Populations In Ecosystems

Question 1

Niche

Answer 1

The role of a species within its habitat

Question 2

Abiotic

Answer 2

The non-living features of the ecosystem

Question 3

Biotic

Answer 3

The living features of the ecosystem

Question 4

Ecosystem

Answer 4

A community with all the abiotic conditions in the area in which it lives

Question 5

The niche a species occupies within its habitat includes:

Answer 5

It’s biotic interactions - what it eats etc

It’s abiotic interactions - the oxygen ur breaths in etc

Question 6

What happens if two species try to occupy the same niche?

Answer 6

They will compete with eachother - one species will be more successful than the other so only one of the species is left.

Question 7

What are adaptations?

Answer 7

Features that increase an organism’s chance of survival and reproduction.

Question 8

Adaptations can be:

Answer 8

Physiological

Behavioural

Anatomical

Question 9

Organisms with better adaptations are more likely to…

Answer 9

Survive, reprice and pass on their alleles for their adaptations - adaptations become more common - natural selection.

Question 10

Give 2 examples of adaptations to Abiotic conditions:

Answer 10

• seals have a thick layer or fat to keep them warm.

- hedgehogs hibernate to lower their rate of metabolism over winter.

Question 11

Give 2 examples of adaptations to Biotic conditions:

Answer 11

• some bacteria produce antibiotics to kill other species of bacteria.
• Male frogs have mating calls to attract females.

Question 12

What is the population size?

Answer 12

The total number of organisms of one species in a habitat.

Question 13

What is the carrying capacity?

Answer 13

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

Question 14

What happens when abiotic conditions aren’t ideal for a species?

Answer 14

The organisms can’t grow as fast or reproduce as successfully.

Question 15

What is Interspecific competition?

Answer 15

When organisms of different species compete with eachother for the same resources.

Question 16

What does interspecific competition do to the amount of resources?

Answer 16

Limits them to both the populations - so both populations will be limited and decrease in size.

Question 17

What happens if two species are competing but one is better adapted to its surroundings?

Answer 17

The less well adapted species is likely to be out-competed.

Question 18

What is Intraspecific competition?

Answer 18

When organisms of the same species compete with eachother for the same resources.

Question 19

What happens in Intraspecific competition?

Answer 19

• population of a species increases when resources are plentiful - as the population grows, more competition.
• these resources become limited so population begins to decline.
• smaller population means less competition so population grows again.

Question 20

Predation is where…

Answer 20

An organism kills and eats another organism.

Question 21

Describe a predator-prey cycle:

Answer 21

• the prey increases, more food so predators increase.
• predator increases, less prey as more is eaten so prey decreases.
• less food for predators so their population decreases and so on.

Question 22

What is Succession?

Answer 22

Succession is the process by which an ecosystem changes over time. The biotic conditions change as the abiotic conditions change.

Question 23

What is primary succession?

Answer 23

This happens on land that’s been newly formed or exposed e.g. where a volcano has erupted to form a new rock surface - no soil or organic material.

Question 24

What is secondary succession?

Answer 24

This happens on land that’s been cleared of all the plants but where the soil remains e.g. forest where trees have been cut down.

Question 25

Primary succession starts when…

Answer 25

A new species colonised a new land surface - this species is known as the pioneer species.

Question 26

What happens once the pioneer species has came?

Answer 26

• abiotic conditions are harsh so the pioneer species is adapted to it, once they die they change the abiotic conditions - forming a basic soil after they are decomposed.
• conditions are less hostile meaning new organisms with diff adaptations can form - they die and soil becomes deeper and richer so larger plants can grow.
• this means it becomes less suitable for previous species.

Question 27

Secondary succession happens when…

Answer 27

There is already a soil layer - but the pioneer species are larger plants.

Diff plants and animals that are better adapted for the improved conditions move in and out compete animals and plans already there - become dominant.

• as it goes in, ecosystem becomes more complex and biodiversity increases.

Question 28

What is the final stage of succession?

Answer 28

Climax community - when the ecosystem is supporting the largest and most complex community of plants and animals it can - it won’t change much as its already steady.

Question 29

Different species have different…

Answer 29

Climax communities - e.g. some species need a temperate climate while others need a polar climate.

Question 30

Describe the Mark-Release-Capture:

Answer 30

• capture a sample of species (counted)
• mark them in a harmless way.
• release back into habitat and wait for them to integrate again.
• take a second sample and count how many are marked.

Question 31

Describe how you would use Quadrats:

Answer 31

• use a random number generator to get a set of co-ordinates for two diff areas.
• place quadrats in those places and count how many species are in them.

-