Exam – Evolution

Question 1

Scientists and Their Contributions to Evolution

Answer 1

George-Louis Leclerc
- Challenged the idea that life never changed, introduced first concepts of evolution

George Culver
- Catastrophism
- Thought that the earth had many catastrophes which killed lots of species, often on the edges of rock boundaries (tectonic plates)

Charles Lyell
- Uniformatism
- Said that geological process have always been happening at the same, very slow rate.

Jean-Baptiste Lamarck
- Inheritance
- Said that organisms adapt to the env. over time, but thought that aquired traits were passed down
- EX. Parent with burned hand scar would have child with scar too

Darwin & Wallace
- Evolution through natural selection

Question 2

Natural Selection

Answer 2

Change that happens over many generations; surviving individuals pass their traits on to offspring

Question 3

Selective Pressures

Answer 3

Env. conditions that select for certain traits and not others

Question 4

Mimicry

Answer 4

A harmless species evolving to look like a harmful one to scare off predators

Question 5

Species Variations

Answer 5

Structural, functional, or physiological differences between organisms

Question 6

Evidence of Evolution

Answer 6

Paleontology
- Fossils; remains of an organism or evidence of its presence

Comparitive Anatomy
- Looking for structures that are similar between species

Embryology
- Similarites in embryo development between organims

Comparitive Biochem.
- Comparing DNA & amino acid base sequcences between organisms

Geographical Distribution
- Natural geographic distrubution of species on the earth

Question 7

Paleontology

Answer 7

• Study of fossils & their age
• FOSSILS – Remains of an organism or evidence of its presence
• The deeper the fossil, the older

Question 8

Behavioral Isolating Mechanism

PRE ZYGOTIC

Answer 8

• Behavior or routine that stops a species from breeding
• EX. Bird species having different mating calls

Question 9

Habitat Isolating Mechanism

PRE ZYGOTIC

Answer 9

• When two species live in different habitats in the same general area
• Physically blocked from interacting
• EX. Fish and land bugs

Question 10

Temporal Isolating Mechanism

PRE ZYGOTIC

Answer 10

• When species mate at different times or parts of the year, limiting interaction
• EX. tulips bloom in spring, roses bloom in mid summer

Question 11

Mechanism Isolating Mechanism

PRE ZYGOTIC

Answer 11

• Closely related species who’s genital anatomy are phycially incompatible
• Common in insects

Question 12

Gametic Isolating Mechanism

PRE ZYGOTIC

Answer 12

• Gamete is not able to survive in the harsh env. of the female’s reproductive tract

Question 13

Hybrid Inviability

POST ZYGOTIC

Answer 13

• Genetic info is not compatible within the species
• Zygote is not able to undergo mitosis

Question 14

Hybrid Sterility

POST ZYGOTIC

Answer 14

• When two species can mate & produce viable offspring
• Offspring are sterile, cannot do meiosis

Question 15

Hybrid Breakdown

POST ZYGOTIC

Answer 15

• Two organisms are able to mate and produce viable & fertile offspring
• When hybrid offspring mate, their offspring are sterile & weak

Question 16

Stabilizing Selection

Answer 16

• Natural selection that favours average pheotypes, doesn’t like extreme variations
• Reduces variaiton, improves adaptation of population to aspects of env. that remain constant

ex. bird egg size & number laid

Question 17

Directional Selection

Answer 17

• Natural selection that favours phenotypes of one extreme over the other, or the average.
• Common during changes of the living env.

ex. more peppered moths being black during the industrial revolution due to soot, becoming white more often after anti-pollution laws

Question 18

Disruptive Selection

Answer 18

• Natural selection that favours the extremes of a range of phenotypes rather than the average.
• No more average. Either extremely A trait or extremely B trait

ex. squirrels with long tails for balance, also ones with short tails to avoid being caught by predators

Question 19

Artificial Selection

Answer 19

Selective pressure made by humans which force a population to change to different traits (usually on purpose)

Question 20

Sexual Selection

Answer 20

When females in a species choose the most fit male (to make good offspring)

Question 21

Non-random Mating

Answer 21

Mating where individuals are more likely to mate with individuals with certain genotypes/phenotypes

• Can cause inbreeding

Question 22

Homologous Structures

Answer 22

Body parts in species that have the same evolutionary origin, but serve different purposes

Question 23

Analagous Structures

Answer 23

Different structures that have a common purpose in unrelated species

Question 24

Vestigial Structures

Answer 24

A structure that is a reduced version of one that was functional in previous generations

Question 25

Gene Flow

Answer 25

Movement of alleles from one population to another b/c of migration ## Footnote ex. a grey wolf going really far in search of a mate and brining his fur color over to a different color of wolves

Question 26

Genetic Drift

Answer 26

Change in distribution of alleles in a population due to a chance event **Founder Effect** - new population formed by a few individuals with limited diversity **Bottleneck Effect** - changes in gene distribution due to rapid decrease in population size

Question 27

Mutations

Answer 27

Random change in genetic material of an organism, causing genetic variation

Question 28

Gene Pool

Answer 28

All of the genes of all of the individuals in a population

Question 29

Population

Answer 29

A group of individuals of the same species in a specific area, at a specic time

Question 30

Species

Answer 30

A group of organism that can interbreed in nature, producing fertile offspring

Question 31

Allele Frequency

Answer 31

The number of copies of an allele compared to the total number of alleles in a population

Question 32

Microevolution

Answer 32

Occurs when the frequency of alleles changes