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Bio/Int. 2
Lesson 23- Evolution and Genetics
| Term | Definition |
|---|---|
| Gene Pool | the sum of all genetic information carried by the members of a population |
| Mutation | any change in the organism’s DNA, can be good, neutral, or harmful to the organism |
| Population | a group of potentially interbreeding organisms of the same species occupying a certain area |
| Gene Mutation | alteration of a gene resulting in new alleles, this is the source of genetic variation within populations |
| Genetic Drift | this occurs when founders (or colonizers) establish a new population, can also occur after a genetic bottleneck and then interbreeding |
| Genetic Bottleneck | form of genetic drift in which a severe reduction in population size results from a natural disaster, predation, or habitat reduction, causing a severe reduction of the total genetic diversity of the original gene pool |
| Fitness | a measure of an individual’s ability to survive and reproduce |
| Natural Selection | process by which individuals that are better suited to their environment survive and reproduce most successfully |
| Stabilizing Selection | natural selection that prevents overall changes in populations, this works against both extremes within a particular variation |
| Directional Selection | natural selection that favors one extreme end of a particular variation, DDT resistance is an example |
| Disruptive Selection | natural selection that favors individuals at both extremes and results from selection against the middle of the population’s variation, can result in two new and distinct variations |
| Reproductive Isolating Mechanism | a structural, functional, or behavioral characteristic that prevents successful reproduction from occurring |
| Habitat Isolation | occurs when two species occupy different habitats, individuals from these habitats are less likely to meet and to attempt to reproduce |
| Temporal Isolation | occurs when two species live in the same location, but each reproduces at a different time of the year |
| Behavioral Isolation | occurs when there are differences in mating behavior between two species |
| Mechanical Isolation | results from differences in reproductive structures or other body parts between two species preventing mating from occurring |
| Post-Mating Isolation | the result of developmental or physiological differences between the members of two species after mating |
| Gamete Isolation | physical or chemical incompatibility of gametes (egg or sperm) of two different species |
| Zygote Mortality | mechanism that works when offspring of parents of two different species do not live to reproduce |
| Hybrid Sterility | occurs when the hybrid offspring are sterile, example of a cross between a donkey and a horse resulting in sterile mules |
| Gradualism | selection and variation that happens at a slower pace, changes are slow, constant, and consistent |
| Punctuated Equilibrium | selection and variation that comes in spurts and then a period of very little change, then a period of one or few huge changes |
Created by:
ECOTScience10-11
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