evolution Flashcards
evolution
a change in a species over time, usually as a result of natural selection
darwin’s observations
A single species can be very diverse as offspring inherit many traits
Species can develop useful traits over generations
Increasing populations bring about more competition
Produce more because fewer offspring survive
Children inherit helpful traits
natural selection/survival of the fittest
organisms that are better adapted to their environment survive and reproduce while those who aren’t adapted die off.
adaptation vs variation
a variation is a change in the genetic code, an adaptation is a variation that aids species survival
genetic diversity
changes/multiple different traits in the genetic code, comes from mutations and reproduction
homologous structures
similar structures in related organisms that imply a common ancestor
analogous structures
similar structures that do not develop from the same tissue
genetic drift
survival of the luckiest/random changes in the gene pool
founder effect
isolated populations having a stronger population of certain genes than non-isolated populations, because populations with low genetic diversity reproduce in only one location
bottleneck effect
when a species has a dramatic decrease in population size, genetic diversity decreases, so when the population size increases genetic diversity is still low
fossil record
shows that species changed over time because fossils back then look different from fossils now
similarities in embryos
common traits originating from common ancestors but evolving to fit current conditions
genetic information to determine common ancestors
looking at the number of differences in the DNA of certain species to see how closely related they are and how recent their common ancestor is
three types of adaptations
structural - changes in physical structure
behavioral - changes in behavior
physiological - changes in chemicals/cells (usually unconscious to the organism)
vestigial structure
structures that are no longer used by an organism. they show a trait that a species once had but evolved to not need
