Ch.53 Population Ecology

Question 1

Changes in population come from

Answer 1

Births, immigration
Deaths, emigration

Question 2

A group of individuals of a single species living in the same general area. The boundaries are either natural or defined by an investigator.

Answer 2

Population

Question 3

Density

Answer 3

the # of individuals per unit area/ volume

Question 4

Dispersion

Answer 4

pattern of spacing among individuals within boundaries of the population.

Question 5

Why do scientists use the mark-recapture method

Answer 5

It’s impossible/ impractical to count all the individuals

Question 6

3 patterns of dispersion (most to least common)

Answer 6

Clumped
Uniform
Random

Question 7

Clumped dispersion

Answer 7

most common. due to environments mating behavior, defense in numbers

Question 8

Uniform dispersion

Answer 8

secretion of chemicals, germination, territoriality.

Question 9

Random dispersion

Answer 9

least common. each individual is independent and occurs bc of the absence or strong attractions/repulsions

Question 10

Demography

Answer 10

study of key characteristics of populations and how they change overtime

Question 11

Life table

Answer 11

summarizes survival and reproductive rates of individuals in specific age groups in a population. Usually uses females. Presented in a chart/graph
-Age
-Number alive at start of yr
-Death rate
-Average number female offspring per female

Question 12

Cohort

Answer 12

group of individuals of same age

Question 13

Survivorship curve

Answer 13

plots of a proportion/ numbers in a cohort still alive at each age.

Question 14

Type I curve

Answer 14

flat at the start reflecting low death rates and early to middle life drops steeply as death rates increase in elders. (mammals). Low mortality

Question 15

Type II curve

Answer 15

Constant death rate

Question 16

Type III curve

Answer 16

Contrasts I. drops sharply at the start and evens out. common in organisms that produce lots of offspring with little care. Survivors live longer

Question 17

Reproductive rates

Answer 17

for sexual organisms measured as average number of female offspring produced by females in an age group

Question 18

If a population ecologist can’t locate organisms themselves to estimate a population, what indicators might they use instead?

Answer 18

size, density, dispersion, age structure

Question 19

Some organisms exhibit different dispersion patterns at different times of the year because

Answer 19

environmental conditions favor growth, germination, movement, and mating.

Question 20

Exponential growth

Answer 20

rapid growth of the population where resources are plentiful

Question 21

logistic growth

Answer 21

realistic/sustainable growth of population

Question 22

What do ecologists know to be true about K?

Answer 22

-it’s the maximum population size a particular environment can carry
-K varies over space and time with abundance of limiting resources (crowding/resource limitation)

Question 23

Delta=

Answer 23

change in time

Question 24

N=

Answer 24

population size

Question 25

t=

Answer 25

time interval

Question 26

R

Answer 26

B-D

Question 27

Per capita

Answer 27

contribution an average member of population makes to number of individuals added/subtracted from the population in time interval.

Question 28

r

Answer 28

per capita change in population size that occurs at each instant time

Question 29

Intrinsic rate of intrest

Answer 29

per capita rate at which an exponentially growing population increases in size at each instant time.
-J shaped curve

Question 30

Density independent population

Answer 30

BR and DR that doesn’t change with population density.
-negative feedback loop; disease, competition, toxic waste. Birth and death rates not affected by population density

Question 31

Density dependent population

Answer 31

Birth and death rates rise as population density increases.

Question 32

ZPG =

Answer 32

high BR - high DR / low BR- low DR

Question 33

Carrying capacity (K)

Answer 33

maximum population size that a particular environment can sustain. varies over space and time with abundance of resources. crowding and resource limitation has profound effects on population growth.

Question 34

Logistic growth model

Answer 34

per capita rate of population growth approaches 0 as the population size nears K.
-Shaped curve (sigmoid)
-assumes that populations adjust instantly and approaches K smoothly

Question 35

The study of population dynamics focuses on complex interactions that cause a variety in population size. What are examples of those interactions?

Answer 35

Abiotic and Biotic factors

Question 36

Life history

Answer 36

traits that affect an organism’s schedule of reproduction and survival
-when reproduction begins, how often, how many offspring

Question 37

Semel parity

Answer 37

reproduction in which an organism produces all of its offspring at once (big-bang reproduction)

Question 38

Iteroparity

Answer 38

repeated reproduction

Question 39

K -selection

Answer 39

selection for traits that are advantageous at high densities

Question 40

r-selection

Answer 40

said to maximize r, intrinsic rate of increase and enviroments below k.

Question 41

Metapopulations

Answer 41

A group of spatially separated populations of one species that interact through emigration and immigration.
-habitats can be suitable/ non suitable/ occupied/ non occupied. patches.

Question 42

Population dynamics

Answer 42

Population fluctuations from year to year or place to place. Bust and boom cycles.
1. food shortage
2. predator-prey interactions

Question 43

Demographic transition

Answer 43

High BR and DR to Low BR and DR. Associated with better health care and education.
Commonly graphed like pyramids
-K= 10 to 15 bil for humans

Question 44

Age structure

Answer 44

relative number of individuals at each age in population. illuminates social conditions.

Question 45

Ecological footprint

Answer 45

the aggregate land and water area required by each person, city, or nation, to produces all the resources it consumes and to absorb all the waste it generates. shows how close we are to K