Evolution - Unit 8 Flashcards
What was Lamarck’s theory of Evolution?
Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics (giraffe example)
What are the two main ideas about evolution that Darwin came up with?
- Descent with modification explains life’s unity and diversity
- Natural selection is a cause of adaptive evolution
What is artificial selection?
Selecting and breeding individuals with desired traits
What two observations did Darwin come up with about artificial selection, natural selection, and adaptation?
- MEMBERS OF A POPULATION OFTEN VARY IN THEIR INHERITED TRAITS
- ALL SPECIES CAN PRODUCE MORE OFFSPRING THAN THE ENVIRONMENT CAN SUPPORT, AND MANY OF THESE OFFSPRING FAIL TO SURVIVE AND REPRODUCE
What two inferences did Darwin come up with about artificial selection, natural selection and adaptation?
- Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals
- This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations
Overproduction of offspring leads to _____.
competition
Adaptations must be _____.
heritable
Darwin never used the word evolution he used the phase, _______.
Decent with modification
What does the phrase Decent with Modification refer to?
The phrase refers to the view that all organisms are related through descent from an ancestor that lived in the remote past
What is a Gene Pool?
all of the alleles of all of the individuals in a population
What is Allele Frequency?
a measure of how common an allele is in a population.
How do you calculate the allele frequency?
Calculate by taking (# of specific allele)/(total number of alleles in population) (part/whole)
Where does genetic variation come from? (2 places)
- Mutation
2. Recombination
What is recombination?
Crossing over during Meiosis.
What is microevolution?
observable change in allele frequency of a population over time (is small scale)
What is Directional Selection? (Natural selection)
An “extreme” phenotype that was once rare is now more common. The “mean” value of the trait shifts over towards the more advantageous trait.