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(BIO) ch. 16 and 17 for catherine

change over time
geographic isolation
form of reproductive isolation in which two populations are separated by geographic barriers such as rivers, mountains, or bodies of water, leading to the formation of two separate subspecies
group of similar organisms that can breed and produce fertile offspring
sexual selection
when individuals select mates based on heritable traits
formation of a new species
directional selection
form of natural selection in which individuals at one end of a distribution curve has higher fitness than individuals in the middle or at the other end of the curve
the study of past and present distribution of organisms
analogous structure
body parts that share a common function, but not structure
behavioral isolation
from of reproductive isolation in which two populations develop differences in courtship rituals or other behavior that prevent them from breeding
artificial selection
selective breeding of plants and animals to promote the occurrence of desirable traits in offspring
heritable characteristic that increases an organism's ability to survive and reproduce in an environment
genetic equilibrium
situation in which allele frequencies in a population remain the same
bottleneck effect
change in allele frequencies as a result of the migration of small subgroup of a population
founder effect
a change in allele frequency following a dramatic reduction in the size of a population
Hardy Weinberg Principle
principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change
stabilizing selection
form of natural selection in which individuals near the center of the distribution curve have higher fitness than individuals at either end of the curve
reproductive isolation
separation of a species or population so that they no longer interbreed and evolve into two separate species
homologous structures
structures that are similar in different species of common ancestry
preserved remains or traces of ancient organisms
polygenic trait
trait controlled by two or more genes
natural selection
process by which organisms that are most suited to their environment survive and reproduce most successfully, also called survival of the fittest
gene pool
all the genes, including all the different alleles for each gene, that are present in a population at any one time
temporal isolation
form of reproductive isolation in which two or more species reproduces at different times
single- gene trait
trait controlled by one gene that has two alleles
genetic drift
random change in allele frequency caused by a series of chance occurrences that cause an allele to become more of less common in a population
allele frequency
number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene
how well an organism can survive and reproduce in its environment
vestigial structure
structure that is inherited from ancestors but has lost or all of its original function
disruptive selection
form of natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals in the middle or at the other end of the curve.
molecular clock
method used by researchers that uses mutation rates in DNA to estimate the length of time that two species have been evolving independently
comparison of DNA sequences between species can show how many mutations occurred independently in each group
Charles Darwin
born feb. 12, 1809
went on HMS Beagle's five year voyage in 1831
3 distinctive patterns of biological diversity
1. species vary globally
2. species vary locally
3. species vary over time
Hutton and Lyell
geologists. said that Earth is older than we previously thought. said that processes that changed Earth in the past are the same processes we see in the present
had a false statement that organisms can pass acquired characteristics to their offspring. was first to suggest a link between an organism's environment and its body structure
scientist that stated that if populations grew unchecked, there wouldn't be enough living space and food for everyone
Alfred Russel Wallace
spent year observing and gathering data in Indonesia area and wrote a letter to Darwin. discovered "reproductive isolation" in the Malay Archipelago
descent with modification
living species are descended, with modification, from common ancestors.
according to this all species - living and extinct- are descended from ancient common ancestors
natural selection on single- gene traits
can lead to changes in allele frequencies which changes frequencies of phenotypes
natural selection on polygenic traits
can affect the distribution of phenotypes in 3 ways:
directional, stabilizing, disruptive
evolutionary fitness
the success in passing genes to the next generation
evolutionary adaptation
any genetically controlled trait that increases an individual's ability to pass along its alleles
sources of genetic variations
muatations, genetic recombination in sexual reproduction, lateral gene transfer
lateral gene transfer
passing of genes from one organism to another that is not its offspring
evolution in genetic terms
any change in the relative frequency of alleles in the gene pool of a population over time
what natural selection acts directly on
acts on phenotypes not genotypes
what genetic variation and evolution are studied in
they are studied in populations
The Grants' Investigation
documented that natural selection takes place frequently and sometimes rapidly.
showed that variation within a species increases the likelihood that the species can adapt and survive environmental change
5 conditions to maintain genetic equilibrium
must be random mating
population must be very large
no mutations
no immigration or emigration
no natural selection
Hox genes
determine which part of an embryo develops arms, legs, or wings. Groups of hox genes also control the size and shape of the those structures
small changes in this can cause activity during embryological development to produce large changes in adult animals
evidence of evolution
biogeography, fossils, anatomy and embryology, vestigial structures, genetics (universal code and homologous molecules)