Chapter 14: Population Ecology

Question 1

Ecology

Answer 1

The study of the interactions between organisms and their environments

Question 2

Individuals

Answer 2

Individual organisms

Question 3

Populations

Answer 3

Groups of individual organisms that interbreed with each other

Question 4

Communities

Answer 4

Populations of different species that interact with each other within a location

Question 5

Ecosystems

Answer 5

All living organisms as well as non living elements that interact in a particular area

Question 6

Population Ecology

Answer 6

A sub field of ecology that focuses on populations of organisms of a species and how they interact with the environment

Question 7

Growth Rate

Answer 7

The change in the number of individuals in the population in some unit of time

Question 8

Calculating Growth Rate

Answer 8

The growth of the population in a year is the growth rate times the number of individuals present to start with

Question 9

r

Answer 9

Birth rate minus the death rate

Question 10

N

Answer 10

Number of individuals in the population now

Question 11

Exponential Growth

Answer 11

The bigger the population the faster it grows

Question 12

As population increases

Answer 12

Food supplies are reduced, less places to live, increased disease, and increased predation risk

Question 13

Population Density

Answer 13

The number of individuals in a given area

Question 14

Density Dependent Factors

Answer 14

Any factor limiting the size of a population whose effect is dependent on the number of individuals in the population. Ex. Disease

Question 15

Carrying Capacity

Answer 15

The ceiling of growth. Death rate increases, emigration rate increases, and usually a reduction in birth rate, reduction in fertility

Question 16

Slowing Down Exponential Population Growth

Answer 16

(r x N) x [(K - N)/K].

Question 17

Logistic Growth

Answer 17

When a population grows exponentially at first but then slows down as the population size approaches the carrying capacity

Question 18

Density Independent Factors

Answer 18

Forces like floods, earthquakes, and fires that disrupt growth. Takes time before Growth goes back to logistic Growth

Question 19

Maximum Sustainable Yield

Answer 19

The size of a natural population at which it produces a maximum rate of increase, usually about half of the carrying capacity

Question 20

Life History

Answer 20

Tells us as much about a species as possible in a small amount of information. Includes vital statistics, age at first reproduction, litter size, frequency, and longevity

Question 21

Reproductive Investment

Answer 21

All of the material and energetic contribution that an individual will make to its offspring

Question 22

Big Bang Reproduction

Answer 22

Reaches sexual maturity at one year, mates intensely over a 3 week period, males die shortly after mating period, and females usually die after weaning their first litter

Question 23

Fast, Intensive Reproductive Investment

Answer 23

Reaches sexual maturity at one month and produces litters of six to ten offspring every month

Question 24

Slow, Gradual Reproductive Investment

Answer 24

Reaches sexual maturity at one year and produces about one offspring per year

Question 25

What is the cost of the reproductive Investment during any reproductive episode?

Answer 25

Chance of predation and the wear and tear of reproduction on an individuals body takes its toll. Smaller litters are usually preferred because of the possibility of additional litters

Question 26

What is an individuals likelihood of surviving to have future reproductive episodes?

Answer 26

Small organisms like mice need to produce multiple offspring per litter while humans only need to produce one offspring per litter

Question 27

Tradeoffs: Reproduction and Survival

Answer 27

In Big Bang reproducers investment in reproduction is high. If individuals are physically prevented from reproducing they can live many more years

Question 28

Tradeoffs: Reproduction and Growth

Answer 28

Growth can sometimes be stunted when organisms spend time reproducing

Question 29

Tradeoffs: Number and Size of Offspring

Answer 29

Some lizards can lay more eggs if they are smaller but a higher proportion of the offspring survive if the eggs are larger

Question 30

Life Table

Answer 30

Tallies the number of people in a population within a certain age and the number of individuals within that age range that die

Question 31

Survivorship Curves

Answer 31

Graphs showing the proportion of individuals of a particular age that are now alive in a population

Question 32

Type I Survivorship Curve

Answer 32

High survivorship until old age, then rapidly decreasing survivorship

Question 33

Type II Survivorship Curve

Answer 33

Survivorship decreases at a steady pace

Question 34

Type III Survivorship Curve

Answer 34

High mortality early in life but those that survive the early years live long lives

Question 35

Aging

Answer 35

Emerges as a definitive and measurable feature. It is an increased risk of dying with increasing age after reaching the age of maturity

Question 36

Hazard Factor

Answer 36

Includes the risk of death from all types of external forces

Question 37

Demographic Transition

Answer 37

Refers to the transition from high birth and death rates to lower birth and death rates as a country develops into an industrialized economic system