Populations

Question 0

Distribution

Answer 0

Geographical extent; may refer, for example, to a family, genus, species, or a particular population of a species.

Question 1

Define: population

Answer 1

All of the individuals of a species that live together in one place at one time.

Question 2

Demography

Answer 2

The statistical study of populations. It is used to predict how the size of a population will change.

Question 3

Sustainable

Answer 3

Able to be maintained, may describe an ecosystem in which the organism can reproduce and their offspring become established and grow, thus the biological community continues over time, even with a level of disturbance.

Question 4

Key features of populations

Answer 4

Population size
Population density
Dispersion

Question 5

Population size

Answer 5

Is the number of individuals in a population.
Has an important effect on the ability of the population to survive.
A small population is more likely to become extinct.

Question 6

A small population is more likely to become extinct when…

Answer 6

In the case of random events or natural disaster.
Due to inbreeding where the population is more genetically alike and recessive traits are more likely to appear.
With reduced variability it is harder to adapt to changes.

Question 7

Population density

Answer 7

The number of individuals in a given area.

If they are too far apart they may only rarely encounter one another resulting in little reproduction.

Question 8

Dispersion

Answer 8

The way in which the individuals are arranged.

Question 9

Population size is limited by…

Answer 9

Density-dependent factors and density-independent factors

Question 10

Density-dependent factors include…

Answer 10

Disease
Competition
Predators
Parasites
Food
Crowding

The greater the population, the greater effect these factors have. Eg: Black Death in the Middle Ages- more deaths in cities.

Question 11

Density-independent factors include…

Answer 11

Most are abiotic factors
Volcanic eruptions
Temperature
Storms
Floods 
Drought
Chemical pesticides
Major habitat disruption

Question 12

Predicting population growth

Answer 12

Nearly all populations grow exponentially as long as there are resources available.

Question 13

What are two of the most basic factors that affect the rate of population growth?

Answer 13

Birth rate and death rate

Question 14

r(rate of growth)= ?

Answer 14

r(rate of growth)= birth rate- death rate

Question 15

The exponential growth curve shows…

Answer 15

The population growth plotted against time.

Question 16

What does exponential growth show?

Answer 16

That as a population gets larger, it also grows at a faster rate.
This is the maximum population growth under ideal circumstances.
Includes plenty of room for each member, unlimited resources (food, water) and no hindrances (predators).

Question 17

Logistic model

Answer 17

This model accounts for the declining resources available to populations as they grow.
It assumes the birth and death rates are not constant.
As the population grows, births decline and death rises.
Eventually birth= death, so the population stops growing.

Question 18

What is the carrying capacity (K)?

Answer 18

The number of organisms of one species that an environment can support indefinitely.

Question 19

When does the exponential curve occur?

Answer 19

When there is no limit to population size.

Question 20

What does the logistic curve show?

Answer 20

The effect of a limiting factor.

Question 21

Population growth strategies include?

Answer 21

r-strategists

K-strategists

Question 22

Two ways a population can prosper are?

Answer 22

Depends on the rate of growth (r).

Influenced by the carrying capacity (K).

Question 23

r-strategists

Answer 23

r= rate of growth
Characterised by exponential growth, which results in temporarily large populations, followed by sudden crashes in population size. Eg: insects, bacteria, some plants.
Live in unpredictable and rapidly changing environments.
Reproduce quickly when conditions are favourable.
Many offspring: small, mature rapidly, no parental care.

Question 24

K-strategists

Answer 24

Characterised by a high degree of specialisation. Eg: trees, whales, tigers, etc.
Live in stable and predictable environments.
Can compete effectively.
Reproduce late in life.
Few offspring: large, mature slowly, often much parental care.
K= carrying capacity

Question 25

Human populations consist of…?

Answer 25

K-strategist characteristics.
In recent times however humans have learned to expand the carrying capacity of the environment bye increasing food supply, combating pests and curing diseases.

Question 26

Can the earth support this increase of humans?

Answer 26

Damage to the plant will eventually reduce the carrying capacity for humanity and slow the growth of the human population.

Question 27

What is competition?

Answer 27

The struggle between organisms for an environmental resource that is in limited supply.

Question 29

What is intra-specific competition?

Answer 29

Struggle between organisms of the same species for the same resources that are in limited supply.

Question 30

What is inter-specific competition?

Answer 30

Struggle between organisms of different species for the same resources that are in limited supply.