Heredity: Natural Selection Flashcards
1
Q
Variation
A
- crossing over (prophase I)
- independent assortment of chromosomes metaphase I &II)
2
Q
Why variation is impt
A
- mutation provide new alleles to gene pool for genetic variation to act on
- impt to help organisms adapt & survive
- changing environments
3
Q
Define natural selection
A
- process that ensures best adapted organisms in population survive
- reproduce, pass on genes to next gen
4
Q
What nature selects
A
- varieties of organisms that are:
- more resistant to diseases
- btr adapted to changes in environment
5
Q
Define evolution
A
- simple ancestral forms
- to complex forms of living
6
Q
Define adaptive evolution
A
- common ancestor
- evolve into several diff species
- each adapted to particular environment niche
- e.g. Galapagos finches
7
Q
Darwin’s observations of finches
A
- reproduce rapidly, compete for food
- variations occurred, diff finches with diff beaks suited for particular diet on island
- selected for by environment
- those selected survived, reproduced successfully
8
Q
Mechanism of evolution
A
- organisms reproduce rapidly due to abundant food supply
- migrate to diff environments
- spontaneous mutation occurs, result in variation
3a. favourable traits granted selective advantage, such organisms survive, reproduce, pass onto next gen - these organisms become predominant species in environment
9
Q
Artificial selection
A
- plants and animals with favourable traits
- artificially selected thru selective breeding
10
Q
How they occur (Natural vs artificial)
A
N: mutations in gene, brought abt by changes in environment
A: manipulation by humans (selective breeding) , humans select organisms with desired traits to reproduce
11
Q
Speed of process (Natural vs artificial)
A
- N: v slow
- A: relatively faster
12
Q
Effects on man (Natural vs artificial)
A
- N: may be advantageous or harmful
- A: advantageous
