Final Exam Flashcards
Evolution =
the theory that all life on earth descended from a common ancestor with modifications of genetic material leading to different types of organisms
Linnaeus believed -
species did not change over time (immutable)
Lamarck believed -
an individual may develop certain traits that it passes on to its offspring
Natural selection -
The process through which the most fit individuals pass on their genes to the next generation
Darwin and Wallace proposed that -
present day species are the descendants of ancient ancestors that they still resemble in some ways
Who proposed natural selection? -
Darwin
Evidence of evolution
-Animals are very similar- think about early stages of embryos OR
similar skeletal structure (homologous structures)
- DNA and/or RNA as genetic blueprint
- Geography of similar animals (continental drift)
- Direct observation, like antibiotic-resistant bacteria (within 30 years)
-fossils
Fossils
document differences between - past and present organisms
Daphne Major island in 1977-
reduced the number of small seeds available to finches, causing many of the small beaked finches to die. This caused an increase in the finches’ average beak size to be between 1976 and 1978
Be able to analyze and interpret Evolutionary Trees
The ancestors are located at each branching point in the tree (nodes). Each node represents the most reacent common ancestor of all the branches coming off of it. Nodes that are farther away from the tips of the treee represent older ancestors. Do not count the steps. COMPARE THE MOST RECENT COMMON ANCESTORS
Selective Pressures
forces which favor certain traits and decide which organisms pass their genes to the next generation
Natural Selection
The process through which the fittest individuals pass on their genes to the next generation
Genetic mutation is the source of -
new adaptions and variations within a population.
Sexual Selection
Selection of traits with no apparent use besides attracting mates
Why is variation allowed?
because most traits are not under any (or under very limited) selective pressure most of the time