Is supported by and makes sense of any osbservation
Homologous to ancestors, or common ancestors
Unique to a geographic area
Is a graded change in a trait along geographic areas
consists of the movement of alleles among populations
Alleles can be transferred through the movement of fertile individuals or gametes (for example, pollen)
describes how allele frequencies fluctuate unpredictably from one generation to the next
tends to reduce genetic variation through losses of alleles
Sudden reduction in a population do to the environment changing
Bottle neck effect
Few individuals from a larger population become isolated from that larger group and start there own population
Form of natural selection in which individuals with a certain inherit gene mate with another of the same have have successful mating
Makes the difference between the sexes, in the secondary sexual characterstics
Better chance at survival, and is most closely related to stabilizing selection
The regular occurrence of geological or meteorological disturbances
Studied Fossil record with catastrophism
What did Darwin Study?
A mechanism for evolution that was supported by evidence
Why have giraffes developed longer necks over time?
Because trees got taller, and evolution to adapt with the environment
What is natural selection based on?
Genetic variation exists within the population, best adopted longer lives is more offspring,(Individuals with favorable traits are more likely to survive and reporduce)
Why is MRSA an example of artificial selection?
Because humans synthesis methacilin and create environment in which bacteria frequently come into contact with methicilin
How would can you explain the fact that human arms, bat wings, and dolphin flippers contain many of the same bones and have developed from very similar embryonic tissues?
Common ancestors and homologos selection
Why is acceptable to say all life on earth comes from a common origin?
All organisms are essentially the same genetic code
Why are old fossils found vs newer fossils?
Deeper in the rock
What are the three mechanisms that cause allele/gene frequency change?
Natural Selection, Genetic drift, and gene flow
What in an Organisms genes is most likely to help the organism respond properly to changes in its environment?
is 52% of loci are heterozygous on average how many are homozygous?
Why can't natural selection fashion perfect organisms?
1.Selection can only act on existing variations
2.Evolution is limited by historical constraints
3. Adaptions are often compromises
4. Chance, Natural selection, and the environment interact
Briefly explain what Hardy-Weinberg equilibrium means and what type of population it describes.
1.There are no Mutations
2.The mating is random
3.No natural selection
4. Large population
5. No gene flow
It Describes a Hypothetical Population that is not evolving
List and Describe the various mechanisms help to preserve genetic variation in a population.
Heterozygous advantage-Maintains two alleles between individuals
Natural Selection- genes that help mating good offspring
List and describe the 3 modes of selection
1. Directional selection- favors individuals at one end of the phenotype range
2. Disruptive selection- favors both individuals at the extreme ends of the phenotype
3. Stabilizing selection- favors intermediate phenotypes and acts against the extremes
Favors Indivudals at one end of the phenotpye range
favors both individuals at the extreme ends of the phentype
favors the intermediate phenotypes and acts against the extreme phenotypes
Evolutions above the species level
Region in which members of different species reproduce hybrid offspring
group of a population, that from 1 split into 2
List and describe the species concepts
States a species is a group of populations whose members have the potential to interbreed in nature and reproduce fertile offspring
Punctuated equilibrium model
describes the periods of apparent stasis punctuated by a sudden change
what are the Prezygotic Barriers?
Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers
Species that breed at different times of the day, different seasons, or different years cannot mix their gametes
Courtship rituals and other behaviors unique to a species are effective barriers
Morphological differences can prevent successful mating
Sperm of one species may not be able to fertilize eggs of another species
What is the possible outcome when closely related species meet in the hybrid zone?
They reinforce the hybrids and diffuse into a single population
Analogous structures that evolve independently
Much evolutionary change in genes and has no effect on fitness and is not influence by selection
What are the taxonomical levels
domain, kingdom. phylum, class, order, family, genus, species
What would the best classification system be based on?
what did the use of computers and software enable scientist to better study in the field of phylogeny?
The research of trees that are parsimonious and likely
In a cladistic approach to systematic, what is the most important for classification?
Shared derived characteristics
Why would species that are not closely related and that do not share many anatomical similarities still be placed together on the same phylogentic tree?
Homologous genes that are highly conserved
What would allow a gene to act as a molecular clock? which would not allow a gene to act as a molecular clock?
When its not acted upon and when it is mutated
Come from a common ancestor
Homoplasy, analogous structures
Similarities and convergent evolution
decent with modification
modified other species by selecting and breeding individuals with desired traits
Consists of all the alleles for all loci in a population
Differential success in reproduction results in certain alleles being passed to the next generation in greater proportions
For example, an allele that confers resistance to DDT increased in frequency after DDT was used widely in agriculture
is the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals
the fitness of a phenotype declines if it becomes too common in the population