exam one Flashcards
Evolution
Heritable change in one or more characteristics of a population or species from one generation to the next.
What is the process of natural selection?
More offspring are produced than can survive
Competition for limited resources
Individuals with better traits flourish and reproduce
Provide evidence the species have changed over time
Fossil records
Biogeography (important)
Convergent evolution
Selective breeding
Homologies (anatomical, developmental, and molecular)
Explain homologous structures and give examples
Homologous structures are structures that resemble each other and are derived evolutionarily and developmentally from the same source structure. Examples include arm bone similarities between humans, bats, and whales.
Explain analogous structures and give examples.
Analogous structures are structures that seem similar but do not originate from a common ancestor (source structure). Examples can be the long noses of echidnas and anteaters.
Microevolution
changes in a single gene in a population over time
Macroevolution
formation of a new species or groups of species
_____ can lead to ______
microevolution can lead to macroevolution
Species
group of related organisms that share a distinctive form
(if members reproduce sexually, they are capable of interbreeding to produce viable and fertile offspring)
Population
members of the same species that are likely to encounter each other and thus have the opportunity to interbreed.
Evolution is based on…
variation in a given species and natural selection
Theory of decent with modification
All life-forms are related (common ancestry)
New life forms derive from older forms (macroevolution)
Lineages split and diverge (speciation)
Species change over time (microevolution)
When put together, “Existing life forms result from the modification of pre-existing life forms.
What factors make species change?
Genetic variation and natural selection
Genetic variation
variation in the characteristics among individuals of a species and it is heritable.
Biogeography
the study of geographic distribution of extinct and living species (island species are a good example)
Convergent evolution
species from different lineages (different ancestors) have independently evolved similar characteristics due to similar environments. (Analogous structures/convergent traits)
Selective breeding/artificial selection
programs and procedures designed to modify traits in domesticated species (examples are dogs, crops, and farm animals)
Gene pool
All the alleles in a given population that could
potentially be passed to the next generation
Allele
A variant form of a gene
Gene
a gene is a functional piece of DNA
Genotype
The genetic composition of an individual
Population Genetics
The study of genes and genotypes in a
population
what is the Hardy-Weinberg equation?
p^2 + 2pq + q^2 = 1
What are the conditions that must be met for a population to be in Hardy-Weinberg Equilibrium?
Individuals:
-change as a result of mutations that originate new alleles
-pass their alleles to the next generation randomly
-some are more successful in surviving and reproducing
-surviving individuals have alleles that better adapt to their environment
What are the four processes that can change allele and genotype frequencies? (allows populations to evolve)
Mutation
Selection
Drift
Migration
Mutation
Change in the genetic material that is heritable. Low rate of occurrence and do not play a major role in changing allele frequencies in a population over time.
Natural Selection
when some individuals survive and reproduce at higher rates than others
Fitness
relative probability that one genotype will contribute to the gene pool of the next generation
Directional selection
favors ONE type of extreme phenotype (graph is skewed)
Stabilizing selection
favors intermediate values (normal curve)
Disruptive selection
opposite to stabilizing, extreme traits are favored (double hump curves)
Sexual selection
heritable traits that make an organism more successful at finding mates, than this trait will become more common