Chapter 4: Evolution

Question 1

Define: Divergent Evolution

Answer 1

increases differences between species as a result of living in [slightly] different environments

Question 2

Define: Convergent Evolution

Answer 2

decreases differences between [unrelated] species as a result of adapting in similar environments

Question 3

Define: Mutation

Answer 3

Accidental changes in DNA

Question 4

Allopatric Speciation

Answer 4

When new species are generated as a result of the same species being separated into different geographical locations

Question 5

Directional selection

Answer 5

When a trait is driven in one direction(ex. if all snails adapt to have thick shells)

Question 6

Stabilizing Selection

Answer 6

When a intermediate trait is favoured(ex. all snails adapt to have shells of intermediate thickness)

Question 7

Disruptive Selection

Answer 7

When traits diverge in two or more directions(ex. some snails have thick shells, some have thin shells)

Question 8

Sympatric Speciation

Answer 8

When species from populations become reproductively isolated within the same area(ex. species mating at different seasons)

Question 9

Phylogenetic Trees

Answer 9

Diagrams representing the divergence and relationship between species, and how certain traits have evolved.

Question 10

What is the average time a species tends to exist on Earth?

Answer 10

1-10 million years

Question 11

Extirpation

Answer 11

Local extinction

Question 12

What does it mean for a species to be ENDEMIC to a region?

Answer 12

Endemic species only exist in one region on Earth

Question 13

What constitutes a mass extinction?

Answer 13

when 50-95% of all species on Earth go extinct within a relatively short amount of time

Question 14

What mass extinction are we currently living in?

Answer 14

6th- Anthropocene

Question 15

When did the mass extinction of the dinosaurs occur?

Answer 15

~66 million yrs ago

Question 16

Ecosystem

Answer 16

communities and the nonliving material and forces they interact with

Question 17

Biosphere

Answer 17

All the living things on earth and the areas they inhabit

Question 18

What was the largest mass extinction?

Answer 18

Permian-Triassic ~252 mya

Question 19

define: cell

Answer 19

The smallest unit of living
matter able to function
independently, made up of organelles

Question 20

List the hierarchy of matter within organisms from smallest to largest: organ system, organism, molecule, tissue, organelles, atom, organ, macro-molecule

Answer 20

atom, molecule, macro-molecule, organelle, cell, tissue, organ, organ-system, organism

Question 21

What is the distinction between a community and a population?

Answer 21

Community consists of all the different species living within a region, a population is only one species

Question 22

What is a species’ NICHE?

Answer 22

the species use of resources and functional role within a community(habitat use, food selection)

Question 23

Community Ecology

Answer 23

focuses on interactions among species

Question 24

Population Ecology

Answer 24

investigates the quantitative dynamics of how individuals within a species interact

Question 25

Ecosystem Ecology

Answer 25

studies living and nonliving components of systems to reveal patterns

Question 26

Define a SPECIALIST(with regards to species)

Answer 26

A species that has a very specific niche, usually very good at what they do but are vulnerable to change

Question 27

Define a GENERALIST(with regards to species)

Answer 27

A species with a very broad niche, able to live in many different habitats/environments

Question 28

What are the benefits/drawbacks of HIGH vs. LOW density population of a species?

Answer 28

High: Easier to find mates, but more competition, vulnerability to predators, and more likely to catch disease LOW: Harder to find mates, but can leave with more space and resources

Question 29

What are the three different types of population distribution? Which one is the most common in nature?

Answer 29

Random: individuals are located haphazardly in space with no specific pattern(not common) Uniform distribution: individuals are evenly spaced.(occurs when individuals hold territories or otherwise compete for space) Clumped distribution: organisms arrange themselves according to the availability of the resources they need to survive (MOST common)

Question 30

Define: Crude birth/death rate

Answer 30

Number of births/deaths per 1000 individuals in a given time frame

Question 31

What are the three fundamental types of survivorship curves?

Answer 31

Type 1: Higher death rates at OLDER ages (eg. Humans) Type 2: EQUAL death rates at ALL ages (Eg. birds) Type 3: Higher death rates and YOUNG ages (eg. Frogs)

Question 32

What four factors determine population growth/decline?

Answer 32

1. NATALITY: Births within population 2. MORTALITY: Deaths within population 3. IMMIGRATION: Arrival of individuals 4: EMIGRATION: Departure of individuals

Question 33

Exponential Growth

Answer 33

Population grows at a fixed percentage each year

Question 34

Logistical growth curve

Answer 34

S-shaped curve; rises sharply at first but then begins to level off as the effects of limiting factors(eg. carrying capacity) become stronger

Question 35

Biotic Potential

Answer 35

The maximum capacity to produce offspring under ideal environmental conditions(ex. fish that can lay many eggs at a time have HIGH biotic potential)

Question 36

K-selected species

Answer 36

Species that reproduce SLOWLY, long gestation periods(eg. whales)

Question 37

R-selected species

Answer 37

Species that reproduce QUICKLY, high biotic potential(think R... Rapid)