3.7.4 Populations in Ecosystems Flashcards Preview

AQA A Level Biology > 3.7.4 Populations in Ecosystems > Flashcards

Flashcards in 3.7.4 Populations in Ecosystems Deck (13)
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1
Q

What is ecology?

A

The study of the inter-relationships between organisms and their environment, including abiotic and biotic factors

2
Q

What are the two major processes within an ecosysten?

A

The flow of energy

The cycling of elements

3
Q

What is the carrying capacity?

A

The size of the population that the ecosystem can support

4
Q

What affects the carrying capacity?

A

The effect of abiotic factors

Interactions between organisms e.g. competition and predation

5
Q

How is the growth of a population expressed?

A

Through logarithms

6
Q

What are the common abiotic factors?

A

Temperature
Light
PH
Water and humidity

7
Q

What is a stable population?

A

Where the birth rate and death rate are in balance and so there is no increase or decrease in the population size

8
Q

What is an increasing population?

A

Where there is a high birth rate, giving a wider base to the population pyramid and fewer old people, giving a narrower apex to the pyramid
This happens in economically less developed countries

9
Q

What is a decreasing population?

A

Where there is a lower birth rate (narrower base) and a lower mortality rate leading to more elderly people (wider apex)
Occurs in economically more developed countries

10
Q

What is intraspecific competition?

A

Competition which occurs between individuals of the same species
This occurs over food, water, breeding sites, etc

11
Q

What is interspecific competition?

A

Competition between individuals of different species for food, light, water, etc

12
Q

What is the rule about ecological niches?

A

Two species cannot occupy the same niche so the one that uses the resources most effectively will eliminate the other

13
Q

What is an ecological niche?

A

Where ar organism lives and what it does there

No two species occupy the same ecological niche

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