Individuals with one version of a trait have greater reproductive success than do individuals with a different version.
4 different mechinisms of evolution
mutation, genetic drift, migration, natural selection (evolution is a result of natural selection).
Change in allele frequencies in a population. Change due to natural pressures (peper moth).
group of organisms of the same species living in a particular area.
Natural selection (conditions)
variation for a trait, Heritability of that trait, Differential reproductive success based on that trait(more babies). need all 3
measure of relative amount of reproduction of an indivitual witha particular phenotype, compared to the output with alternate phenotypes.
Elements to an organisms fitness
1. measured relative to other genotypes or phenotypes in the poplation.
2. the enviroment
3. reproductive success, compared with organisms in population
(survival of the fittest)
when an organism becomes better matched to enviroment/ features that make them more fit . process of natural selection.
Natureal selection can change the traits of a population in what 3 ways of selection.
Directional, stabilizing, disrupted
ONE extreme from variation of population have higher fitness.
individuals with intermediate phenotypes are most fit
RARE individuals with extreme phenotypes have the hightest fitness
Alteration of base pair sequence of an individual's DNA, alteration occurs in section of DNA that codes for a particular gene. Change in DNA may change the allele. almost always cause early death or lower reproductive success.
mutation inducing chemicals
Random change in allele frequencies that do not influance reproductive success and population expienceses evolution
consequence of genetic drift. occures when alleles frequency in population for a trait reches 100%. all offspring will carry that allele untill mutation occurs.
group of indeviduals that leave the exsisting population. new population will be dominated by the genetic features present in the founding members. the new population expiences evolution.
surviving members of a catastrophic event that have different allele frequencies than the source population and, consequently, the new population will be dominated by the present features in the surviving members.
Migration/ Gene Flow
A group of indeviduals migrates from one population to another. Both experiance change in allele frequencies as indeviduals move in and out.
process by witch natural selection favors traits, such as ornatments or fighting behavior that gives an advantage to indaviduals of one sex in attracting matting partners.
reproductive sucess is determined by humans not nature.
Five Lines of Evidence Demonstraiting the occurance of evolution
-the fossil record
-comparative anatomy and embryology
-laboratory and field experiments
The Fossil Record
physical evidance of organism that lived in the past
patterens in the geographic distribution of living organisms
Comparative anatomy and Embryology
growth, development and body structures of major groups of organisms
The examination of life at the level of individual molecules
Laboratory and Field Experiments
Implementation of the scientific method to observe and study evolutionary mechanisms
makes it possible to determine the age of fossils. absolute and relative age
Body structures in different organisms that, although modified over time to serve different dunctions in different species, are due to inheritance from a common evolutionary ancestor.
a structure on an animal that was once useful but lost its function over time due to evolution.( human appendix)
process of natural selection which features of an organisms not closely related come ot resemble each other as a consequence of silimar selective forces