A group of population of different specied livingn in close porximity that interact
three community interactions.
Contrast interspecific and intraspecific competition
Interspecific grasshoppers and bison compete for grasse
Intraspecific is between itself
Is competition a +/+, +/-, or a -/- situation
Explain and give an example of competitive exclusion.
A forest for space and sun. competitive exclusions makes a specicies places they could live smaller
When two organisms are competing for exactly the same
resources (ie-food), either the more efficient one will drive the less efficient one out
of the area (or into extinction), or the less efficient one will modify what it eats, or
where it lives.
is what it is best at doing, including
the sum of all biotic and abiotic factors a species uses.
organism’s fundamental niche is modified to accommodate more efficient
organisms, the new niche is called its
Explain and give an example of character displacement. Which types of species are most likely to experience character displacement? Why?
Character displacement is when an organism changes its
natural behavior in order to avoid direct competition with a more efficient organism.
(Example, two species of middle eastern mice, A. cahirinus and A. rassatus live in the
same environment, but A. cahirinus forages for food at night, while A. rassatus
forages for food during the day
sympatric species are more likely to experience this.
(+/-) Predation occurs when one organism eats another one. The organism that
gets eaten is called the Prey, and the organism that eats it is called the Predator. Sometimes
predators eat each other (lions killing tigers, Brown bears killing Black bears), but this is rare. Different predators will usually use character displacement to partition resources, rather than
compete directly for the same food, or (even worse) fight and kill each other
Where a harmless animal will adopt the same colours as a
similar looking poisonous animal to encourage predators not to eat it. (Example: the
harmless Hawkmoth larva will adopt the colourations and behaviors of a poisonous
snake. Figure 54.5c).
Where two or more poisonous species will adopt similar
colours and markings so that predators will eventually learn not to eat either one of
them. The one that is less poisonous is classified as being the one that mimics the
more poisonous one. (Example, the Monarch and Viceroy Butterflies. Figure 54.5d,
the Cuckoo bee and Yellow jacket wasp.)
Also known as ‘camouflage,’ where prey
animals are disguised to blend in with their environment, making it harder for
predators to see them.
Many prey animals accumulate toxins in
their systems that will make any predatory animals that eat them sick. Such animals
will often display bright colours as a warning to predators not to eat them.
(+/-) Where the symbiont benefits but the host is harmed (ie-intestinal
parasites in the human intestine).
: (+/0) Where the symbiont benefits but the host neither loses nor gains
anything from the interaction (ie-Epiphyte plants living atop taller plants, allowing the
epiphytes to get sunlight).
(+/+) Where both host and symbiont benefit from the interaction
Explain species diversity, a fundamental feature of a community.
1.Species richment how many of a species are found
2. Specieces abundance the portion a species has relative to al other species in the community
Explain and give an example of the trophic structure of a community.
Plants and Phytoplankton (including algae) are the photosynthetic organisms that are classified
as Primary Producers. The non-photosynthetic organisms that eat the primary producers are
called the Primary Consumers. Insects and Zooplankton (ie-Krill) are considered Primary
Consumers. Small, relatively unsophisticated animals that eat the primary consumers are called
Secondary Consumers. Many insectivores (that eat insects) are Secondary Consumers (ie-fish
and birds that eat insects). Larger, more sophisticated animals that eat the secondary
consumers (ie-snakes that eat rodents, Seals that eat fish etc.) are called Tertiary Consumers,
and very large, intelligent animals with highly developed hunting characteristics (claws, wings,
acute eyesight etc.) are called Quaternary Consumers. Killer Whales, Hawks, Lions, Tigers,
Bears, and other sophisticated hunters are considered to be Quaternary Consumers. Obviously,
the lines between these types of consumers can become blurry, as is the case with omnivores. Decomposers(BASEE)
The reason why there are only
four types of consumers (primary to quaternary), and food chains are relatively short is
believed to be related to the relative inefficiency of the bioconversion process.
dynamic stability hypothesis
States that food chains are short because if they were longer, the loss of one link in the chain
would lead to the loss or extinction of many types of consumers above it.
What three kinds of species are important to a community?
Explain why some species are dominant species and the possible effects on the community if these species are removed.
The Dominant Species of an ecosystem is the most abundant species
present. Have few predators they effect the community as a threat or as a helper
Explain and give an example of a keystone species. What is the effect on the community if a keystone species is removed?
A keynote species is a species that may only be present in small numbers,
but which has a dramatic effect on the composition of the ecosystem. An example of a keynote
species would be the Sea Otter, which is highly important to the composition of the sea
ecosystem off the coast of British Columbia (Figure 54.18). The Sea Otter is a secondary
consumer of Sea Urchins, which are the primary consumers of Kelp (a seaweed).
Explain and give an example of a foundation species. What is the effect on the community if a foundation species is removed?
Ecosystem Engineers are species that physically change the
landscape. Examples of Ecosystem Engineers include Beavers that cut down trees to make
Beaver Lodges, and Termites that consume wood to make termite mounds. depends on the needs the inpact of removal
Define anthropogenic disturbance and give an example.
Human impact such as clear cutting a forrest or introduction of invasive species
When a severe disturbance like a flood or forest fire completely
destroys an ecosystem, and removes all life, life will eventually return, and a new ecosystem
will be rebuilt. Possibly the same ecosystem that existed before, with the same composition of
animals, plants, insects etc. However, this will not happen right away, mainly because forest
fires and floods change the landscape so dramatically, often altering the pH and oxygen content
of the soil, that the original plants and other p
Define Disturbance and give examples.
events such as floods and forest fires can
disturb the ecosystem by killing or chasing away some members of the community, or removing
some types of plants etc.
Explain the intermediate disturbance hypothesis.
The Intermediate Disturbance Hypothesis states that if both
frequent disturbances, and rare disturbances to an ecosystem will lead to a lack of biodiversity
(how many different organisms are present). This is because severe or frequent disturbances to
the ecosystem will kill of the more fragile organism, allowing only the stronger ones to
dominate the landscape. At the other extreme, if the ecosystem remains undisturbed for too
long, the more efficient organisms will drive the less efficient ones into extinction (the
Competitive Exclusion Hypothesis). By contrast, an intermediate number of mild disturbances
will actually be helpful, in that the disturbances will occasionally kill some of the more
dominant species off, and give new organisms a chance to get a ‘foot hold’ in the community
that they wouldn’t have had otherwise.
Explain the general morphology (structure and function) of fungi.
Fungal cell walls are composed of chitin . Hyphae are filamentous structures that make up a fungal body. A mycelium is a visible mass of hyphae and increases suface to volume ratio. Spores are the reproductive structures of fungi, and in many species a fruiting body produces the spores.
type a hyphae
Type a has nucli septums cell walls and pores aka septate
aka coenocytic has only nuclei and cell walls
Explain the 4 ways fungi obtain nutrition.
Decomposers : break down non living organisms
Parasites : absorb from living hosts . some are pathenogenic
Mutualists: live in host but reciprocate it
Mycorrhizal fungi specialized hyphae that enters the cell wall and extracts nutrients from the host
Ecto forms a sheath over the surface of a root and typically grow into extracellular spaces of the root cortex.
arbuscular mycorrhizal fungi.
extend branching hyphae trough the root cell wall and into tubes by pushing inward into the root cell wall.
Explain the benefits of mycorrhizal fungi to both the fungi and plants.
Plants depend on fungi for essential nutrients they promote growth as well.
Diagram and explain the general life cycle of fungi. Include terms/labels: haploid, diploid, heterokaryotic, plasmogamy, karyogamy, zygote, mycelium, meiosis, germination (mitosis), spores, spore-producing structures, asexual reproduction and sexual reproduction.
Most fungi reproduce both sexually and asexually. What determines which method the fungi will choose? Which sub-group of fungi use only asexual reproduction?
If pheromones are present they will reproduce sexually. deuteromycetes
cladogram of fungi
Explain how Zygomycetes (Pilobolus) distribute their asexual spores.
asexual sporangium aims spore deliver y towards the light bcause that’s where grass grows
launches the sporangia on a stream of water apprx 2 meters in distance – grazing animals spread the spores in their poo
Compare the sexual reproduction of Zygomycetes, Ascomycetes, and Basdiomycetes.
Zygo- resistant zygosporangium as a sexual stage coenoccytic hyphae exept in structures that produce reproductive structure
Asc – sexual spores are borne in sacs called asci and have a vast number of asexual spores.
Basid – elaborate fruiting bodies containing many basidia that produce sexual spores
Explain fairy rings
A “fairy ring” forms as hyphae grow outward from a food source, producing mushrooms near the outer edge of the ring.
Which phylum of fungi is best at decomposing the complex polymer lignin in wood?
Organismal ecology concerned with how organisms structure physiology behavior interacts with its environment
Link evolutionary time to ecological time
Differential structurres and reproduction over ecological time(MINUTE TO MINUTE INTERACTIONS)
In general, what limits species distribution?
Geographic location behavior abiotic and biotic factors
How do species overcome geographical barriers? Give examples of intentional and unintentional distribution.
1.Cocklebur latches in and animal distributes and shit
2. Unatural distribution could be unitentional (brown tree snake) introduced to Guam as a stow away no predators and plenty of num nums
intentionalllllll – kudzu good cattke food and helps with soil erosion buttttt it doesn’t have any predators so holy shit did it spread mutha fucker
Describe the many factors that can limit species distribution. Include examples.
Behavior can limit distribution by not taking advantage of the potential range Ex corn borer larvae (can feed on other things lil idjets)
Living factors like other organisms Urchin and limpets are predators of seaweed Paristisim – ca tree frogz problem is its getting warmier up in dis bitch. Frogs are relocating to hight altitudes where it be cool and fresh den they come in contact with a deadly fungus and dat aint cool amirite.
Physical Factors – temperature + light +
wind + percipitation (climate)
soil structure, fire
Species distribution is limited on a large scale (biome). How does this affect distribution of species in areas where different biomes meet?
Species distribution is not always limited on a large scale. How might species distribution be limited in a forest ravine?
Layering and different temperature changes
indvivuals are the same specieses living in the same place at the same time.
Explain what members of the same population share.
relying on the same resources they are influenced by similar envronmental factors they interact with each other and breed
# of individuals per unit area or volume number of oaks per sq meter in a forrest
pattern of spacing between individuals within boundaries of a population
: Studies of vital statistics of population and how change over time
Ecologists look at fertility or reproductive tables – bitches only and only follow lil bitches aka female offspring
Explain the methods that ecologist use to measure density.
Counting individuals or mark and recapture
Explain and give examples of the three patterns of distribution.
Clumping – larger number of individuals in high resource areas of the habitat –could increase sexual reproduction rates – could also increase predation rates
Uniform – in territorial species – spotted napweed allelopathy –
Random – non social nothing drawn together – bear
Explain what a life table is and how it can be used in population ecology.
age specific summaries of the survival patterns of a population and can be used to study populations in general
Explain the three types of survivorship curves and give an example for each.
Type 1 : death rates are low until middle age after that increase in death rates as individuals age(humans/large mammals/few offspring/care for the lil idiots decreasing death rates
Type 3:high death rate of the young if surviing babyhood you probsly will live along time (fish,plants,invertibrates, oaks, maples lotsa off sprang ,baybays are on der own)
Type 2: constant deff r8 regardless of age
Explain what fertility schedules are and who in the population is recorded in them.
An age specific summary of the amount of females in each age group. Measures the reproductive output of output of each from life to death.
Contrast semelparity and iteroparity
Senolparity have one reproductive even t=with a large number of offspring example the agave tree
Iteroparity – repreated reproductive events – few offspring produced.
Define exponential growth and explain the formula ecologist use to calculate exponential growth.
Formula: dN/dt = rmaxN
Population regardless of life history survivorship curve) potential tro increase number wheb resources are plentiful exponential growth
Ecologist exponential growth per capita(per individual)
dN = number of deaths in the population in a given period of time
dt = time
rmaxN = per capita increase of increase
Explain why exponential growth is graphed as a “J” shaped curve. What effect will different numbers in the starting population have on the shape of the curve?
J shaped shows a catastrophic event such as a a species being introduced to a new environment smaller numbers usually mean greater growth to come.
Contrast the exponential model with the logistic model. In the logistic model, what is K? (Be sure to include the major assumption of the logistic model)
Ideal lab conditions paramecium = logistic growth
Assumes environmen imediatlly respinrs ro the addition o f new individuals
Population number over shots carrying capcity
K is the carrying capacity Number of individuals a habitat can support is limited in
Unstable environment, density independent
small size of organism
energy used to make each individual is low
many offspring are produced (semelparity)
short life expectancy
each individual reproduces only once
type III survivorship pattern
in which most of the individuals die within a short time
but a few live much longer
Exponential Growth J-shaped curve
Stable environment, density dependent interactions
large size of organism
energy used to make each individual is high
few offspring are produced (iteroparity)
late maturity, often after a prolonged period of parental care
long life expectancy
individuals can reproduce more than once in their lifetime
type I or II survivorship pattern
in which most individuals live to near the maximum life span
Logistic models S-shaped Curve
Explain the density-dependent extrinsic factors discussed in class.
Extrinsic factors belong to the environment
Dompetition for resources many predators feed on many prey types
Increase desity of population of 1 preytype and a predator exclusivily,disease in creases with higher density
Explain how the white-footed mouse is an example of intrinsic density-dependence.
Factors belong to the organism or da fizzie ol OG
Reproduction rates in the whitfooted mouse decrease as population increases
Aggressive bahviour alzo increzes dis can cause a stress syndrome effecting hormone levels that delay sexual maturity and shrinks reproductive structures and weakens the immune system. Birthrates decrease death increases this occurs even with space and shit
Explain predator/prey and environmental effects on population dynamics.
More prey more predetors but then predators my switch and give a chance for rebuilding.
Explain what value can be gained by developing age structure graphs for human populations.
Shows where an explosion of growth may be as well as the reproductive rates and tendancies
Do Humans have a carrying capacity?
Yes. There is only so much space for us.