Topic 5A: Factors Affecting Distribution And Abundance

Question 1

Define ecosystem

Answer 1

All the organisms living in a particular area and all the nonliving abiotic factors and how they interact

Question 2

Define habitat

Answer 2

The place where an organism lives for example a rocky shore a field

Question 3

Define population (biology)

Answer 3

All the organisms of one species in a habitat

Question 4

Define population size

Answer 4

The number of individuals of one species in a particular area

Question 5

Define community

Answer 5

All of the organisms of different species that live in the same habitat and interact with each other

Question 6

Define abiotic factors

Answer 6

The non-living features of an ecosystem e.g. temperature and moisture

Question 7

Define biotic factors

Answer 7

The living features of the ecosystem for e.g. the presence of predators or food

Question 8

Define abundance

Answer 8

The number of individuals of one species in a particular area

(Another word for population size)

Question 9

Define distribution

Answer 9

Where are species is within a particular area

Question 10

What is interspecific competition?

Answer 10

Different species compete with each other for same resources e.g. Food

Question 11

What is intraspecific competition?

Answer 11

Same species compete with each other for same resources

Question 12

How can population size vary due to favourable abiotic factors? Give examples (2)

Answer 12

Organisms grow fast and reproduce successfully when abiotic conditions are ideal(1)
living in ideal temperatures for metabolic reactions means that mammals don’t have to use as much energy maintaining body temperature therefore energy used for growth and reproduction(1)

Question 13

How can population size vary due to unfavourable abiotic factors? Give examples (2)

Answer 13

Organisms can’t grow as fast or reproduce as successfully (1)
E.g. When surrounding temperature is lower or higher than optimum body temperature, more energy used to maintain right body temperature, therefore less energy for growth and reproduction(1)

Question 14

What is carrying capacity?

Answer 14

The maximum stable population size of a species that an ecosystem can support

Question 15

Describe the process of intraspecific competition within species (4)

Answer 15

Population of the species increases when resources are plentiful. As population increases more organisms compete for same amount of space and food. (1)

Eventually resources become limiting(1)

Smaller population means less competition for resources that for better for growth and reproduction-population grows again (1)

Population size which is carrying capacity(1)

Question 16

Define predation

Answer 16

When an organism (the property) kills and it’s another organism (the prey)

Question 17

Describe how predator and prey population sizes are linked (3)

Answer 17

As prey population increases, there is more food for predators, so predator population grows(1)

As predator population increases more prey is eaten so pray population falls (1)

Therefore less food for Predators so population decreases and so on (1)

Question 18

Define niche (3)

Answer 18

The role of a species within a habitat and how it exploits it(1)

This includes biotic interactions and abiotic interactions (1)

A niche can only be occupied by one species (1)

Question 19

Explain how having a similar niche affect the abundance of two species in an area (3)

Answer 19

To species occupying similar niche is will compete(1)

For example food source(1)

So few individuals of both species will be able to survive in the area(1)

Question 20

Explain distribution using niche concept(2)

Answer 20

Organisms can only exist in habitats where all the conditions that make up the role exist(1)

For example soprano pipistrelle bat feeds on insects and lives in farmland open woodland etc - it couldn’t exist in a desert.(1)