7D Ecosystems

Question 1

What do the arrowns show in a food chain?

Answer 1

The arrows in a food chain show the direction of energy flow in the environment.

Question 2

Which direction do the arrows go in a food chain?

Answer 2

The arrows in a food chain go horizontally left to right,

Question 3

How do food webs differ from food chains?

Answer 3

Food webs differ from food chains by showing a more realistic model of feeding realtionships where animals have more than one food source.

(They are not only drawn left to right either!)

Question 4

Give some adaptations of a polar bear to explain how it survives in the arctic.

Answer 4

Choose from:

Thick fur to keep it warm,

white fur to camouflage it so it can hide and wait for seals to come up to breathe

wide paws to spread its weight over thin ice.

furry pads on its feet to prevent it from slipping on the ice.

sharp teeth to catch seals

large size (large surface are to volume ratio) to prevent heat loss

small tail and ears to prevent them getting cold.

long nose to awarm up air on the way into the lungs

Question 5

What is a habitat?

Answer 5

Where an organism lives/ it’s home.

Question 6

Which words describes an organism which is eaten by another?

Answer 6

Prey.

Question 7

What feeding level is a cow?

Answer 7

it is a primary consumer / a herbivore

Question 8

What is the name to describe an organism which makes its own energy?

Answer 8

Producer - Any organism which carries out photosynthesis eg plants, algae and cyano bacteria

Question 9

Where is energy stored in an organism?

Answer 9

In its muscles and fat.

Question 10

Name 2 physical factors which can effect the environment an organism lives in.

Answer 10

Light, temperature, soil type, wind speed, salinity.

Question 11

Why was the pesticide DDT banned?

Answer 11

DDTis a poison which persists in the environement for a long time. It was used to kill mosquitoes and prevent malaria which it did very well but sadly it also had side effects which devastated the populations of birds of prey.

The poison remains in the fat stores of animals and is passed on through the food chain. This is called BIOACCUMULATION.

Birds such as peregrine falcons had very high levels in their bodies and this prevented them from forming hard shells on their eggs. The eggs cracked in the nest under the birds and the chicks died.

DDT is now banned and the bird numbers are recovering.

Question 12

In a food chain, not all the energy is passed onto the next level.

What happens to it?

Answer 12

It is lost as

• movement,
• respiration,
• growth,
• reproduction &
• excretion,

Question 13

Why are there always fewer predators in a food chain than prey?

Answer 13

There always fewer predators in a food chain than prey because 90% of the energy is lost as it passes from one organism to another through the food chain.

Question 14

Plants need light to grow,

What other resources do they need?

Answer 14

Plants also need water and minerals.

Question 15

What word describes the animals moving to an another country to follow a food source?

Answer 15

Animals moving to an another country to follow a food source is called migration

Question 16

What is the name of an organism which eats a producer?

Answer 16

An organism which eats a producer is called a primary consumer.or herbivore

Question 17

How is this bird adapted to eat flesh?

Answer 17

A short, sharp and hooked beak can be used to tear flesh.

Question 18

What is the name for a predator at the top of the food chain?

Answer 18

A predator at the top of the food chain is called an apex or top predator.

Nothing elese will eat it.

e.g. bear, eagle, killer whale

Question 19

Why is a pyramid of biomass a better model of energy flow in the environment than a pyramid of number

Answer 19

A pyramid of biomass is a better model of energy flow in the environment than a pyramid of number because by weighing the organisms rather than counting how many of them there are you will ALWAYS get a pyramid with a wider base.

If you only have one tree and don’t take account of its mass to start the food pyramid it gives an unbalanced pyramid shape.

Question 20

What does trophic level mean?

Answer 20

The trophic level means the feeding level such as producer, primary consumer, secondary consumer etc.

Question 21

What do you call an animal which comes out mainly at night?

Answer 21

An animal which comes out mainly at night is said to be nocturnal.

Question 22

Why are some animals nocturnal?

Answer 22

So there are less animals around which might attack it.

Question 23

Why do some animals such as bears or dormice hibernate in winter?

Answer 23

Bears and dormic hibernate in winter so that they don’t starve as there is very little to eat in the forest in winter.

Question 24

Why do all food chains start with a producer?

Answer 24

All food chains start with a producer because only plants (and other organisms which photosynthesise) can lock up the energy of the sun that all living things rely on.

Question 25

Give an example of the way that humans can affect the environment to reduce biodiversity.

Answer 25

Humans can affect the environment to reduce biodiversity by

using poisons such as insecticides and herbicides,

destroying a habitat by buiding or mining so that species of plants, fungi or animals become isolated from the rest of their group.

overhunting animals so that they become extinct

polluting an environment with poisonous gases, poisonous metals or plastics

cutting down forests to grow food instead

outcompeting native herbivores by introducing cattle or sheep

intoducing new predators onto an island

burning fossil fuels to increase climate change

Question 26

What does biodiversity mean?

Answer 26

Biodiversity means the variety of life on Earth, in all its forms and all its interactions.