Chapter 1: 1.2 The Modern Synthesis

Question 1

What is the modern synthesis?

Answer 1

Combines two important theories in biology
* Darwinian evolution and natural selection
* Mendel’s theory of inheritance

Question 2

What does Malthusian competition encompass?

Answer 2

• Geometric population growth
• Limited resources

Question 3

What does variation encompass?

Answer 3

• Breeds
• Races
• Subspecies

Question 4

What does mutations encompass?

Answer 4

Small changes in individual characteristics

Question 5

What does Natural selection encompass?

Answer 5

“Survival of the fittest”

Question 6

What does genetic variation encompass?

Answer 6

• Alleles of individual genes
• Combining to give continuous variation

Question 7

What does Mendelian inheritance encompass?

Answer 7

• 2 copies of each gene
• 1 from each parent

Question 8

Map out:

Modern synthesis

Answer 8

Natural selection (Malthusian competition + Variation) + Mutation (Genetic variation + Mendelian inheritance) = Modern synthesis

Question 9

State the contributions of:

Fischer and Haldane (1918-1930)

Answer 9

• Fisher in 1918 described how variation could result from discrete genetic loci
• Haldane in 1920 provided real world examples based in math

Question 10

In Fisher and Haldane (1918-1930):

What did Haldane discover in 1920?

Answer 10

The variation that could result from discrete genetic loci occurs faster than thought (E.x. Pepper moths in the industrial revolution)

Question 11

State the contributions of:

Wright (1932)

Answer 11

• Demonstrated how combinations of genes interacted to produce phenotypes
• Introduced adaptive fitness landscapes
• Investigated how small populations were at risk of inbreeding depression

Question 12

In Wright (1932):

What are adaptive fitness landscapes?

Answer 12

Combinations of genes can produce optimum trait values

Question 13

In Wright (1932):

What can small populations increase the chance of?

Answer 13

Increased chance of genetic drift
* Also at risk of inbreeding depression

Question 14

State the contributions of:

Dobzhansky (1937)

Answer 14

• Described natural populations by new mathematics
• Introduced chromosomes
• Identified main sources of evolutionary change

Question 15

In Dobzhansky (1937):

Describing natural populations by new mathematics…

Answer 15

• Was easier to understand
• Natural populations had lots of standing variation

Question 16

In Dobzhansky (1937):

In chromosomes…

Answer 16

Some regions are linked to each other

Question 17

In Dobzhansky (1937):

What were the main sources of evolutionary change identified?

Answer 17

• Mutations
• Chromosome rearrangement
• Multi-gene effects during development
• Polyploidy

Question 18

Define:

Polyploidy

Answer 18

Gene duplication

Question 19

State the contributions of:

Huxley (1942)

Answer 19

• Coined the term “Modern Synthesis”, helped to popularize
• Provided many examples to convince the public

Question 20

State the contributions of:

Mayr (1942)

Answer 20

• Examined how population variation led to speciation
• Described allopatric speciation
• Defined the biological species concept

Question 21

Define:

Allopatric speciation

Answer 21

When two populations are divided, evolve and become separate species

Question 22

Define:

Biological Species Concept

Answer 22

A group of interbreeding populations that do not breed with others