Chapter 5

Question 1

Define population

Answer 1

A group of individuals belonging to the same species living in a particular area at the same time

Question 2

Why is it important for scientists to know the size of a population?

Answer 2

To understand the habitats and needs of organisms. This enables humans to sustain and ensure that vulnerable species persist and contribute to the planets biodiversity

Question 3

Define r selection

Answer 3

species quickly colinising an unstable ecosystem, leading to a pattern of rapid population increase and decrease and eventual take over by competitors

Question 4

what is a r-selected species

Answer 4

A fast growing and reproducing organism, often the first to occupy unused resources and living space

Question 5

What are the characteristics of an r selected species

Answer 5

Smaller size, short life cycles and a lack of parental care in young

Question 6

What are some examples of an r selected species

Answer 6

Mice, rats, frogs, toads, weeds and oysters

Question 7

Define k selection

Answer 7

While some individuals may not survive initially, over the long term a sustainable population can be maintained

Question 8

What is k selected species

Answer 8

A slow growing, long lived species typical of those in a climax community

Question 9

What are the characteristics of a k selected species

Answer 9

Live longer, breed later, have fewer offspring and devote their lives to ensuring the survival of offspring

Question 10

Examples of a k selected species

Answer 10

birds, larger mammals and larger plants.

Question 11

Define carrying capacity

Answer 11

The maximum population size of a species that can be supported in a given environment

Question 12

What is the equation for population growth rate?

Answer 12

Population growth rate = (Birth rate + Immigration rate) - (death rate + emigration rate)

Question 13

Explain the equation that calculates population growth rate

Answer 13

A population is increasing if the birth/immigration rate exceeds the death/emigration rate. Therefore, a population decreases when the death/emigration rate exceeds birth/immigration rate

Question 14

What is an open ecosystem

Answer 14

Where migration between populations of animals can occur but will affect the overall numbers in the ecosystem involved

Question 15

What is a closed ecosystem

Answer 15

Where migration doesn’t impact population size at all

Question 16

What is random distribution and an example

Answer 16

When organisms are spaced irregularly, the location of an organism does not affect the location of another. EG. Specific tree species in a forest.

Question 17

what is uniform distribution

Answer 17

Organisms are evenly spaced, the presence of one organism determines how close another will be. Common in high density populations like Penguins

Question 18

What is clumped distribution

Answer 18

A number of individuals are grouped together which make up the population as a whole

Question 19

Why is knowing the distribution of a species important

Answer 19

Knowledge of particular plant species can give glues about the distribution and abundance of animals that depend on them

Question 20

Disadvantages and advantages of direct observation

Answer 20

• Time consuming, dangerous

+ Satellites can be used in inaccessible regions

Question 21

What is direct observation

Answer 21

A method used to measure abundance. Eg, recording sightings at particular intervals

Question 22

What is a quadrat and the advantages and disadvantages

Answer 22

Where a square is placed on the ground to count each individual of a species. Useful for stationary organisms and faster. Needs to have appropriate number of quadrats, wont be accurate

Question 23

Population size equation

Answer 23

Total number of individuals counted / area of each quadrat x number of quadrats

Question 24

What is a transect and their advantages and disadvantages

Answer 24

Where a line is drawn through a community to determine the distribution of species. Get a good picture of the landscape over a distance. Can’t be used in marine ecosystems and if a large sampling interval is used, wont be accurate

Question 25

What is the capture mark recapture method and their advantages and disadvantages

Answer 25

When individuals are captured, marked and released and after time are recaptured to indicate population size. Easier than sampling every single member of the population Time, costly, species die, needs large sample size

Question 26

Equation for capture mark recapture

Answer 26

Total population = Number marked in first sample (M) x Number of animals recaptured (n) divided by number of recaptured animals that are marked (m)

Question 27

Advantages and disadvantages of telemetry

Answer 27

Shows pattern and behavior of animals | Time consuming and costly

Question 28

What is species distribution modeling

Answer 28

An attempt to predict future needs and resource management using computer technology

Question 29

What is an example of the carrying capacity theory

Answer 29

100 km^2 of eucalyptus forest is the minimum area possible to support 10 000 sugar gliders as a viable population. This info acts as a guide to the minimum size a park or any closed ecosystem needs to be to conserve animals. The area needs to be sufficient for a significant number of top carnivores to survive

Question 30

What is environment resistance

Answer 30

Happens when populations exceed carrying capacity. Leads to competition, disease, parasites, increase in predation, decrease in food supply

Question 31

What are density dependent factors

Answer 31

The greater the density of a population, the more individuals die or fail to reproduce. Eg. Competition, disease, parasites, predation, food supply

Question 32

What are density independent factors

Answer 32

Those that affect all individuals in a population regardless of age or stage. Eg, severe weather, volcanic activity, habitat destruction

Question 33

When is controlling populations needed

Answer 33

When one species increases at the expense of others. Can be controlled chemically or biologically

Question 34

What is chemical control

Answer 34

The chemical pesticides used to control pest species. Quick and effective but can be ecologically damaging and costly

Question 35

What is biological control

Answer 35

When living organisms are used to control pest species

Question 36

What are the four types of biological control

Answer 36

1. General predators - Organisms that consume a great variety of pest species. Eg, ladybirds target aphids, caterpillars, mites and beetles 2. Specialized predators - Organisms that target one pest species. Eg, dragonflies and mosquitoes 3. Parasites - organisms that lay their eggs in the bodies of hosts. Eg, wasps, flies 4. Microbial diseases - caused by bacteria, fungi and viruses that target species and cause death through illness

Question 37

Example of unsuccessful biological control

Answer 37

Cane toads were introduced to north east Queensland to control cane sugar beetle pests. Cane toads have rapidly expanded north and south of the original site

Question 38

Successful biological control

Answer 38

Wasps are being used to control the native stem-girdler moths that can decimate crops in Queensland. The wasps lay their eggs in the moth eggs, which are then consume by the wasp larvae

Question 39

Pest

Answer 39

Any species causes harm or death to other organisms