Exam 3

Question 1

What is Biological evolution?

Answer 1

Change in the characteristics of a population of organisms that occurs over the course of generations

Question 2

Darwin and Evolution

Answer 2

Not the first to propose the idea of biological change (evolution) but He and Alfred Wallace were the first to propose the idea of Natural Selection.

Question 3

What is evolution (descent with modification)?

Answer 3

Species presently on the earth descended from a single common ancestor and have changed over time

Question 4

Natural Selection

Answer 4

Mechanism that drives evolution. Those individuals best suited to the environment survive and produce more offspring, driving (evolution) change over time

Question 5

What are alternative hypotheses?

Answer 5

Static model - Species arise separately and do not change over time

Transformation - Species arise separately and change over time in order to adapt to the changing environment

Separate types - Species change over time, and new species can arise, but not from a common ancestor. Each group of species derives from a separate ancestor that arose independently

Common descent - Species do change over time, and new species can arise. All species derive from a common ancestor

Question 6

What are a few examples for evolution?

Answer 6

Fossil record, Biogeography, Anatomical Homology, Developmental Homology, Molecular Homology, Suboptimal Structures, and Vestigial traits. To name a few

Question 7

What is tuberculosis?

Answer 7

Lung disease is caused by the bacterium Mycobacterium tuberculosis. It destroys lung’s ability to provide oxygen to the body. 1/3 of the world is affected, but most don’t get active TB. Spread almost entirely by people with active disease. 2 million die yearly because of it.

Question 8

What is Antibiotics?

Answer 8

Drugs that kill that bacteria. Must be given for 6-12 months.

Question 9

Antibiotic resistance

Answer 9

20% of TB don’t respond to standard antibiotics. 2% don’t respond to any. This is due to TB developing resistance to Antibiotics through mutation.

Question 10

The Four Observations of Natural Selection

Answer 10

1. Individuals within populations vary
2. Some variation can be passed to offspring
3. Populations overproduce
4. Survival and reproduction are not random

Question 11

Inference of Natural Selection

Answer 11

Natural selection occurs and drives evolution

Question 12

The Modern Synthesis

Answer 12

Random gene mutations produce variation, then there’s natural selection on that variation. Ultimately natural selection acts on the genes

Question 13

Misunderstanding of Natural Selection

Answer 13

For example the statement, “The Dodo was too stupid to adapt to human hunters, so it had to go extinct.
This would be false because the Dodo was not stupid or unworthy but it simply didn’t contain the variants with hunter-avoiding traits.

Question 14

Misconceptions about Natural Selection

Answer 14

individuals cannot evolve on purpose.
Natural selection does not produce ‘perfect’ organisms.
Natural selection does not have an end goal.

Question 15

How does one stop drug resistance?

Answer 15

Combination drug therapy - bacteria are very unlikely to be resistant to multiple drugs.
They don’t work on viruses, used for bacteria only.

Question 16

Biological species concept

Answer 16

A species is a group of individuals that, in nature, can interbreed and produce fertile offspring, but cannot reproduce with members of other species.

Question 17

How do new species form (speciation)?

Answer 17

Allopatric speciation - Geographic barrier separates populations
The population may change over time to become new species

Sympatric speciation - New species will originate with no geographic barriers between populations
Can occur when populations occupy a new niche
Reproduction requires reproductive isolations

Question 18

How long does speciation take?

Answer 18

Gradualism - modal says new species occur by the gradual accumulation of small changes across a long time.

Punctuated equilibrium - modal says species usually evolve relatively quickly, followed by long periods of stasis (no change). More often supported by the fossil record.

Speciation usually takes 10,000 to 100,000 years

Stasis is usually 5-10 million years

Question 19

What is a biological race?

Answer 19

Races are subspecies; populations of a single species that have separated from each other.
Members of a subspecies share ancestry, look more alike, and generally don’t mix with the others subspecies.

Question 20

What does the Fossil evidence of human evolution tell us?

Answer 20

Most evidence points to the ‘out of Africa’ hypothesis.
African populations are the most diverse, meaning they are the oldest.
Humans have little genetic diversity and are young as a species. The races cannot be that different from each other.

Question 21

Genetic Evidence

Answer 21

No alleles are found in all members of a race but not in other races
Populations within a race are often as different as populations compared across races

Question 22

Why do Human Groups differ?

Answer 22

Natural selection has favored certain traits in a similar environments

Question 23

Why do human groups differ?

Answer 23

Natural selection has favored certain traits in similar environments.

Question 24

Genetic drift

Answer 24

A change in allele frequency due to chance. Often seen in human population.
Examples:
Founder effect
Population bottleneck
Chance events in small populations

Question 25

Sexual selection

Answer 25

When traits influence the likelihood of mating. Hairlessness in some human groups is an example.

Question 26

Assortative mating

Answer 26

Tendency of organisms to mate with individuals that are like them in some respect.

Question 27

Racial categories

Answer 27

They have been used to justify racism and fight discrimination. They are however meaningless.

Question 28

Reasons growth rate had soared

Answer 28

• Improved medical care, including immunizations and antibiotics
• Improved sanitation
• Improved nutrition through industrial agricultural techniques

Question 29

What countries have passed through the demographic transition? (death rate drops while birth rate is the same)

Answer 29

Developed countries (USA, France, Japan, etc….)

Question 30

What is a populations limit in terms of growth?

Answer 30

Carry capacity

Question 31

What are the factors affecting growth?

Answer 31

Density-dependent - Food, water, shelter/place to live, spread of disease, accumulation of waste

Density independent - Weather fluctuation, natural disaster

Question 32

Demographic momentum

Answer 32

The young population will continue to swell.

Question 32

How can we decrease growth rates?

Answer 32

Improve female literacy - which delays reproduction