Chapter 22 Flashcards
ideas of Hutton and Lyell
gradualism
gradualism
change can take place through slow and continuous processes
Lamarck’s ideas
species evolve through use and disuse of traits
What did Darwin observe on the Beagle?
adaptations of plants and animals to their diverse environments
geographic distribution
Darwin’s 2 main ideas
evolution explains life’s unity and diversity
natural selection is a cause of adaptive evolution
descent with modification
organisms are related through descent from a common ancestor
Darwin’s first 3 observations about Natural Selection
- Population size increases if all individuals reproduce successfully
- Populations are stable in size
- Resources are limited
Darwin’s first 3 observations of natural selection led to what inference?
Inference 1:
More individuals in an environment leads to a struggle for existance
Darwin’s 4th and 5th Observations about natural selection
- No two individuals in a population are exactly alike
5. Much of the genetic variation is heritable
Darwin’s 2nd inference
survival depends on inherited traits
individuals who have successful traits are more likely to survive
Darwin’s 3rd inference
the unequal ability of individuals to survive and reproduce leads to a change in a population
favorable characteristics accumulate over generations
3 main points about natural selection
- NS is differential success in reproduction from interaction between individuals and their environment
- NS produces an increase of adaptation overtime
- NS may result in adaptation to new environmental changes
2 examples of natural selection
differential predation of guppy population
evolution of drug-resistant HIV
homology
similarity resulting from common ancestry
genes shared from a common ancestor
biogeography
the geographic distribution of species
