay of decent with modification
• observations of geology, fossils, plants and animals led Darwin to think about how species arise

• 1858, sends Darwin his hypothesis of natural selection
• proposes evolution via natural selection

• decent with modification
• species diversity due to branching from common ancestor in response to environment
• describes natural selection as the mechanism for evolution

• many offspring are produced, not all survive
• traits vary among individuals within a population and may be heritable
• some heritable traits hive individuals an advantage in their environment
• advantageous traits, conferring higher fitness, become more common

individuals experience selection; but population evolve

• evolution is a change in the heritable traits of a population from generation to generation
• natural selection is a mechanism of evolution

• small, drab fish found in coastal waters or inland lakes in the northern hemisphere
• a model system for study evolution and speciation:

- variation in morphology

- recent changes in environment

• stickles have different phenotypes in marine and freshwater environments
• lateral plates vary between individuals within populations
• traits is heritable
• spines and lateral plates protect against predators

Producing lateral plates is costly

• lakes havee lower ion concentrations
• fish with reduced lateral plates in lakes: grow larger, have higher overwinter survival, breed sooner

• animals with mammals-like trait appear 300 MYA
• true mammals appear 200-145 MYA
• co-occurred with dinosaurs
• 3 major lineages arose 140 MYA
• adaptive radiation at the end of cretaceous

• similarity die to common ancestry
• anatomical, molecular
• form and function may be very different

similarity of form/function due to similar environments

• a genotype that produces different phenotypes in response to the environment
• not heritable

• difference among individuals in the composition of their genes or DNA sequences
• does not always lead to phenotypic differences
• not all phenotypic differences indicate genetic variation

• point mutations
• chromosomal mutations
• crossing over during meiosis

• observed 3:1 patterns of inheritance of phenotypic traits
• two alleles at a locus: dominant (determines phenotype) and recessive (masked in phenotype)

groups of individuals of the same species that live in the same area and interbreed, leaving viable offspring

different variants of a gene

all copies of all alleles at every locus in all members of the population

change in the gene frequencies of a population from generation to generation

• if alleles are transmitted by meiosis and random mating, frequencies do not change over time
• frequencies of alleles A1 and A2 is given by p and q

p + q =1

p^2 + 2pq + q^2 = 1

1. no selection

2. no mutation

3. no migration

4. large population

5. random mating

• shows the frequencies of alleles in genotypes IN THE ABSENCE of evolution
• deviation from H-W equilibrium indicates one of the assumptions has been violated

measured from population

calculated from observed data

predicted frequency of genotypes IF population is in H-W equilibrium

tested with statistics

• mutation
• gene flow
• natural selection
• genetic drift

natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals

natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes

natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes

• change in allele frequency due to chance
• has a larger effect on smaller population
• can cause random change sin allele frequencies
• can cause alleles to become fixed

Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population.

• small number of individuals establish a new population
• daughter populations have lower genetic diversity than source populations

selection within a sex to compete for mates

selection by one sex for mates; mate choice

heterozygotes have greater fitness than either homozygotes

• fitness depends on how common the phenotype is in the populatin

benefits:

• remain active in spite of poor environmental
• efficient to have optimized enzymes
• efficient to have optimized enzymes

costs:

• expend A LOT energy to maintain temperature

groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups

• local variation
• asexual reproducers
• hybrids

habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, gametic isolation

species mate in different places

species mate at different times

unique behaviors attract different species

morphological differences prevent mating

sperm cannot fertilize eggs

reduced hybrid viability, reduced hybrid fertility, hybrid breakdown,

hybrids do not live to maturity

hybrids do not produce viable offspring

offspring viability is reduced after several generations

Occurs when you have an interbreeding population and something happens to physically separate the mates
- populations are geographically isolated from one another
geographic separation -> selection and/or drift -> speciation

The formation of new species in populations that live in the same geographic area
polymorphism appears -> assortative mating

• cell division error within a species leads to increase in chromosome number
• in a diploid, error leads to diploid gametes and tetraploid species
• new species likely established through self-fertilization

• hybridization between species, chromosomes can't pair up
• error doubles chromosomes, hybrids can now interbreed
• new species likely established through self-fertilization

• polyploidy is an incredibly successful speciation mechanism in plants:

it happens nearly instantaneously, it provides higher genetic diversity, it leads to reduced interbreeding depression

selection due to environment leads to increased frequency of phenotype over time

physiological response to environment to change in individual phenotype

species exhibit phenotypes that differ due to local conditions (could lead to speciation over time)

when reproductive isolation between two species breaks down

reinforcement

• individuals that hybridize have fewer offspring
• reproductive isolation increases

fusion

• individual that hybridize have an equal number or more offspring
• reproductive isolation decreases

stability

• hybridization limited
• small hybrid zones or variable conditions
• hybrid production continues

reproductive isolation

natural selection, genetic drift, and muutataion

gene flow

- came about in the 70s
- a rapid shift in phenotype that would be sustained overtime

- traditional view of speciation
- we would see a small change that would lead to mutation then a shift in some of the population's phenotype with eventual speciation

A species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change.

4.6 Billion years old

535-525 MYA

1.2 BYA

1.8 BYA

3.5 BYA

4.6 BYA

• 4.6-3.85 BYA
• differentiation of earth into mantle, crust, core
• formation of the atmosphere from volcanic gasses
• water vapor condensed to acidic lakes
• no evidence of life on earth

• more secure info retention
• connections in cerebral cortex

• 3.85 - 2.5 BYA
• earliest conclusive evidence of prokaryotes about 3.5 BYA
• recent study reports fossils from 3.77 BYA
• appearance of photosynthesis before 2.7 BYA
• O2 producing prokaryotes (cyanobacteria)
• O2 initially dissolves in water
• when water is saturated, OO2 increases in atmosphere

• mats of cyanobacteria living on sea surface covered with sediment
• new cells grow on layers of old cells, old layers fossilize
• date to 3.5 BYA, but there are living examples

• sharp rise in atmospheric O2 about 2.5 BYA
• fragmentary fossil record (organisms are small, soft-bodied)
• first eukaryote about 1.8 BYA (cells with nuclear envelopes, organelles)
• first multicellular eukaryotes about 1.2 BYA

• endosymbiosis first proposed in 1960s, but highly controversial
• now strongly supported by data
• key innovation leading to eukaryotes

mitochondria and chloroplasts have:

• outer membrane similar to eukaryotic plasma membrane
• inner membrane similar to bacterial precursor

Mitochondria, chloroplasts, and bacteria:

• divide by binary fission
• have smaller ribosomes than eukaryotes
• have circular DNA (usually)
• have genomic similarities that suggest close relationships

done through segregation of function, much more efficient

• first major diversification 670-550 MYA: Ediacaran biota - the oldest macroscopic eukaryotes

• multicellularity evolved in the Proterozoic eon
• extensive radiation occurred int he Cambrian period (phanerozoic eon)
• most extant phyla appear in this period

500 MYA

470 MYA

450 MYA

425 MYA

365 MYA

5

• current rates of extinction are 100-1000x higher than the background extinction rate
• more than 99% of modern extinction due to human activity (defaunation, habitat loss, climate change)
• predicted to reach 6th mass extinction in 240-540 years

major diversification events can happen globally or locally

• changes int he environment
• availability of new habitat
• new innovations in morphology, development or behavior
• new species interactions

• rise in O2 levels
• receding glaciers
• appearance of diverse body plans
• emergence of predators

reciprocal evolution of 2 interacting species

• each species responds to selection from the other
• leads to diversification within groups

interacting species must repeatedly adapt to each other to maintain their relationship

high levels of genetic diversity

changes in allele frequency from generation to generation in a population

broad patterns of evolution above the species level

a visual hypothesis of the evolutionary history of a group of species, populations or genes

relatedness

trait originated from the ancestor of the taxon

trait is an evolutionary novelty to the clade

trait is shred by all clade members

similar environment pressure can lead to similar adaption in different organism s

• using clades to build a phylogenetic tree
• grouping taxa based on shared ancestry
• smaller clades are nested in larger clades

an ancestor and all of its descendants

an ancestor but only some of its descendants

group does not include most recent common ancestor

• clades are groups of taxa with a common ancestor and shared derived characteristics
• phylogenetic trees are built using a nested clade approach
• poly- or paraphyletic groups provide incomplete (or misleading) information about evolutionary relationships

1. select the evidence you will use o group the taxa
2. collect data: measure characters of your taxa
3. organize data into a character matrix
4. draw a tree

• find the simplest explanation
• the fewest evolutionary events

• genes found in different species with a common ancestor
• genes diverge after speciation

• gene duplication within a species
• more than one copy, genes diverge over time

the variability among living organisms from all sources and the ecological complexes of which they are part; includes diversity within and among species

• to understand the evolution of life
• to appreciate nature
• to assess its economic value
• to see the larger impact of human on the earth

1. cell wall: bacteria - peptidoglycan and archaea - polysaccharides, proteins
2. fimbriae and capsule: stick to capsule
3. pili: pulls cells together for conjugation
4. flagella: mobility

Aerobic prokaryotes: respiratory membrane (like mitochondria)

photosynthetic prokaryotes: thylakoid membrane (like chloroplasts)

chromosomes (circular contain less DNA than eukaryotes)

plasmids (small rings of DNA that replicate independently

form in response to hostile conditions; dormant until conditions improve

mutation and recombination

*Reproduction by binary fission does not lead to diversity

• foreign DNA from the environment transported into cells
• proteins recognize DNA from closely related species

• phage (virus) infect bacteria
• phage replicates it DNA within host cell
• as new phages form, may gain fragments of donor cell DNA
• phage carriers fragmented DNA from donor to recipient cell
• crossing over leads to recombination of DNA

1. one strand of F+ cell plasmid DNA break at arrowhead
2. broken strand peels off and enters F- cell
3. donor and recipient cells synthesize complementary DNA strands
4. recipient cell is now a recombinant F+ cell

• short generation times -> accumulation of mutations -> opportunity for selection
• horizontal gene transfer -> recombination between different species -> novel genes
• plasmids -> mobile DNA with high genetic variation -> useful for adapting to new environments

• overuse, misuse, exposure led to resistance
• rapid evolution due to short generation times
• once resistant genes have emerged, can be widely transferred via plasmids

decomposers

• heterotrophic bacteria
• break down dead organic material

Oxygen production

• autotrophic cyanobacteria
• photosynthesis

Nitrogen Fixation

• cyanobacteria, methanogens (archaea)
• atmospheric nitrogen (N2) -> useable nitrogen (NH3)

skin, nervous system

get their energy from chemicals

use inorganic carbon (CO2)

use organic carbon (glucose)

can use different sources of energy and carbon

• diverse protection and support structures:

flexible cell walls and cytoskeletons for mobility, and rigid cell walls or shells for protection

• nuclear envelope:

likely formed from infolding of plasma membrane, and separate transcription and translation

• endosymbiosis
• multicellularity

red and green algae

secondary led to other photosynthetic protists

• chloroplasts have 3-4 membranes
• photosynthetic pigments shared by lands plants and distantly related protists
• nucleus now vestigial

• live in many different habitats
• acquire resources in different ways
• different mobility strategies
• different cell surfaces

plasmodium

• cause malaria
• multiple hosts
• live mainly inside host cells

Tryanosomes

• chaga's disease
• multiple hosts
• prevent host immunity with protein switches

food sources:

red algae

• agar, nori, dulse
• marine seaweed
• mostly multicellular

Plant pathogens

water molds

• pathogens and parasites
• economic impact
• phytophthora infestans caused potato famine

green algae

• freshwater and marine
• unicellular, filamentous multicellular

diatoms

• freshwater and marine
• unique cell walls with silicon dioxide
• after blooms, bodies sink to ocean floor, sequesters carbon
• promoting blooms may reduce CO2

Slime Molds

• terrestrial
• unicellular with thousands of nuclei
• break down dead plants

Brown algae

• multicellular marine seaweed (kelp)
• home to sea otters, fish and diverse marine invertebrates
• loss of sea otters caused trophic cascade in kelp forests

dinoflagellates

• freshwater and marine
• bloom cause toxic red tides
• deplete oxygen
• can lead to fish kills

charophytes (green algae)

• prevent water loss

waxy cuticle, stomata and desiccation-resistant spores

• UV protection

flavonoids to provide "sunscreen"

• access nutrients efficiently

mycorrhizae

470 MYA

non-vascular

• lack specialized cells to transport water and nutrients
• this limits height/size
• also lack roots (rhizoids as anchors)
• gametophytes are dominant life stage
• gametangia can be male/female/bisexual
• sperm travel through water
• sporophytes can't live independently (attached to gametophyte, which supplies water/nutrients
• millions of spores (dispersed by wind)

• peat
• antibiotic properties
• stores 30% of the world's carbon
• harvested for fuel
• anoxic conditions can preserve tissue

425 MYA

• a larger, more complex sporophytes generation
• a sporophyte that is independent of the gametophyte
• resources transported through vascular system
• roots and leaves
• increased growth die to vascularization

xylem, phloem, and lignin

• water conducting cells
• lignin in cell walls

distributes sugars, amino acids, products synthesized by the plant

• structural support
• helps plants grow tall!

roots

• absorb water and nutrients from soild

leaves

• increased photosynthesis

spores

homosporous; bisexual gametophytes have organs to make sperm and eggs

heterosporous; male gametophytes have organs to make sperm and female gametophytes have organs to make eggs

• seedless vascular plant
• club moss, spike moss
• most ancient rooted lineage
• were tree-sized during carboniferous

• seedless vascular plant
• ferns very speciose and common in moist humid habitats
• horsetail and whisk fern are "living fossils"
• whisk fern has branching stem, no leaves

• in the carboniferous (360-300 MYA), giant seedless vascular plants converted CO2 to organic carbon, then died
• microbes that could break down cellulose and lignin had not yet evolved
• tree did not fully decay, turned into coal
• 90% of coal burned today formed

seeds

• embryos with food supplies and a protective coat
• disperse long distances and survive harsh conditions

Pollen

• male gametophytes surrounded by pollen wall
• does not require water to travel to female gametophyte

1 megaspore (female gametophyte)

makes many microspores (male gametophyte)

yes, but they do not all have seeds and pollen

• conifers are the most speciose gymnosperms
• generally evergreen
• small or needle-like leaves
• some of the largest and oldest organism on earth

• gymnosperms
• 300 million years old
• only gymnosperms with compound leaves

• gymnosperm
• only 1 extant species
• males plants ornamentally (Seeds smell rancid when decaying)

• gymnosperm
• closely related angiosperms
• welwitschia only lives in namib desert, plants can be up to 2000 years old

360 MYA

in the carboniferous, 360-300 MYA

in the Permian, 300-250 MYA

in the mid-cretaceous, 145-65 MYA

• flowers

specialized shoots with up 4 types of modified leaves: sepals, petals, stamens, carpels

provide more species-specific breeding systems

• fruits

ovules housed within the ovary

as seeds develop, ovary walls thicken

ovary matures into a fruit (protects seeds, aids in dispersal, fleshy or dry)

• microspores become male gametophytes with 2 cells (generative cells forms 2 sperm, tube cell forms pollen tube)
• megaspore becomes female gametophyte with about 7 cells
• double fertilization

2 sperm released in ovule, 1 sperm fertilizes egg, 1 sperm nuclei fuses with 2 nuclei in embryo sac -> endosperm (3n)

• emergence of flowers and fruit led to stunning diversity of interactions
• pollination

movement of pollen by animals increases likelihood of mating

• seed dispersal

movement of embryos by animals increase range and habitat diversity

• color scent serves as long-distance signals
• pollinator visit flowers to collect nectar and pollen
• floral traits have co-evolved with different pollinators

• approximately 370,000 species
• 4 lineages: basal angiosperms, magnoliids, monocots, eudicots

• 60,000 species
• floral organs usually found in multiples of 3
• plants include: grasses, orchid, palms

• 280,000 species
• pollen grains have 3 openings
• plant include: legumes, common ornamental flower, fruit trees, cacti

• unicellular or multicellular
• not motile
• heterotrophs
• absorb food from the environment
• secrete hydrolytic enzymes to break down food
• can consume living or dead

• multicellularity fungi us hyphae for growth and nutrient Acquistion
• cell walls strengthened by chitin
• hyphae form mycelium: belowground - nutrients and aboveground - reproduction

• fungi can have both sexual and asexual reproduction
• formation of diploid zygote is a multi-step process
• clonal reproduction through budding and spores

• more closely related to animals than plants
• heterotroph
• chitin to strengthen cell walls
• store carbohydrates a glycogen
• DNA evidence
• diverged 1-1.5 BYA
• multicellularity evolved independently in fungi and animals

• symbiotic relationship between fungi and 90% of plant species
• fungi increase nutrient uptake for plants
• plants provide fungi with carbohydrates

decomposer

• break down cellulose

endophytes

• increase defense or stress tolerance

mutualisms

• fungus-farming ants
• lichens

plant pathogens

• rust, smut, blights
• ecological and economic impact

Animal pathogens

• chytrid fungus and amphibians
• Ophiocordyceps and ants

• multicellular eukaryotes without cell walls
• proteins outside cell membrane provide structural support, cell-cell adhesion and communication
• heterotrophs that ingest their food
• mobile
• nerves and muscles

• patterns of development
• body plan (symmetry, tissue, body cavities)

• 2 haploid gametes produced by meiosis from diploid zygote
• zygote undergoes mitotic division (cleavage)
• blastula: multicellular stage, hollow ball of cells
• gastrulation: one end of embryos folds inward, fills blastocoel, producing layers of embryonic tissue, outer layer = ectoderm, inner layer = endotherm
• "pouch" called archenteron
• opening called blastospore

during gastrulation

skin, nervous system

digestive tract

circulatory system, muscle, bone, organs

cleavage

• cell divides diagonally
• goes through spiral cleavage
• determinate development

coelom formation

• solid mesoderm masses that split and form coelom

fate of blastospore

• mouths develop from blastospore
• first pore is turned into the mouth

cleavage

• cells divide linearly
• go through radial cleavage
• indeterminate development

coelom formation

• Fold of archenteron fold in and form coelom

fate of blastophore

• anus develops from blastospore
• first pore is turned into the anus

about 710 MYA

choanoflagellates

450 MYA

365 MYA

2522-66 MYA

66 MYA - present

• sensory organs
• modes of feeding
• modes of movement
• reproductive strategies

• have a body cavity
• lined on both sides with tissue (specifically mesoderm)

• do not have a body cavity
• do not have organs

• have a body cavity
• structured differently
• lined only on one side with mesoderm

• asymmetric
• sessile as adults
• lack true tissue
• gas exchange/waste removal by diffusion
• filter feeders
• closely related to choanoflagellates

• radially symmetric
• 2 germ layers
• sac with central digestive compartment
• 2 phenotypes: polyps and medusas
• can have sexual and asexual life stages, which alternate

a clade defined by DNA

• protostomes
• 3 germ layers
• body cavities vary
• some have lophophores, ciliated tentacles for feeding
• some have trochophore larva

• dorsoventrally flattened bodies
• acoelomate
• metabolic processes by diffusion
• most have a gastrovascular cavity with only one opening
• no circulatory system
• can be free-living or parasitic

• coelomates
• aquatic, most terrestrial habitats
• range from 1mm-3m
• earthworms (tilla and aerate soil, decomposers)

• over 100,000 species
• marine, freshwater or terrestrial
• soft-bodied, most have calcium carbonate shell
• coelomates
• most have separate sexes (some hermaphrodites)

secretes shell

contains internal organs

locomotion

for feeding (is not in all molluscs)

• terrestrial or aquatic
• radula can graze, scrape, chew
• most have a single spiral shell
• head with eyes in tentacles

• aquatic filter feeders (gills in mantle cavity)
• no distinct head, no radula, some have eyes
• most sedentary

• marine hunters
• well-developed sensory organs
• jet propulsion by water expelled from mantle cavity
• shell reduced/internal
• closed circulatory system

• paired jointed appendages
• exoskeleton: chitin +protein/calcium carbonate (grow by molting)
• well-developed sensory organs (eyes, olfactory receptors, antennae)
• coelomates with reduced coelom (main body cavity is the hemocoel)
• open circulatory system (hemolymph pumped through hemocoel)
• gas exchange (aquatic species have gills, terrestrial species have trachea)

spiders and ticks (chelicerates)

• predators and parasites
• 6 pair appendages (8 legs)

Myriapods (many feet)

• millipedes -> 2 pairs legs/segments
• centipedes -> 1 pair legs/segments

Crustaceans

• specialized appendages
• exoskeleton of calcium carbonate

• 6 legs
• flight (not all groups)
• metamorphosis

incomplete: young resemble adults, smaller, wingless

complete: larvae distinct in phenotype, diet, habitat from adults

• sexual reproduction is common
• some insects have asexual reproduction

most insects can fly, but wings vary in shape, size, and number

flight increases: dispersal, foraging, mating

diverse mouthparts increase access to different food types

pollinators

• insect pollinators are critical for producing fruits and vegetables
• annual value is >$2200 billion US

Pest Controllers

• predatory and parasitic insects can control herbivores in crops

Decomposers

• nutrient cycling

voracious herbivores

• insect pests can decimate crops
• increased resistance to pesticides

Vectors of disease

• mosquitoes -> malaria, zika, yellow fever, west nile, chikungunya
• kissing bugs -> chagas disease
• tstese flies -> african sleeping sickness

• invertebrate deuterostomes
• larvae have clear bilateral symmetry

notochords, dorsal hollow nerve chord, pharyngal cleft and slits, muscular post anal tail

• present in all chordate embryos, some adults
• longitudinal, flexible rod between digestive tube and nerve cord
• derived from mesoderm
• provides skeletal support

• hollo tube that develops into the central nervous system
• derived from ectoderm

• in non-chordates, digestive tract runs body length
• reduced in some adult chordates

• arches along pharynx develop into slits that open into the pharynx
• invertebrates -> suspension feeding
• aquatic vertebrates -> gills
• tetrapods -> no slits (arches become part of ears, head, and back)

Lancelets ad tunicates

• notochord protects dorsal hallow nerve cord
• filter feed using pharyngeal slits

• larvae reflect chordate characters
• adults lose characters after metamorphosis
• siphons used for filter feeding , waste removal

vertebrate

• cartilaginous or bony

Developed nervous system

• cranium protecting brain
• spinal cord

63,000 vertebrates species

• transitional fossils from 530 MYA
• earliest vertebrates 500 MYA
• mineralization

started with teeth like structures

• earliest gnathostomes (jawed vertebrates) from 440 MYA

• jawless, no backbone
• rudimentary vertebrate
• notochord persists in adults

hagfish

• reduced sensory structures
• produces slime as defense

Lampreys

• cartilaginous teeth lack collagen
• adults parasitize fish

• rapid radiation of jawed fish after jaws appear
• hypothesis: jaws originated from the skeletal rods that support gill slits
• jaws and rods have similar morphology
• both jaws and rods derived form the same cells in the embryo (other skeletal elements are not)
• no fossil evidence to corroborate

• skeleton of cartilage (derived trait)
• mineralized teeth
• streamlined bodies for hunting

sharp vision, olfactory bulbs, can detect fields of animals

• swim nearly continuously

keep from sinking, gas exchange

• over 27,000 extant species
• bony fish with rays in fins
• gills for gas exchange
• swim bladder maintains buoyancy (derived from lungs)
• lateral lines - detects pressure/vibrations

• thought extinct, found alive in 1938
• bone in fins that resemble

• breathe air but also have gills
• fleshy fins, walk short distances under water
• closest living to tetrapods

• long-limbed bones
• more derived wrist bones
• large pelvis, making it a strong swimmer, able to walk on sea floor
• no strong connection between pelvis and spine, did not live on land

• a new way to move
• increased skeletal support
• new gas exchanges support
• strategies to prevent water loss

365 MYA

• limbs with digits
• head separated from body via neck
• bones of pelvic girdle fused to backbone
• adults lack gills

• larvae aquatic

metamorphosis leads to legs, lungs, more complex organs

• moist skin facilitates gas exchange

some species lack lungs altogether

• external fertilization in water or moist environments

eggs lack shell

• 550 species
• some entirely aquatic, some terrestrial as adults, some fully terrestrial
• some terrestrial species lack lungs
• capable of limb regeneration
• 10% of global salamander diversity found in Appalachians

• >7,000 species
• aquatic larvae distinct from adults
• hop instead of walk
• toads are warty frogs, but not monophyletic
• males vocalize to attract mates or defend territory
• some produce deadly toxins advertised with bright colors

allantois, chorion, amnion, yolk sac

metabolic waste

gas exchange

fluid-filled cavity protects embryo

holds nutrients

• amniotic egg
• eggs with shells or internal gestation

reduces water loss of developing embryo

• less permeable skin

reduced water loss of adults

• rib cage used for ventilation

efficient gas exchange

• earliest reptiles 310 MYA
• dinosaurs originated around 245 MYA
• dominant animals for 135 MY
• all non-avian species extinct 66 MYA

• scales/feather containing keratin

prevent desiccation

• lay shelled eggs on land

internal fertilization prior to shell secretion

• snake/lizards are ectotherms

regulate temperature with behavior

• birds are endotherms

internal temperature regulation

• 307 species
• upper and lower shells fused to vertebrate, collarbones and ribs
• found in many different habitats: on land, in ponds, rivers, oceans
• divided into two groups based on neck retraction

• from a few cm to >3m
• territorial (habitat, food, mates)

• lizards -> snakes (leg lost)
• ancestors were burrowing or aquatic lizards
• carnivores with adaptions for hunting and capturing prey

• 10,000 species
• modification for flight
• evolved from dinosaurs 160 MYA
• extant species emerged 66 MYA
• live in divers habitats and lifestyles

large brain, more acute senses than other reptiles and amphibians

wings for dispersal

beak morphology - diet breadth

honeycombed bones, reduced organs (no bladder, 1 ovary, small gonads), no teeth, feathers, large pectoral muscles

mammary glands, hair, fat layer under skin, endotherms, larger brains, extended parental care, diverse teeth

• animals with mammals-like trait appear 300 MYA
• true mammals appear 200-145 MYA
• co-occurred with dinosaurs
• 3 major lineages arose 140 MYA
• adaptive radiation at the end of cretaceous

• platypus and echidna
• lay egg
• have mammary glands but lack nipples

• opossums, kangaroos, koalas
• early development in uterus includes a placenta
• complete embryonic development outside uterus while nursing

• more complex placentas
• development completely in uterus
• lack epipubic bone - allows expansion of abdomen during pregnancy
• divergence of groups fuzzy (between 100-60 MYA)

• 2277 species (40% mammals)
• continuously growing incisors in both jaws
• live on land, in trees, underground, in water
• keystone species in many ecosystems

soil aeration and nutrient distribution and hydrology

• human disease vectors

• split into odd toed and even toed
• hooves made of keratin
• herbivores and omnivores
• diverse cranial appendages
• domesticated for food, clothing, transportation

• 89 species found in freshwater and marine habitats
• originated from land mammals

(sister taxa to hippos)

• forelimbs are flippers, hindlimbs are vestigial
• 2 sub orders: toothed, baleen
• intelligent, social animal s

• 280 species
• split into feliforma, "cat-like" and caniforma, "dog-like"
• sharp teeth and claws
• mostly terrestrial (except walruses and seals)
• skull shape associated with predatory lifestyle (some herbivore)

• 190-448 species depending on classification system
• arose 85-55 million years
• name means "first-ranked"

Linnaeus saw primates as the highest order of animals

• hands and feet adapted for grasping
• flat nails instead claws
• large brains, short jaws
• eye look - hand/eye coordination
• flexible or opposable thumb (monkeys/apes)

• apes diverged from old world monkey 25-30 MYA
• non-human apes now found only in old world tropics

• upright and bipedal
• larger brain, complex thought, tool use
• reduced jawbones and teeth
• shorter digestive tract

• lighter skeletons
• "modern" skull is thin-walled with a vertical forehead
• smaller teeth
• hunting and fishing with specialized tools
• developed sophisticated societies and cultural practices

• originate from Afica aboout 200,000 years ago
• migrated to middle east
• from middle eat to europe, asia, australia
• from asia to the americas

early homo sapiens coexisted with other homo species

• interbreeding occured between several groups

changes in lifestyle around 50,000 years ago

• more advanced tools
• elaborate shelter
• social, cultural development

heterozygosity within a population

species richness and abundance

interactions between species and environment

• nature for nature's sake
• inspires art, poetry
• tied to spirituality
• enjoyed and appreciated in many ways

• biodiversity is correlated with ecosystem

primary production, nutrient cycling

• supports diversity at higher trophic levels

more plants = more herbivores = more predators

functions provided by nature that support humans

• products extracted from ecosystems
• processes that maintain healthy ecosystems
• cultural benefits from ecosystems

• estimating the monetary value of ecosystem services can be easy or difficult

easy: value of lumber harvested from a forest

difficult: aesthetic of a forest

• many species contribute to multiple ecosystem services

$33-125 trillion US per year

value of ecosystem services often only recognized when they are lost

• sheet of cells, shape related to location in body
• cover the outside, line the inside of the body
• interact with environment: barriers for threats and exchange of materials

• cells scattered in an extracellular matrix
• found between other tissues
• examples: bone, cartilage, fat, blood

• cells made of filaments containing actin and myosin

3 types:

skeletal - attached to bone and tendon

smooth - involuntary body activities

cardiac - heart walls

• reciept, processing and transmission of information
• neurons transmit impulses
• gila support neurons

• requires communication annd feedback between cells, tissues, organs and environment
• endocrine system - hormones

gradual changes affect whole body

• nervous system - nerve impulses

immediate changes, may be localized

• physiological adjustment in response to change in environment
• type of phenotypic plasticity
• not heritable

• changes in phenotype increasing survival and reproduction
• heritable

• maintains internal environment when external environment changes

internal environment changes as external environment changes

• maintaining internal environment at relatively constant conditions
• temperature, pH, blood glucose, salinity
• regulated by feedback

• enzyme function
• metabolic efficiency
• structural integrity of cells, proteins

• daily cycle of physiological patterns

temperature, blood pressure, sleep/wake cycles

• can be maintained with minimal cues

blind mole rate exhibit daily cycles

• disruption cause problems

• all chemical reactions within an organism

energy to fuel cellular processes, to build proteins, lipids, nucleic acids

• metabolic rate -> energy used over a period of time

heat loss, oxygen used, calories consumed

• larger animals have proportionally less surface area to support metabolic needs
• as body size increases, total BMR increases due to increased overall consumption
• mass-specific BMR decreases due to reduced surface area to volume ratio of tissues

use external sources of energy to control body temperature

rely on internal energy (metabolic heat) to control body temperature

body temperature varies with the environment

body temperature is relatively stable regardless of environment

benefits:

• expend less energy to maintain temperature
• enzymes function under a range of internal conditions

costs:

• inactive under poor environment conditions
• costly to maintain multiple enzymes

benefits:

• remain active in spite of poor environmental
• efficient to have optimized enzymes
• efficient to have optimized enzymes

costs:

• expend A LOT energy to maintain temperature

loss of heat by evaporation of water

emission of electromagnetic radiation

direct transfer by contact

moving air removes radiated heat or water

• the conversion of liquid sweat to vapor results in heat loss, cooling the body
• vasodilation increases heat transfer from the body to the environment
• fat, fur, feathers keep birds and mammals warm
• mammals raise fur and birds raise feathers when cold to trap warm air

the number of molecules of solute per liter solution

have the same osmolarity as its environment

controls osmolarity independently from its environment

water is organism is equal to water in environment

water, salts continuously diffuse

• water in organism is less than water in environment
• water moves in and salt move out
• gain water by osmosis, excrete large amounts of highly dilute urine

• water in organism is greater than water in environment
• water moves out and salt move in
• can become strongly dehydrated, compensate by drinking large amounts of seawater

• animals obtain water through eating and drinking
• animals lose water through secretions and excretion
• water loss is a major challenge

• type of metabolic waste to be excreted
• waste product from breaking down protein, nucleic acids
• must balance toxicity of waste with cost of waste production (energy/water loss)

• relatively non-toxic
• does not dissolve in water, reduces excretory water loss
• VERY energetically costly
• reptiles/birds, insects

• low toxicity
• moderate water loss
• energetically costly
• many land animals

• toxic
• no internal water loss, but must be diluted in water
• aquatic animals

1. filtration

• excretory tubule collects water, small solutes from blood (called filtrate)

2. reabsorption

• water, essential solutes recovered from filtrate

3. secretion

• solutes (toxins, excess ions) added by selective secretion

4. Excretion

• filtrate released as urine

1. Proximal Tube

• resorption of water, salt, ions, nutrients
• waste start concentrating
• toxins actively secreted into filtrate

2. descending loop of henle

• more water reorption
• epithelium only permeable to water (aquaporins)

3. Ascending loop of henle

• no water transport
• salt moves out to maintain osmolarity of interstitial fluid
• waste low in volume, but more dilute

4. Distal tubule

• regulates salt (K+)

5. Collecting duct

• formation of urine

• mammals produce hyperosmotic urine to reduce water loss
• steep osmotic gradient created in part by countercurrent system
• gradient also requires active transport of NaCl
• reducing water loss is energetically costly

ingestion -> digestion -> absorption -> elimination

straining small food from surroundings

live in or on food

suck fluid with nutrients from living host

eat relatively large pieces of food

digestion and distribution of nutrients in same place

single location for ingestion and excretion

complete digestive tract

organized into compartments for digestion, storage, absorption

• ingestion, initial digestion of carbohydrates
• chewing -> mechanical digestion
• saliva -> chemical digestion
• food moves down the pharnyx and esophagus

• storage and digestion of proteins
• gastric juices -> chemical digestion
• stomach churns to aid digestion (creates chyme)

• gastric juices are inactive until released into lumen
• mucus from gastric glands protects stomach lining
• new layer of epithelial cells every 3 days
• gastric juices restricted to stomach by sphincters

• digestion and absorption of nutrients
• small in diameter
• duodenum -> digestion complete
• Jejunum and ileum -> absorption and digestion of fat

• colon -> completes water resorption
• cecum -> fermentation
• rectum -> storage of feces
• anus -> anus

• different combination of teeth for different food sources
• different sizes and lengths of alimentary canal components to process different food

carnivore:

• expandable stomachs for large meals
• relatively short alimentary canal

Herbivores

• relatively long alimentary canal
• bacterial or protist symbionts to break down cellulose
• symbionts often housed in specialized structures

• in birds, mammals, and most insects sex is determined by chromosomes
• in many fish and reptiles, sex is determined by temperature during development
• some are hermaphrodites

• fusion of haploid gametes to form a diploid zygote
• gametes formed by meiosis
• reproduction is primarily or exclusively sexual for most animals

• fragments can become new individuals
• parthenogenesis/haplodiploidy

pros:

• great for sessile organism
• great in stable environments
• may be less costly

Cons:

• reduces genetic variation
• accumulation of deleterious mutations

• in a population of females that reproduce asexually, every individual can produce young
• in a sexual population only females have young
• the asexual population can produce offspring at twice the rate of the sexual population
• selection should favor population with more efficient reproduction

• parasites selectively infect the most common host genotype, causing common genotypes to crash
• sexually reproducing hosts experience new gene combinations-can evolve resistance
• asexual hosts must rely on random mutation
• disease vulnerability is a big potential fitness cost

• stressful conditions
• day length
• food availability
• density

• female releases eggs into the environment male fertilizes them with sperm
• this usually requires a moist habitat

• sperm deposited in or near female reproductive tract
• often preceded by courtship behavior
• requires compatible reproductive systems
• embryo develops in egg or is internally gestated
• increased parental care

• directed and efficient distribution of O2 and nutrients and collection of CO2 and waste
• found in most animals

• heart pumps hemolymph through circulatory vessels to hemocoel
• hemolymph exchanges resources directly with tissues
• heart relaxes, hemolymph pulled through pores that close when heart contracts

pros:

• less energetically costly
• direct delivery of nutrients and waste between hemolymph and tissues

cons:

• lower pressure and flow rate
• resource delivery not directed at specific tissues

• blood confined to vessels
• heart pumps blood through vessels that branch and infiltrate tissues and organs
• exchange between blood, interstitial fluid and body cells
• efficiency delivery of CO2 and nutrients to specific tissues

• blood through heart once
• 1 atrium, 1 ventricle
• moves from heart -> gills -> body -> heart
• lower blood pressure through body

• blood through heart twice
• pulmonary and systemic circuit
• higher blood pressure

start at R side of heart -> O2 poor blood to lungs/skin -> O2 rich blood back to L side of heart

start at L side of heart -> O2/nutriennt rich blood to body -> CO2 rich blood back to R side of heart

• 2 atria, 1 ventricle with a central ridge
• gas exchange using both lungs and skin
• can adjust circulation when lungs are not in use

• 2 atria, 1 ventricle with incomplete septum
• can bypass pulmonary circuit when necessary

• 2 atria, 2ventricles
• as endotherms, require high rate of O2 delivery
• also create more CO2 and waste

• rhythm from regular contraction (systole) and relaxation (diastole) - 0.8 sec cycle in humans
• valves keep blood flowing in the right direction
• beat originates in the heart

endothelium surrounded by thick walls

• smooth muscle (flexible) that dilates or constricts to control blood flow
• connective tissue (strong) supports the high pressure of blood flow from the heart

walls about 1/3 thickness of arteries

• same tissue composition as arteries
• blood flowing back to heart as much lower pressure
• valves maintain unidirectional blood flow

• slightly wider than a red blood cell
• thin walls: just endothelium and basal lamina (exchange between blood and interstitial fluid)
• flow varies depending on organ/structure
• flow regulated by arterioles sphincters

• blood flow velocity drops when blood enters arterioles, capillaries
• large vessels branch into many smaller vessels
• increase in total cross-sectional area decrease velocity
• blood flows from areas of high pressure to areas of low pressure

• ventricular contraction generates pressure
• systolic pressure: highest pressure, ventricles contract
• diastolic pressure: lower pressure, arteries bounce back
• mean pressure decreases as blood moves away from the heart (narrowing of blood vessel increases resistance

• 55%
• liquid matrix where nutrients, wastes, gases, and hormones travel
• dissolved ions: buffer blood and maintain osmotic balance and affect muscle and nerve activity
• plasmas proteins: buffer blood, defense (antibodies), clotting factors

• 44%
• erythrocytes
• most numerous blood cells
• biconcave shape increases surface area
• hemoglobin: iron-containing protein transports O2
• lack nuclei and mitochondria (More hemoglobin)
• each cell transports 1 billion molecules of O2

• <1%
• leukocytes
• 5 major types
• fights infections
• increase in numbers when you are ill

• <1%
• fragments of specialized bone marrow cells
• clotting

• from multipotent stem cells located in bone marrow
• blood cells replaced regularly
• O2 delivery low, kidneys secrete a hormone that stimulates red blood cell production

• uptake of molecular O2 from the environment and the discharge CO2 to the environment
• gases move from areas of high partial pressure to areas of low partial pressure
• gases diffuse across a moist respiratory surface
• rate of diffusion related to surface area and distance

tracheae: air tubes branch throughout body

• connected to environment by pores
• branches found close to every cell

O2/CO2 transfer complete by tracheae

• separate from circulatory system
• hemolymph distributes nutrients, collects waste

• water contains less O2 than air
• gills have surface area for gas exchange
• gas exchange maximized by counter current flow
• gradient increases diffusion rate of gases between blood and gills

• lungs provide localized gas exchange in one part of the body
• linked with the circulatory system
• partial or sole means of gas exchange for most tetrapods

• air travels from larynx to trachea to bronchi, entering lungs
• air filtered in bronchioles which are covered by cilia, mucus
• gas exchange in alveoli at tip of bronchioles

• lower lung surface area than amniotes
• use positive pressure breathing

lowers floor of throat, contrasts throat muscles

push sir from oral cavity into their lung

• air sacs act as bellows to keep air flowing
• 2 cycles of inhalation/exhalation for air to complete circuit
• air flow is unidirectional (fresh air and O2 reduced air do not mix)

negative pressure breathing

inhalation

• muscular contractions expand thoracic cavity
• lower cavity in lungs
• air rushes in - inhalation

exhalation

• muscles relax
• volume of thoracic cavity reduced
• air forced out - exhalation

• hemoglobin has 4 subunits; each has a heme group with an iron atom (each iron atom binds 1 O2 molecule)
• binding of O2 increases affinity of hemoglobin for more O2
• CO2 production promotes O2 unloading (change in blood pH decreases affinity for O2)

• CO2 is a waste product of cellular respiration
• most is converted to bicarbonate in erythrocytes, then travels in plasma to lungs
• converted back to CO2 in lungs, then diffuses out of blood and into alveoli to be removed

• breathing controlled by medulla oblongata
• pH of cerebrospinal fluid indicates CO2 level (H+ from bicarbonate reaction lowers pH)
• as metabolic activity increases, decrease in pH leads to signal to increase breathing

receive signals from other neurons

contains most organelles

where signal is generated

transmits signals to other neurons

send signals

chemical messenger

branches that form the synapse

receive signals

1. sensory input: sensory neurons transmit information about stimuli

2. integration: brain integrates information and considers immediate context and experience; mostly interneurons

3. motor output: trigger output such as muscle or gland activity; motor neurons

difference in charge across a membrane when cells are not communicating

shift in membrane potential that varies in magnitude and direction

rapid, massive change in membrane potential resulting in communication between cells

• uses ATP to move Na+ out and K+ in
• for every 2 K+ in, 3 Na+ move out
• ensures that K+ concentration higher inside neuron
• establishes electrical gradient

• K+ leak channels lead to K+ diffusion out of cell
• buildup of negative charge due to loss of K+
• too much negative charge opposes flow of K+
• Na+ leak channels exist, but in smaller numbers

• alone, K+ moves out along chemical gradient, electrical gradient favors diffusion
• alone, Na+ moves in along a chemical gradient, electrical gradients favors diffusion out

1. depolarization

change in membrane potential from highly negative to zero to positive

2. repolarization

return to negative membrane potential

3. hyperpolarization

undershoot before return to resting potential

• stimulus depolarizes membrane, voltage-gated Na+ channels open (Na+ ions ENTER cell)
• more voltage gated Na+ channels open (depolarization reaches threshold, Na+ moves toward Ena)
• voltage-gated Na+ channels inactivate (eventually close)
• voltage gated K+ channels open (K+ ions LEAVE cell, K+ move towards K+ equilibrium potential)
• voltage-gated K+ channel close (caused undershoot and eventual return to resting potential)

• communication between neurons and other cells
• can be electrical or chemical

• action potential depolarizes terminal membrane
• prompts vessels release neurotransmitter
• neurotransmitter binds to ligand-gated channel
• ions diffuse across membrane
• create graded potential

excitatory postsynaptic potential

inhibitory postsynaptic potential

adding together postsynaptic potential

• leads to action potential or prevents action potential

they appeared billions of years, but more organized nervous systems date back to the cambrian explosion

• nerve net controls gastrovascular cavity
• specific routes for information in sea star, but limited central processing

• cephalization: clustering of sensory neurons and interneurons in front of body
• simple CNS: brain and nerve cords
• more complex CNS: includes ganglia (clusters of neurons), regional specialization

• neurons for integration
• brain and spinal cord

• neurons carrying information into CNS
• nerves and ganglia

cells that support neurons

• nourish neurons and regulate extracellular fluid
• insulating axons

different cells have different functions

• produce myelin sheath
• restrict transport of substances form blood to CNS
• protect against pathogens

brain and spinal cord

• develop from dorsal hollow nerve chord

grey matter: neuron body cells

white matter: bundled axons

cerebrospinal fluid

• supplies CNS with nutrients, hormones, removes wastes

• transmits information to and from CNS
• regulates movement, internal environment
• afferent neurons: PNS gives info to CNS
• efferent neurons: PNS gives info to muscles glands, endocrine cells, broken into motor system and autonomic nervous system

• neurons carry info to skeletal muscles
• voluntary or involuntary (Reflex)

• 3 divisions: sympathetic, parasympathetic, enteric
• generally involuntary
• control digestive, cardiovascular, excretory and endocrine organs

fight or flight

rest and digest

forebrain, midbrain, hindbrain

complex processing, smell, sleep, learning

routing of sensory info

involuntary activities, motor activities

• forebrain
• center for learning, emotion, memory, perception
• voluntary motor function

• hindbrain
• movement, motor skills, visual and auditory input

• forebrain
• thalamus: sensory input to cerebrum
• hypothalamus: internal regulation

• midbrain and hindbrain
• integrates hearing, visual reflexes
• medulla and pons: automatic functions, coordinated movement

• decision-making
• speech
• skeletal muscles
• motor cortex - control on skeletal muscles

• touch
• sensory info
• somatosensory cortex - sense of touch

vision

hearing and language

• motor cortex and somatosensory cortex neurons arranged by the body part producing or receiving signals
• areas correlate with numbers of sensory neurons, not size of body part

• the limbic system, made up of many different parts of the brain, is associated with emotions
• generation and experience of emotion from interactions between limbic system and other parts of the brain
• emotional memories stored in amygdala

lasting change in behavior due to experience

retention of learned information

• holds info briefly, lost if not important
• temporary links in hippocampus

• more secure info retention
• connections in cerebral cortex

• associated with learning
• useful synapses stay active, useless ones lost
• synapses added o removed
• existing synapses strengthened or weakened

different ways to learn different things

• motor skills learned by repetition, become unconscious tasks
• more complex skills lead to the production of new synapses
• memorization may rely on changes in strength of existing synapses