How species depend on each other

Question 1

What is meant by the term ‘classification’?

Answer 1

Putting living things on Earth into groups based on similarities and differences

Question 2

What is a ‘species’?

Answer 2

A group of organisms that can breed together to produce fertile offspring

Question 3

Are horses and donkeys in the same species and why?

Answer 3

No, their offspring (mules) are infertile. This shows they are not in the same species

Question 4

What is meant by the term ‘adaptions’?

Answer 4

Features that help an organism survive in the habitat it lives in

Question 5

What is a ‘food web’?

Answer 5

A number of food chains conjoined

Question 6

What factors can cause a species to become extinct? [4]

Answer 6

[1] Rapid change in environment, eg climate
[2] New diseases
[3] New predators
[4] New competitors

Question 7

Why did the species known as the quagga become extinct?

Answer 7

Because of direct human activity

Question 8

Why did dodos become extinct?

Answer 8

Because they were flightless birds that couldn’t fight against other competitors for resources

Question 9

What is photosynthesis?

Answer 9

The process in which plants soak up sunlight do drive food production

Question 10

In a food chain what percentage of energy is passed onto the next level?

Answer 10

Around 10%

Question 11

How is energy passed out of a food chain? [4]

Answer 11

[1] Via heat energy
[2] Used for life processes
[3] Uneaten parts that pass to decomposers
[4] Is excreted and passed to decomposers

Question 12

What are the four stages of a food chain?

Answer 12

Producers
Primary consumers
Secondary consumers
Tertiary consumers

Question 13

What do we do if we want the percentage efficiency of energy transfer between producers and primary consumers?

Answer 13

[1] Calculate the total energy that came into the level of the food chain, eg:
4,500kJ + 500kJ = 5,000kJ
[2] Identify how much energy is transferred to the next level:
500kJ
[3] Calculate the efficiency of this transfer using the equation:
(Energy transferred to next level ÷ Total energy in) X 100
(500kJ ÷ 5,000kJ) X 100 = 10%
Answer = 10%

Question 14

CARBON CYCLE

1. How is carbon removed from the atmosphere?

Answer 14

Photosynthesis

Question 15

CARBON CYCLE

2. How is carbon returned to the atmosphere?

Answer 15

Through respiration

Question 16

CARBON CYCLE

3.How is carbon passed from one organism to the next?

Answer 16

Carbon from the plants eaten becomes part of the fats and proteins within the animal. Microorganisms and some animals feed on waste material from animals, and dead remains of animals and plants, meaning that the carbon has now become a part of them

Question 17

Why do plants and animals need nitrogen?

Answer 17

To make proteins

Question 18

What is ‘nitrogen fixation’?

Answer 18

Making nitrogen compounds from nitrogen in the air

Question 19

How are nitrogen compounds in living things returned to the soil? [2]

Answer 19

[1] Excretion of animals

[2] The decay of dead plants and animals

Question 20

Why can plants and animals not get nitrogen directly from the air?

Answer 20

Because it is fairly unreactive