Evidence of Evolution-Animals Flashcards
What is so unique about the Galapagos?
first place natural selection documented in real time; owned by Ecuador
What did Darwin discover on the Galapagos that led him to the theory of natural selection?
31 specimens of finches similar except beak function; 14 species now recognized
What 3 things do you need in order for natural selection to be able to occur?
- genetic variation-variation must exist in population 2. reproductive success-variation must lead to differences among individuals in reproductive success 3. variation must be genetically transmitted to the next generation, heritable
What impact did Peter and Rosemary Grant have on natural selection?
studied medium ground finch on Daphne Major; found beak depth variation among members of the population
What happened with peppered moths?
when environment changes, natural selection often favors different traits in a species; body color is a single gene, black individuals have the dominant allele which were rare until 1850s and then frequency increased to near 100%
Who hypothesized that light-colored moths declined because of predation?
J. W. Tutt
What is artificial selection?
operates by favoring individuals with certain phenotypic traits, allowing them to reproduce and pass their genes on to the next generation, directional selection results in evolutionary change
What is domestication?
human-imposed selection (ex. cats, dogs, pigeons, and others)
What are the 3 events that occur when rock fossils are created?
organism buried in sediment, calcium in bone on other hard tissue mineralizes, surrounding sediment hardens to form rock
What are fossils?
preserved remains of once-living organisms
What is relative dating?
position of the fossil in the sediment
What is absolute dating?
age of fossils is estimated by rates of radioactive decay
What are isotopes?
transform at precisely known rates into radioactive forms
What is the half-life?
rate of decay, the amount of time needed for one-half of the original amount to be transformed
Why are there gaps in the fossil record?
low likelihood of fossil preservation and recovery
What is the Field of Systematics?
reconstruction and study of evolutionary relationships
What is phylogeny?
hypothesis about patterns of relationship among species
What did Darwin envision about species?
that all species were descended from a single common ancestor, depicted this history of life as a branching (“Descent with modification”)
What are cladistics?
study of characteristics of animals, use morphology to group organisms together
What is a derived characteristic?
similarity that is inherited from the most recent common ancestor of an entire group
What is an ancestral characteristic?
similarity that arose prior to common ancestor of the group
What are synapomorphies in cladistics?
shared derived characteristics are considered informative about evolutionary relationships
What are plesiomorphies?
ancestral states
What are symplesiomorphies?
shared ancestral states