Evolution Notes

Understanding Evolution:

Notes:

Darwin and Wallace described the mechanism for evolution

Darwin developed the idea of natural selection, or survival of the fittest

• Most characteristics of organisms are inherited
• More offspring are produced than are able to survive
• Offspring vary in characteristics

Natural selection can only take place if there is variation. These will be spread through mutations and reproduction

Adaptation is a new trait that helps an organism survive

Divergent evolution is the point of change for two species

Biogeography causes different types of evolution to occur to different organisms

Questions 1-8:

1. c

2. b

3. a

4. d

5. Whichever seeds are capable of growing into plants through the more difficult parts of survival demonstrate natural selection.

6. Because they are similar among completely different species - organisms for that matter

7. A theory means tested multiple times without failure

8. A monkey seems more advanced, because of its human-like characteristics. However, they mouse is just as evolved but in a different way.

Formation of New Species:

A species is a group of individual organisms that interbreed and produce fertile, viable offspring

The closer an organism is in species, the more DNA they will have in common

A hybrid is a cross between two species

Many species can create fertile offspring-hybrids

For species to be made, they need to evolve to the point where they cannot interbreed with any other species successfully 

Allopatric speciation is evolution due to change in location

• Dispersal is a simple movement
• Vicariance is a forced geographical change

Sympatric speciation is evolution in the same location

• Mutation
• Aneuploidity is a change in number of chromosomes
• Polyploid is extra

Reproductive isolation

• Prezygotic barrier
• temporal isolation (breed time)
• Behavioral isolation
• Habitat isolation
• Gametic barrier

Questions 1-8:

1. 2n + 1

2. a

3. b

4. b

5. c

6. c

7. c

8. d

Reconnection and Rates of Speciation:

A hybrid zone is where different species that can interbreed create hybrids

• Reinforcement is when the hybrids move away from each other
• Fusion is when the hybrids become one species
• Stability is when the hybrids continue to be produced

Gradual speciation is when species diverge gradually over time in small steps

Punctuated speciation is when a new species undergoes changes quickly from the parent species

Environment has the most effect on speciation

Questions 3 - 4

3. a

4. c

Population Evolution:

Modern synthesis is how natural selection plays a part in speciation

Microevolution is a change in a population’s genetic structure

Macroevolution is evolutionary changes on a broader scale

Gene pool is the sum of all alleles in a population