Ecology

Question 1

What is population size?

Answer 1

The total number of individuals in a population

Question 2

How can the population size change?

Answer 2

It can increase, decrease or remain the same over time

It should generally go up

Question 3

What factors affect population size?

Answer 3

• Natality
• Mortality
• Immigration
• Emmigration

Question 4

What factors increase population size?

Answer 4

Natality

Immigration

Question 5

What factors decrease population size?

Answer 5

Mortality

Emmigration

Question 6

Show + population growth

Answer 6

(Natality + Immigration)>(Mortality + Emmigration)

Question 7

Show - population growth

Answer 7

(Natality + Immigration)

Question 8

Show no population growth

Answer 8

(Natality + Immigration)=(Mortality + Emmigration)

Question 9

What does it mean when resources in an area are scarce?

Answer 9

There is a limited population that can be supported

Question 10

What is carrying capacity?

Answer 10

The carrying capacity of an area is the total number of individuals that can be supported

Question 11

Populations tend to grow until what? What happens if the population continues to grow after that?

Answer 11

Until the carrying capacity is reached. If the capacity is exceeded, the population will decrease.

Question 12

What are the important characteristics of biological circles?

Answer 12

• Frequency of reproduction, age of sexual maturity

Question 13

What are the important characteristics of biological circles?

Answer 13

• Frequency of reproduction
• Age of sexual maturity
• Reproductive maturity
• Number of offspring

Question 14

Characteristics of biological circles vary by what?

Answer 14

They vary by species

Question 15

Usually, larger organisms have more or less offspring?

Answer 15

Less

Question 16

Usually, smaller organisms have more or less offspring?

Answer 16

More

Question 17

What types of factors influence populations? (Abiotic or Biotic)

Answer 17

Both

Question 18

Describe biotic factors. Give examples.

Answer 18

Living factors that can have an impact on a population

• Food
• Humans
• Bacteria
• Predation

Question 19

Describe abiotic factors. Give examples.

Answer 19

Non-living ecological factors of physical or chemical nature that can affect a population

• Sun light
• Atmospheric composition
• pH
• Temperature
• Pheromones

Question 20

Define limiting factors (population growth)

Answer 20

Factors that limit the number and growth of a population

Question 21

Give examples of biotic limiting factors

Answer 21

• Humans
• Predation
• Limited resources
• Parasites
• Bacteria
• Food

Question 22

Give examples of abiotic limiting factors

Answer 22

• Storms
• Droughts
• Floods
• Volcanic activity
• Deforestation
• Temperature
• Pheromones

Question 23

Name the different ways to estimate the size of a population

Answer 23

• Count
• Sample area
• Mark and recapture

Question 24

Describe how to estimate population size using sample area

Answer 24

1. Divide an area of land into equal plots and count the number of individuals in each plot
2. Calculate the average number of individuals in the plots by choosing 3 plots
3. Use proportion

Average # of individuals Total population
___________________= ______________
Area per plot Total area

Question 25

Describe how to estimate population size using mark and recapture

Answer 25

1. Capture/Trap an animal
2. Mark them with a tag, microchip or paint
3. When the already marked individuals are recaptured use proportion:

number marked (1st)   Number of recaptured with mark
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_=\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
size of whole population      Total caught in 2nd sample

Question 26

Why is mark and recapture used?

Answer 26

In the case that species move around a lot (migratory birds)

Question 27

A scientist captures 50 snakes and marks them. During recapture, 75 snakes are captures and 20 are marked. What is the total population?

Answer 27

187 snakes

Question 28

During mark and recapture, if you recapture less moarked of the species then will you have a higher or lower population?

Answer 28

Higher

Question 29

What is population density/how do you find population density?

Answer 29

The number of individuals of a species divided by surface area or volume of water.

Question 30

What is the formula for population density?

Answer 30

PD= number of individuals
_______________________
Space (mL, L, cm) occupied

Question 31

Calculate population density of the fleas:

2400 fleas on an elephant with a total surface area of 100m2.

Answer 31

24 fleas/m2

Question 32

What is population distribution?

Answer 32

Population distribution refers to the way in which individuals are spread out over a territory

Question 33

What are the different types of population distribution?

Answer 33

• Random
• Uniform
• Clumped

Question 34

Describe clumped popualtion distribution.

Answer 34

The most common distribution in nature.

Individuals form clusters that improve chance of survival when you are also a prey for a predator

Question 35

Describe uniform population distribution.

Answer 35

Individuals maintain an equal-ish distance from each other; this indicates strong competition for space and resources

Question 36

Describe random population distribution.

Answer 36

It occurs when there are the same conditions over a territory and little competion between individuals. (or when the conditions are just random)

This is more likely for plants than animals