YEAR 9+10 - Topic 6 - Organisms and the environment

Question 1

Define this term:

Population

Answer 1

Population is the amount of a certain type of species there is in a certain area.

Question 2

Define this term:

Community

Answer 2

A community is all of the different species living in the same space.

Question 3

Define this term:

Habitat

Answer 3

Habitat is the place where an organism lives.

Question 4

Define this term:

Ecosystem

Answer 4

An ecosystem is all the organisms living in the habitat and the habitat.

Question 5

What is biodiversity?

Answer 5

Biodiversity is the variety of different species of organisms on earth or within an ecosystem.

Question 6

Why is biodiversity important?

Answer 6

Biodiversity makes sure that ecosystems are stable because different species depend on each other for things like food and shelter. Different species can also maintain the right physical environment (eg. Soil acidity).

Question 7

What is an abiotic factor?

Answer 7

An abiotic factor is non-living conditions that affect the distribution of an organism.

Question 8

What is a biotic factor?

Answer 8

A biotic factor is living organisms that affect other populations in an ecosystem.

Question 9

List Abiotic factors:

Answer 9

• oxygen levels (aquatic animals)
• CO2 levels
• light intensity
• moisture/ rainfall levels
• soil mineral content
• soil/ water pH
• temperature
• wind direction and intensity

Question 10

List biotic factors:

Answer 10

• availability of food
• new pathogens
• new predators
• one species out competing another

Question 11

What is a quadrat?

Answer 11

A quadrat is a square frame that encloses an area, normally 1m squared. It is used to collect and compare data about organisms in a habitat.

Question 12

How do you work out the population of an area using quadrats?
If a student used 0.5m 2 quadrats randomly across a 800m 2 field and had a mean of 10 daisies per quadrat, how any daisies are in the field?

Answer 12

1/0.5 = 2
2 X 10 = 20 daisies/m2
20 X 800 = 16,000 daisies in the field

Question 13

What is a belt transect?

Answer 13

A belt transect is a line of quadrats laid out along a line at regular intervals to compare data about distribution across a habitat.

Question 14

What is a food chain?

Answer 14

A food chain is a series of organisms that depend on the next as a source of food.

Question 15

Design an experiment for whether the height of the leaf on the tree affects the photosynthesis.

Answer 15

Change the height the leaf is picked from. Use the exact same tree and type of tree. Repeat the experiment 3 times and compare results to check your accuracy. Measure and compare the darkness of the leaves, using a colourimetre. Keep the tree, type of tree, place of the tree, 2 heights, time of day, season, amount of shade, CO2, light intensity, size of leaf the same.

Question 16

Where does energy originally come from?

Answer 16

The sun

Question 17

What is the first trophic level?

Answer 17

Producer - it produces its own food through photosynthesis.

Question 18

What is the second trophic level?

Answer 18

Primary consumer - this eats the producer, is a herbivore and is prey.

Question 19

What is the third trophic level?

Answer 19

Secondary consumer - consumes the primary consumer, is a carnivore and can be both prey and predator.

Question 20

What is the fourth trophic level?

Answer 20

Tertiary consumer - also known as apex consumer, it is a carnivore, eats the secondary consumer and is a predator.

Question 21

How much of the light energy is used by producers during photosynthesis?

Answer 21

1% because the other 99% is:

• reflected off the leaves
• not absorbed
• not all gets to the leaves
• may not be used due to limiting factors
• miss the chloroplasts
• converted into heat in photosynthesis/ respiration
• used as light energy to evaporate excess water from the leaves

Question 22

How much energy in organisms is passed on to the next trophic level?

Answer 22

10% because the other 90% is:

• not eaten (like bones)
• not digested and lost in excretion
• lost as heat energy in cellular respiration to carry put other life processes

Question 23

Why is the number of trophic levels in a food chain limited?

Answer 23

The number of levels in a food chain is limited because of the continual loss of energy. Less and less energy is available the higher up the food chain you go. More than 5 levels isn’t possible.

Question 24

Can energy be created or destroyed?

Answer 24

NO, it is must transformed into a different form.

Question 25

What happens to energy put into something?

Answer 25

It is either:
-transferred usefully
OR
-wasted

Question 26

How do you work out the total input energy?

Answer 26

Add together the useful and wasted energy.

Question 27

How do you work out energy efficiency?

Answer 27

% energy efficiency = energy becomes part of biomass
—————————————— X 100
Energy available

Question 28

What happens when prey population increases? (9 marks)

Answer 28

As prey population increases, it provides more food for predators, allowing them to survive and reproduce. This creates an increase in predators.
The larger predator population eats more prey organisms, causing a decrease in prey. The death rate of prey is higher than their survival rate.
The predator population decreases as there is not enough prey to feed all of them.
Reduced predator numbers means that there is less prey being killed, so they survive and reproduce more again. This process repeats itself.

Question 29

What is a biological pyramid?

Answer 29

A biological pyramid shows the population of each organism going up each trophic level. Not always a pyramid shape.

Question 30

What is a pyramid of biomass?

Answer 30

A pyramid of biomass shows the mass of each organism (in g/cm2) in each trophic level at a certain point in time. Always in a pyramid shape.

Question 31

Surface area and volume:

What would a large animal be?

Answer 31

A large animal would have a small surface area to volume ratio. This means they have less contact with the air/ground, so they wont lose much heat. (They will stay warm)

Question 32

Surface area and volume:

What would a small/ skinny animal be?

Answer 32

A small/skinny animal would have a larger surface area to volume ratio, so more in contact with the air/ground, meaning they would lose more heat. (This means that they would stay cooler)