Populations

Question 1

Define the term population

Answer 1

All the organisms/ populations present in an habitat

Question 2

Define the term community

Answer 2

All the organisms/ populations present in an habitat

Question 3

Define the term ecosystem

Answer 3

the community and the non-living / abiotic components of the environment

Question 4

Define the term niche

Answer 4

the role of the organism in its ecosystem

Question 5

What are abiotic factors?

Answer 5

non living factors

Question 6

What are biotic factors?

Answer 6

factors due to interactions of organisms, ie living factors

Question 7

Give examples of abiotic factors

Answer 7

• soil type
• ph
• CO2 concentration
• temperature
• light intensity
• water availability

Question 8

Give examples of biotic factors

Answer 8

• food availability
• predatation
• parasitism
• disease
• competition

Question 9

What do plants compete for ?

Answer 9

light, water, minerals

Question 10

What do animals compete for?

Answer 10

food, territory, mates, breeding sites

Question 11

What are the two types of competition?

Answer 11

-interspecific competition

intraspecific competition

Question 12

Define the term interspecific competition and give an example

Answer 12

competition between different species, eg. weeds and crop plants in a field competing for light and minerals

Question 13

Give an example of an organisms niche

Answer 13

• feeding role
• abiotic conditions it lives in
• its philosophy
• behaviour
• reproduction method

Question 14

Describe the relationship between the similarity of an organisms niche and the competition

Answer 14

the more similar the niches of two competitors, the greater the competition will be

Question 15

Define the term intraspecific competition and give an example

Answer 15

this occurs between individuals of the same species for the same resource , eg, to sow seeds at increasing densities otherwise in identical pots

Question 16

What actions can a farmer take to reduce the effect of intraspecific competition?

Answer 16

irrigate

add fertiliser to field, prevents mineral availability becoming a limiting factor

Question 17

Describe a predator

Answer 17

an organism that hunts, kills and eats another, the prey .

Question 18

What affect does a decline in prey numbers have on the predators?.

In response what will happen to the size of the prey population?

Answer 18

less food results in more intraspecific competition,
less reproduction,
increased morality so predator population decreases

fewer eaten,
more survive to breed,
so population inceases

Question 19

Define the term carrying capacity

Answer 19

the maximum size that a population can remain sustainable in a particular habitat

Question 20

What causes change in population size?

Answer 20

• the effect of abiotic factors

- interactions between organisms

Question 21

What are autotrophs?

Answer 21

primary producers

Question 22

What are heterotrophs?

Answer 22

`-primary consumers

• secondary consumers
• tertiary consumers

Question 23

Give an example of a decomposer

Answer 23

barteria and fungi

Question 24

What is a food chain ?

Answer 24

a series of trophic levels

Question 25

A food chain usually has 4 or 5 trophic levels but rarely 6. why do u think this is so?

Answer 25

energy is lost at each trophic level therefore there is not enough energy at the end of the food chain to support further trophic levels