Module 2 - Natural Selection

Question 1

Aristotle’s “the chain of being”

Answer 1

Living world is unalterable; ladder of life

Question 2

Age of Enlightenment

Answer 2

Earth was older than initially believed!

Question 3

Jean-Baptiste Lamarck

Answer 3

• diversity of life shows the age of earth
• adaptation is a primary product of evolution
• WRONG - acquired traits can be passed down, used structures get bigger and vice versa

Question 4

Charles Lyell

Answer 4

Principles of Geology; earth has been shaped by slow action of rivers, earthquakes etc.

Question 5

Charles Darwin

Answer 5

“Decent with modification” - natural selection is a driving force in evolutionary change

Question 6

Darwins core concepts

Answer 6

All species have the ability to overproduce
Resources are limited -> struggle for survival
Individuals less suited for the environment are less likely to survive

Question 7

Natural Selection

Answer 7

Individuals have certain inherited traits tend to survive and reproduce better because of those traits

Question 8

What is changing in populations over time?

Answer 8

Allen frequencies of a gene pool

Question 9

Gene

Answer 9

A unit of heredity transferred from parent to offspring

Question 10

Gene pool

Answer 10

All genetic information in the individuals population

Question 11

Allele

Answer 11

1+ variants of a gene

Question 12

DNA

Answer 12

Molecule carrying genetic instructions of all known organisms

Question 13

Evolution

Answer 13

A change in allele frequencies in a gene pool

Question 14

What is changing in evolution

Answer 14

DNA (physical/behavioral characteristics); alleles

Question 15

4 mechanisms of evolutionary change

Answer 15

• mutations
• gene flow
• genetic drift (chance events)
• natural selection

Question 16

Mutations

Answer 16

Random events; can be beneficial, harmful, neutral

Question 17

Ways mutation can occur (2)

Answer 17

Spontaneous - a result of biological and chemical process
Induced - external factors (ex. Radiation)

Question 18

Gene flow

Answer 18

Exchanges alleles between two different populations (can introduce or remove alleles from a given population) *homogenizing force

Question 19

Genetic drift

Answer 19

Chance events cause unpredictable fluctuation in gene frequencies (impactful in small populations)

Question 20

Founder effect

Answer 20

When a small part of a larger population is established

Question 21

Population bottleneck (genetic drift)

Answer 21

Sharp reduction in size of a population; can reduce genetic variation

Question 22

Natural selection types (3)

Answer 22

Directional, stabilizing, disruptive

Question 23

Directional selection

Answer 23

Individuals with an advantageous trait that leans towards one extreme

Question 24

Stabilizing selection

Answer 24

Individuals with an average inherited trait are advantageous

Question 25

Disruptive selection

Answer 25

Individuals with either extreme of an inherited trait are advantageous

Question 26

Sexual selection

Answer 26

Traits which are good at securing a mate are over-represented (peacock feathers)

Question 27

6 lines of evidence for evolution

Answer 27

- fossils - traces of evolutionary history in existing organisms - similarities and differences in DNA - direct observations of genetic change in populations - the distribution of organisms and fossils around the world - present day formation of new species

Question 28

Homologous traits

Answer 28

Traits shared between groups of organisms because of their decent from a common ancestor

Question 29

Vestigial structures

Answer 29

Body parts that had served a purpose in ancestral species but currently not useful

Question 30

Convergent evolution

Answer 30

When natural selection causes similar phenotypic structures not due to a common ancestor

Question 31

Analogous traits

Answer 31

Traits shared between organisms because of convergent evolution

Question 32

Macro evolution

Answer 32

Evolution above the species level

Question 33

Micro evolution

Answer 33

Smaller evolutionary changes (alleles within a species or population)

Question 34

Speciation

Answer 34

When one species becomes a new species, reproductively isolation

Question 35

Pre-zygote barriers (5)

Answer 35

- temporal - ecological/habitat - behavioral - mechanical - gametic

Question 36

Post-zygote barriers (3)

Answer 36

- zygote death - hybrid infertility Hybrid breakdown

Question 37

Allopathic speciation

Answer 37

Geographical isolation

Question 38

Sympathize speciation

Answer 38

Hybrids (not geographical); individuals of the same population become different over time