Habitats and Ecosystems

Question 1

What does habitat mean?

Answer 1

A place where an organism lives.

Question 2

What does population mean?

Answer 2

All the organisms of the same species living in a habitat.

Question 3

What does community mean?

Answer 3

The populations of different species living in a habitat.

Question 4

What does abiotic factors mean?

Answer 4

Factors that affect a habitat that aren’t living.

Question 5

What does biotic factors mean?

Answer 5

Factors that affect a habitat that are living.

Question 6

What does ecosystem mean?

Answer 6

The interaction between a community of living organisms and their environment.

Question 7

Why do the organisms in an ecosystem interact with each other?

Answer 7

There is competition for food, light, mates, mineral ions, etc.

Question 8

What is interdependence?

Answer 8

When an organism relies on another, e.g. pollination and seed dispersal.

Question 9

What does it mean for an ecosystem if it is biodiverse?

Answer 9

It has many species and means the community and ecosystem is stable and populations don’t fluctuate.

Question 10

What is the benefit of a stable ecosystem?

Answer 10

It is more resistant to human activity and environmental change.

Question 11

How do we represent feeding relationships within a community?

Answer 11

Using a food chain, each part of the food chain is called a trophic level.

Question 12

What is trophic level one?

Answer 12

A producer (usually green plants or algae) makes glucose via photosynthesis.

Question 13

What is trophic level two?

Answer 13

Herbivores which eat plants and algae, primary consumer.

Question 14

What is trophic level three?

Answer 14

Carnivores which eat herbivores, secondary consumers.

Question 15

What is trophic level four?

Answer 15

Carnivores which eat other carnivores, tertiary consumers.

Question 16

What is a predator?

Answer 16

Animals that eat other animals.

Question 17

What is a prey?

Answer 17

Animals that get eaten by other animals.

Question 18

What is an apex predator?

Answer 18

A predator that has no other predators.

Question 19

What happens to the level of predators and prey in a healthy stable community?

Answer 19

It follows a cycle of negative feedback.

Question 20

What is a ‘predator-prey cycle’?

Answer 20

The prey population increases due to more food and less predators. The predator population begins to increase as there is more food. There is a delay however as it takes time for the predators to catch prey and then begin reproducing.

Because the predator population has increased more prey are hunted causing the prey population to decrease.

After a time predator population decreases as there is fewer prey to hunt and therefore more competition.

The cycle repeats.

Question 21

What is biomass?

Answer 21

Biomass is the mass of living material.

Question 22

How do we represent biomass in a food chain?

Answer 22

Pyramids are used to represent relative amount of biomass in each level of the food chain, the producers are always at the bottom.

Question 23

What is important to remember about biomass pyramids?

Answer 23

Label each trophic level and label the x axis with units.

Question 24

What happens to biomass through a food chain?

Answer 24

Biomass is lost at each trophic level, approximately 10% of biomass is passed up into the next trophic level.

Question 25

Why is biomass lost?

Answer 25

-Not all of the organism is edible or is eaten by other animals.
-Some absorbed material is egested as faeces.
-Some absorbed material is lost as waste e.g. carbon dioxide and water from respiration and urea.
-Used for respiration.

Question 26

How do we equate biomass lost?

Answer 26

Biomass in previous trophic level - Biomass in current trophic level

Question 27

How do we equate efficiency of transfer?

Answer 27

(Biomass in higher trophic level/Biomass in lower trophic level) * 100

Question 28

What is a transect?

Answer 28

A method of sampling used to measure the distribution of a species over a distance / across or along a habitat.

Question 29

Why do we do transects?

Answer 29

To evaluate whether an environmental factor may be affecting the distribution of a species along the transect.

Question 30

What different environmental factors can be measured when taking a transect?

Answer 30

-Light Intensity using a light meter
-Soil pH using an indicator
-Temperature using a thermometer
-Width of leaves using a ruler

Question 31

How do we carry out a transect?

Answer 31

1- Layout a tape measure across a desired area
2- Place a quadrat down continuously along the tape measure or at every other metre
3- Count and identify the species in the quadrat (use a key)
4- Use a meter to measure an abiotic factor at the same time if investigating how that factor affects species distribution (always measure at same height/direction)
5- Then repeat by completing another transect further along the habitat.
6- Repeat at different times of the day/season/year