Chapter 8

Question 1

A populations density is calculated as the…

Answer 1

number of individuals per unit area

Question 2

How might a species’ range be extended?

Answer 2

through climate change

Question 3

The sex ratio of human senior citizens (>65 years) is…
a. 1:1
b. skewed towards females
c. the same as birds’
d. skewed towards males

Answer 3

skewed towards females

Question 4

Which of the following represents a modular organism?
a. coral
b. dog
c. lizard
d. ant

Answer 4

Coral

Question 5

Which of the following sampling techniques represents an index of abundance rather than an estimate of density?

Answer 5

number of bear droppings along a trail

Question 6

The demographic age pyramid of a rapidly growing population is…

Answer 6

wide at the base, narrow at the top.

Question 7

Why is Pacific salmon movement into freshwater streams considered migration if the salmon die at the head of the stream and never return to the ocean?
a. It is not migration but immigration
b. Most male adult is survive reproduction and return to the ocean
c. Migration is a one-way movement
d. Because their offspring returns to the ocean, so the entire population participates in the migratory event via different life stages.

Answer 7

Because their offspring returns to the ocean, so the entire population participates in the migratory event via different life stages.

Question 8

If more individuals move out of a forest than into it every year, the ____ rate is high

Answer 8

emigration

Question 9

A module that is produced asexually by an original genetic individual, which may either remain physically linked to the parent or may be separated, is referred to as a(n)…..

Answer 9

Ramet

Question 10

Calculate the estimated population size (N), given a study that initially marked 100 animals and subsequently captured 50, of which 25 were already marked.

Answer 10

N = 200

Question 11

Define population

Answer 11

Group of individuals of the same species that inhabit a given area. Populations have structure, are dynamic, and change over time.

Question 12

Define distribution

Answer 12

The area over which the population occurs

Question 13

Define geographic range

Answer 13

The range of which an individual of a species can live.

Question 14

What is geographic range limited by? (give 4 examples)

Answer 14

A species tolerance to different environmental conditions (temperature soil moisture, elevation, geographic barriers).

Question 15

Define ubiquitous species

Answer 15

Species with a geographically widespread range/distribution

Question 16

Define endemic species

Answer 16

Species with a geographically restricted distribution. Many have specialized habitat requirements. High rate of extinction.

Question 17

Why aren’t organisms distributed equally across a geographic range?

Answer 17

Organisms are found within suitable habitats within that range. The environment is heterogeneous, so some habitats are suitable and others are not within this range.

Question 18

How are populations divided into subpopulations while remaining connected?

Answer 18

Populations are divided into subpopulations that live in suitable habitat patches surrounded by unsuitable habitats. These subpopulations are spatially separated but connected by the movement of individuals between them (immigration/emigration).

Question 19

Define metapopulation

Answer 19

Collection of local subpopulations

Question 20

Define abundance

Answer 20

Defines the size of a population (# of individuals).
A function of population density and the area over which the population is distributed.

Question 21

What is a quadrat?

Answer 21

A grid search for population distribution

Question 21

What is Crude Density? and what is the metric for it?

Answer 21

The number of individuals per unit area. Use m2, km2, or kL, L.

Question 22

How do you perform a quadrat?

Answer 22

Place a grid over an area. Find the amount of an organism within this grid and calculate the density based on the area of the grid.

Question 22

Which test is better for determining plant density? animal density?

Answer 22

Plant - quadrat
Animal - mark-recapture

Question 23

Define random distribution

Answer 23

Position of one individual is independent on the position of another individual *quadratting works very well for this type

Question 24

Define uniform distribution

Answer 24

Organisms are found at a regular distance from one another

Question 25

Define clumped distribution

Answer 25

Individuals are found in groups. The presence of one individual predicts the presence of another.

Question 26

Define ecological density. What is a downside of it?

Answer 26

Number of individuals per unit of available living space. Helps to account for patchy distributions of some species. Downside - difficult to determine what part of a habitat is living space for a specific species.

Question 27

Population abundance formula

Answer 27

Population abundance = (population density) x (area occupied)

Question 28

What is the mark-recapture method?

Answer 28

Capture a number of individuals in a population within x amount of time. Mark them. After an appropriate period of time, capture a number of individuals within the same amount of time. Of the individuals captured the second time, some will have been marked or recaptured. Use the numbers to determine population density

Question 29

What is the formula of mark-recapture and what the variables mean?

Answer 29

N = nM/R N = Population size M = originally captured individuals n = total individuals captured on 2nd trip R = individuals recaptured on 2nd trip

Question 30

What are the 3 cohorts a population can be divided into?

Answer 30

Pre-reproductive Reproductive Post-reproductive

Question 31

How can we determine their relative age of death? (what do we look at)

Answer 31

- wear of teeth / teeth replacement - growth rings in teeth or horns - plumage changes/ wear&tear of plumage in birds - annual growth rings

Question 32

What do the pyramids of the 3 age distributions look like?

Answer 32

Positive growth rate - pyramid with a wide base - represents growing population negative growth rate - pyramid with a narrow base - represents dying population no growth rate - equal base to top - represents static population

Question 33

How does the sex ratio shift for organisms throughout life? (birth - post-reproductive)

Answer 33

Sex ratio at birth is slightly shifted towards males (1.07:1) but shifts towards females in older age.

Question 34

Why do males generally have a shorter lifespan than females?

Answer 34

Males typically have rivalries for resources/mates, resulting in a greater likelihood of death

Question 35

Define dispersal

Answer 35

Movement of individuals in space

Question 36

Define emigration / immigration

Answer 36

emigration - individuals exit a subpopulation immigration - individuals join a subpopulation

Question 37

Define passive & active dispersal

Answer 37

Passive - abiotic factors move individuals Active - individuals move themselves