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Definition
| traits which aid an organism in obtaining food and likelyhood of reproducing |
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Definition
| analyzed fossil layers and proposed the idea the earth was older than listed in the bible |
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Definition
| came up with the theory of inheritance of acquired characteristics |
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| studied in Asian jungles. Concluded similarly to Darwin |
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Term
| Descent with Modification |
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Definition
| diverse forms gradually acquire traits which make them different from their ancestors. |
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Definition
| the process by which individuals with certain heritable characteristics tend to survive and reproduce more successfully ( mechanism of evolution) |
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| Darwin's Observations of Evolution |
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Definition
1. Organisms have great potential firtility which permits exponential population growth
2. NAtural populations remain fairly constant in size
3. Natural resource are limited and there is a struggle for existence in populations
4. Variations occur in populations
5. Variation is heritable- varying organisms show different survival and reproduction favoring better traits |
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Term
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Definition
| natural selection removes individals of the 2 extremes of a phenotype which decreases variation and makes the phenotype frequnecy more narrow |
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Definition
| natural selection pushes frequency of a phenotype towrd a specific extreme |
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Definition
| natural selection removes the median phenotype |
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| What are the 4 mechanisms of evolution |
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Definition
| NAtural selection, mutation, Genetic Drift, Gene Flow |
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Definition
| individuals with better heritable characteristics surviv and pass on their traits. ( only mechanism which consistently causes adaptive evolution) |
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Definition
| change of nucleotide sequence of an organisms DNA. ( doesn't happen enough to be a key mechanism, increases variation) |
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Definition
| Change in the gene pool of a population due to chance. Most dramatic in small populations |
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Definition
| a sharp reduction in population size due to environmental effects |
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Definition
| loss of genetic variation when a new population is established by a small group of individuals seperated from a larger population |
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Definition
| the transfer of alleles from one population to another as a result of the movement of individuals or gametes. |
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Definition
| changes in a population gene pool over a succession of a few generations without changing species |
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Definition
| evolutionary change on a grand scale including speciation and mass extinction |
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Definition
| a new species evolves from 1 species |
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Definition
| new species ( 2+) evolves from 1 species |
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Term
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Definition
| 1st part of the name is the genus. The 2nd part the specific epithet. The combination of both is the species name |
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Term
| Biological species concept |
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Definition
| a species is a groups of populations whose mebers have potential to interbreed in nature and produce fertile offspring. |
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| typological species concept |
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Definition
| individuals that look alike are the same species |
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Term
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Definition
| 2 different species have similar species but do not share a similar ancestor |
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Term
| analogous structures/ homolohgous structures |
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Definition
| structures that appear similar but do not due to similar ancestors. structures that do appear similar b/c of shared ancestry |
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Term
| Ecological species concept |
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Definition
| species defines by their ecological niche( what they do in the environment and the conditions they need to survive in) |
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Term
| phylogenetic species concept |
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Definition
| a species is the smallest group of individuals that share a common ancestor ( compares species based on their genetic makeup) |
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Term
| types of prezygotic barriers |
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Definition
temporal isolation( mating season is different btwn 2 species.
habitat isolation ( 2 species live in same area but different habitats)
behavioral isolation ( 2 species have different mating rituals)
Mechanical isolation ( species are not physically designed to mate)
Gametic Isolation ( male and female gametes differ and fail to unite) |
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Term
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Definition
reduced hybrid viability ( hybrids fail to develop).
reduced hybrid fertility.
hybrid breakdown ( not successful uniting of gene pools. organism not strong enough to survive or is infertile |
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Term
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Definition
| a population is geographically divided and new species are formed ( needs selection pressure to cause evolution) |
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Term
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Definition
| new species may arise without geographic isolation |
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Term
| food resource partitioning |
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Definition
| species divide up food resources of an ecosystem |
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Definition
| organisms have different reproductive success due to their ability to find mates |
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Term
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Definition
| regions in which members of different species interact and mate |
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Term
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Definition
1. reinforcement- hybrids are unfit and reinforce the continuation of 2 species
2. Fusion- 2 species come together and produce a new species with traits from both
3.stability hybrids exist yet each species maintains its individuality |
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Term
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Definition
| species change quickly as they arise and then plateau |
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Term
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Definition
| species change slowly over time by accumulating new traits |
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