Evolution Flashcards
Four ways evolution can occur
- Natural selection
- Mutation
- Genetic Drift
- Genetic Shift
Lamarck’s Inheritance of Aquired Charactaristics Theory
Eventually disproven. The concept of use and disuse. Organs that were used would develop, others would atrophy. Changes were called acquired charactaristics.
Origin of the Species three main tenets
- Organisms produce many offspring but few survive to maturity
- Chance variations are inheritable
- Individuals with more favorable traits are more likley to survive and produce offspring (natural selection). Fitness is the reproductive sucess of an individual.
Natural selection is a ___ for evolution
Mechanism
Natural selection is equivalent to
Survival of the fittest
Currently accepted theory is called
neo-Darwinism or modern synthesis
When mutation or recombination results in a change that is favorable to an organisms survival, that change is more likely to pass on to the next generation. This is called _____.
Differential Reproduction
Punctuated Equilibrium
The idea that evolutionary changes occur in massive bursts and not in small incriments.
How did palentology contribute to evolution
Using audioradiography, scientists were able to find a fossil’s age, finding the chronological sucession of species.
Divergence
When the same species in two different locations evolves separately.
Homologous structures
Similar in structure and share a common evolutionary origin, even if they don’t look the same.
Analogous structures
Share a common purpose but evolved separately.
Vestigial Structures
Remnants of organs that have lost their ancestral function.
How did molecular biology contribute to evolution
By looking at DNA sequence, scientists can predict the dgree of similarity between two organs.
Gene frequency
How often an allele apprears in a population
How to calculate gene frequency
Number of people with allele A/Total number of alleles possible
Five requirements of the Hardy Weinberg Equilibrium
- Large population
- No mutations
- Mating is random
- No net migration
- The genes in the population are all equally good at reproducing
p2 + 2pq + q2 = 1
What does each term mean
p2 = frequency of TT
2pq = frequency of Tt
q2 = frequency of tt
You can use these in a type of punnet square to find the percent of each gene type.
Remember that there are ____ as many genes in the population as there are people
Twice
Genetic Drift
Changes in the composition of the gene pool due to chance. Can result when a small population is isolated, natural events.
Gene Flow
Migration of individuals between populations
Directional Stabilization
Pushes the average one way
Disruptive selection
Moves the average into two peaks
Two inherent exceptions to the survival of the fittest
Altruistic behavior, kin selection
Inclusive fitness
The number of alleles that an individual passes on to the next generation, even if only indirectly through altruistic behavior.
Speciation
emergence of a new species.
If you take two species and separate them for long enough, _____ will occur
reproductive isolation
Prezygotic mechanism of reproductive isolation
prevent formation of zygote completely
Postzygotic mechanism of reproductive isolation
allow for gamete fusion but produce infertile offspring
Temporal Isolation
Two species may breed during different seasons or times of day preventing interbreeding
Ecological Isolation
Two species living in the same territory but in different habitats. They rarely meet and thus rarely mate.
Behavioral Isolation
Members of two species are not sexually attracted to eachother because of differences in pheremones or courtship displays.
Reproductive isolation
The genetalia are incompadible
Gametic Isolation
Intercourse can occur but ferilization cannot.
Hybrid Inviability
Genetic incompatibilies between two species abort hybrid zygote development, even if species does not occur.
Hybrid Sterility
Offspring are sterile
Hybrid breakdown
First generation hybrids are viable and fertile, but second generation are not.
Adaptive radiation
When a single ancestral species gives rise to a number of different species
Convergent evolution
Independant development of similar charactaristics
Divergent Evolution
Independant development of dissimilar charactaristics. They did begin together at some point.
Parallel Evolution
Refers to the process whereby related species evolve in similar ways for a long period of time in responce to analagous environmental selection pressures.
Primordial Soup
The very early planet consisted of high amounts of carbon, hydrogen, and nitrogen, less oxygen. With massive amounts of energy bonds formed.
Protobionists
The collection of organic polymers that are believed to have been the primitive ancestors of living cells. Abiotically produced polymers were found to assemble into small living things.
What was the first genetic material
RNA. Evolution probably favored RNA sequences whose three dimentional conformations were more stable and could replicate faster. Evolutionary trends then led to the eventual establishment of DNA.
Microspheres are charactarized by (3 things)
- They are composed of tiny, abiotically produced proteinaceous droplets
- They have a selectively permeable membrane
- They have an internal chemical environment disticnct from that of their surroundings.
