Natural Selection (2/7)

Question 1

Thomas Malthus’s “Principle of Population”

Answer 1

Malthusian Theory: predicts population size increases and a geometric rate but there must be some sort of check to prevent insane amount

• think the Chess Board multiplying example

Question 2

First Papers on Natural Selection (by Darwin and Wallace)

Answer 2

• both arrived at the same conclusion of Natural Selection but Darwin received most of the credit for the idea

Question 3

Origin of Species

Answer 3

Darwin’s book

• provided the central tenets of evolution by natural selection

Question 4

Three Requirements for Natural Selection

Answer 4

1. ) Variation: offspring are NOT exact copies of parents (mutations and mixing of genes)
2. ) Inheritance: offspring inherit combination of traits from parents
3. ) Differential Reproduction: individual with any slight adaptive edge has greater chance of producing offspring

**4.) Overpopulation: many more offspring produced than can survive (this isn’t necessarily one but it is an important factor)

Question 5

Genotype

Answer 5

internally coded, inheritable information carried by all life that is the “blueprint” or set of instructions for building and maintaining a living organism

Question 6

Allele

Answer 6

the variant form of a given gene

Question 7

Phenotype

Answer 7

the outward, physical manifestation of the genotype;

the set of observable characteristics of an individual resulting form the interaction of its genotype with the environment

Question 8

Ecophenotype

Answer 8

morphological changes caused by varying environmental-nutritional conditions rather than genetic differences

• not heritable so it doesn’t play a direct role in natural selection

Question 9

Fecundity

Answer 9

the ability to produce an abundance of offspring

Question 10

Types of Natural Selection

Answer 10

1. ) Stabilizing Selection
2. ) Directional Selection
3. ) Disruptive/Diversifying Selection
4. ) No Selection/Drift

Question 11

Stabilizing Selection

Answer 11

selection against the extremes in a population; results in the maintenance of the status quo around an optimum

• i.e. timing of spawning, mating calls in frogs, flowering
• can decrease variability within a population

Question 12

Directional Selection

Answer 12

a type of selection where a single phenotype is favored

• causing the allele frequency in the population to shift in one direction over time
• i.e. the color of desert mice,

Question 13

Disruptive/Diversifying Selection

Answer 13

the selection for extremes in a population

• i.e. the color of fur in Himalayan rabbit fur

Question 14

No Selection/Drift

Answer 14

no differential reproduction; all forms are equally successful