15.3 - Darwin Presents His Case

what book contained Darwin’s theories?

On the Origin of Species

what are heritable traits?

traits in genes that can be passed down to offspring

what is artificial selection?

humans using nature-given variations to make more useful offspring

what three factors drive natural selection?

struggle for existence, survival of the fittest, and descent with modification

what does the struggle for existence state?

that members of each species are forced to struggle for resources

what is fitness as defined by Darwin?

ability to survive and reproduce in environment

fitness is the result of ….

adaptations

what are adaptations?

inheritable characteristics that increase survival

stronger members of a species are more likely to _____ in the end

reproduce

difference between struggle for existence and survival of fittest?

struggle for existence focus on limited resources, while survival of fittest focuses on advantageous traits that lead to more being reproduced

what does descent with modification state?

natural selection makes organisms different from their ancestors

what is the common descent principle?

all living species come from a common ancestor

four types of evidence for evolution is…

fossil record, geography, homologous anatomy, and embryo

what does the fossil record prove about evolution?

that organisms have evolved over time

what does geographic distribution of living species prove?

that organisms with more favorable traits are more likely to survive

what does HOMOLOGOUS anatomy prove about evolution?

that all four-limbed vertebrates came from common ancestors

what are vestigial organs?

parts of body from ancestors that are no longer needed

what do similarities in embryos SUPPORT in proving evolution?

what homologous body structures prove