Ecology - Competition & Interdependence, Biotic & Abiotic factors, Adaptations, Food chains

Question 1

Describe the levels of organisation in an ecosystem

Question 2

What is the habitat

Answer 2

The environment in which an organism lives

Question 3

What is a population

Answer 3

The total number of organisms of the same species living in the same geographical area

Question 4

What is an organism

Answer 4

An organism is a living thing

Question 5

Community

Answer 5

The populations of all the different species that live in the same habitat

Question 6

What is the biotic part of the environment

Answer 6

the community contains … All of the living organisms in an environment

Question 7

what does biotic mean

Answer 7

living

Question 8

What are the non-living parts of an environment called

Answer 8

The abiotic parts

Question 9

Examples of abiotic parts of the environment

Answer 9

Water
Minerals in the soil

Question 10

What is an ecosystem

Answer 10

Is both the biotic and the abiotic parts of an environment and how they interact

Question 11

What do organisms need in order to survive and reproduce

Answer 11

To survive and reproduce, organisms require a supply of materials from
their surroundings E.G. WATER and from the other living organisms there (e.g. animals can get materials from the plants that they eat)

Question 12

Why do living organisms compete

Answer 12

The resources that these organisms require in order to survive and reproduce are often in short supply, so this means that living organisms have to compete with each other

Question 13

What do plants compete for

Answer 13

Plants in a community or habitat often compete with each other for light and space, and for water and mineral ions from the soil.

Question 14

What do animals often compete for

Answer 14

Animals often compete with each other for food, mates (mating partners) and territory.

Question 15

What is interdependence

Answer 15

Within a community each species depends on other species for food (lions eat animals such as gazelles and zebras), shelter (tree shelters animals from the sun), pollination (plants depend on animals e.g. many plants depend on bees to spread their pollen..), seed dispersal (..or birds which can disperse speeds in their faeces) etc.
If one species is removed it can
affect the whole community. This is called interdependence

Question 16

Explain how If one species is removed it can
affect the whole community

Answer 16

E.g. without bees lots of different plants would not get pollinated, and would be unable to reproduce.
And animals which feed on these plants could then run out of food and their populations would fall.

Question 17

What is a stable community

Answer 17

A stable community is one where all the species and environmental factors (abiotic resources) are in
balance so that population sizes remain fairly constant.

Question 18

Describe biotic factors that can affect a community

Answer 18

availability of food (if the availability of food falls then the number of organisms in that community will also fall - all sources of food, plant or animal, are a biotic factor)

the arrival of a new predator (this can cause the population of a prey species to fall. A new predator can also affect existing predators e.g. if they are competing for the same prey., … lower availability of food, populations of existing predators will begin to fall)

• new pathogens (if an infectious disease emerges and then spreads, it can wipe out a population of a species)
• one species outcompeting another so the numbers are no longer sufficient to breed. (competition between species) - -if a species is outcompeted then its population can fall so much that the numbers are no longer sufficient to breed and the species may become extinct.

Question 19

Describe abiotic factors that can affect a community

Answer 19

light intensity (this can have a major effect on plants. All plants need light to carry out photosynthesis. However if the light intensity is too low, then the rate of photosynthesis falls and plants will grow more slowly - could cause decrease in population size of plants. If plants grow more slowly, then animals which feed on plants may not have enough food….. causing their populations to fall)

temperature (if the temperature of an environment changes then this could cause the distribution of species to change. E.g. animals could migrate and plant species might disappear from that area … could mean less food for organisms which depend on these animals or plants for food, causing populations to fall)

moisture levels (both plants and animals need water to survive so water is also a major abiotic factor)

soil pH and mineral content (important abiotic factor for plants. Many plants cannot grow on soil which is too acidic or too alkaline. Plants also need certain minerals in the soil e.g. nitrate which is used to make amino acids for proteins)

wind intensity and direction (can affect plants ..e.g. strong winds blowing inland from the sea can cause plants to lose water. So plants growing in sand dunes are often adapted to reduce water loss)

carbon dioxide levels for plants (CO2 is needed for plants to photosynthesise and if co2 levels fall then the rate of photosynthesis can also decrease)

oxygen levels for aquatic animals (o2 is needed for aerobic respiration. The level of oxygen in the air stays fairly constant. However the level of dissolved oxygen in water can fall for example on hot days. This can be harmful to aquatic organisms such as fish.

Question 20

What are biotic factors

Answer 20

The living parts of an environment

Question 21

What are the abiotic factors

Answer 21

The non-living parts of an environment

Question 22

Describe how organisms are adapted to living in their natural environment (structural, behaviour or functional adaptations)

Question 23

What is a structural adapatations

Answer 23

Structural adaptations are adaptations of body shape or body structure that allow an organism to live in an environment

Question 24

What is a functional adaptation

Answer 24

Functional adaptations are adaptations to the body functions of an organism

Question 25

What is a behavioural adaptation

Answer 25

Adaptations to the animal’s lifestyle or behaviour

Question 26

What is meant by an extremophile

Answer 26

Some organisms live in environments that are very extreme, such as
at high temperature, pressure, or salt concentration. These organisms
are called extremophiles

Question 27

Example of an extremophile

Answer 27

. Bacteria living in deep sea vents are
extremophiles

Question 28

Structural adaptations of a camel

Answer 28

Camels are adapted to the hot and dry conditions of a desert

Camels have a hump on their back which is a store of fat
Fat is a thermal insulator
By storing the fat in one place, this allows heat loss from the other parts of the camel’s body
This reduces water loss from sweating.

Metabolic reactions can be used to produce water from the fat

Camels have a thick coat on the upper surface of their body. This insulates the top of the camel from the heat of the sun. This reduces water loss from sweating

The inside of a camel’s mouth is leathery.
This means that they can chew desert plants which often have thorns
These plants can be a good source of water

Camels have long eyelashes to keep dust out of their eyes
They can also close their nostrils to keep dust out of their nose

Camels have wide feet which prevents the camel from sinking into the sand

Question 29

Functional adaptations of a camel

Answer 29

Produce concentrated urine and dry faeces. Both of these reduce water loss.

Camels can tolerate very large changes in their body temperature. This helps them to cope with the intense heat of the desert

Question 30

Behavioural adaptations of kangaroo rats

Answer 30

Kangaroo rats are nocturnal. They are mainly active at night. This means that they avoid the heat of the day time

During the day, kangaroo rats live in burrows underground
This keeps them cool and protects them from predators

Question 31

Structural adaptations of arctic fox

Answer 31

Arctic foxes are adapted to live in cold conditions

Arctic fox has very thick fur
This provides insulation and reduces heat loss to the air
The artic fox also has fur on the soles of the feet
This provides insulation and reduces heat loss to the ice and the snow

The artic fox has very small ears
This reduces the surface area (to volume ratio) of the fox, reducing heat loss

The arctic foxes coat provides effective camouflage which helps the Arctic fox to hunt its prey/to protect them from being eaten by predators

Question 32

Structural adaptations of cacti (plant)

Answer 32

Cacti are very well adapted to living in dry conditions

One big problem that plants face in dry conditions is losing water through their leaves - Cacti have solved this problem

Some cacti have very small leaves which reduces water loss
Other cacti have no leaves at all, only spine (this means that no water can be lost through their leaves)
These spines also protect the cactus from animals

Deserts are very dry and it does not rain very often
Because of this cacti have extensive and shallow roots
These allow cacti to catch as much water as possible after rainfall before the water evaporates or sinks into the ground

Cacti can also store water in their stem
This means that cacti can survive for many months without rain

Question 33

The antelope squirrel lives in hot deserts in parts of the USA and Mexico. It has grey fur and small ears and does not sweat. It has sharp claws which enable it to dig burrows, in which it lives. Above ground, during the hottest parts of the day it often holds its large tail over it head, or it lies in the shade with its limbs spread out wide

Give one functional adaptations the antelope squirrel has to its environment

Answer 33

It does not sweat

Question 34

The antelope squirrel lives in hot deserts in parts of the USA and Mexico. It has grey fur and small ears and does not sweat. It has sharp claws which enable it to dig burrows, in which it lives. Above ground, during the hottest parts of the day it often holds its large tail over it head, or it lies in the shade with its limbs spread out wide

Explain one behaviour adaptation the antelope squirrel has to its environment

Answer 34

it holds its tail over its head - so it can shelter from the heat of the sun s

it lies in the shade so it can shelter from the sun

it lies with its limbs spread out wide - so it can lose more heat (as its surface area to volume ratio is increased)

it lives in burrows, so it can avoid the heat above ground

Question 35

describe what is happening

tree -> caterpillar -> bird

Answer 35

We start with a tree and The leaves of the tree are being eaten by the caterpillar. the caterpillar is then eaten by the bird

Question 36

What is the producer in most food chains

Answer 36

This is usually a green plant or alga which makes glucose by photosynthesis.

Question 37

What do producers do.
Explain the importance of producers in food chains

Answer 37

They are the producers

This is because they synthesise complex molecules
(Green plants make the molecule glucose by photosynthesis
To do this they use energy from sunlight)

They are the source of all the biomass in a community/for the food chain

Question 38

What are photosynthetic organisms in relation to food chains

Answer 38

photosynthetic organisms are the
producers of biomass for life on Earth.

Question 39

What can molecules such as glucose be referred to as

Answer 39

Biomass

Question 40

What happens to the molecules like glucose - after they have been synthesised by the producers

Answer 40

These molecules now pass down the food chain to other organisms

Question 41

What are primary consumers

Answer 41

Organisms that eat the producers

Question 42

What are secondary consumers

Answer 42

Organisms/An animal that eats a primary consumers

Question 43

How many stages does this food chain have
Tree -> caterpillar -> robin -> hawk

Answer 43

This food chain has 4 stages

Question 44

What is a tertiary consumer

Answer 44

An animal/organism that eats a secondary consumer

Question 45

What is a predator

Answer 45

Consumers that kill and eat other animals

Question 46

What is a prey

Answer 46

The animal that is being eaten (by another animal/consumer)

Question 47

Describe how numbers of predator and prey rise and fall in cycles - with the example of rabbit (prey) and fox (predator)
It is a warm summer. Explain how this effects population of each species

Answer 47

The population of rabbits increases, as there is plenty of grass for the rabbits to eat.
This means more of the rabbits offspring survive so the rabbit population increases.

Now the foxes have more rabbits to kill and eat, so after some time, the fox population also increases

Because there are now more foxes, that means more rabbits will be eaten, so now the population of rabbits fall

Now the foxes have fewer rabbits to kill and eat, so after some time the population of foxes also falls

At this point, because the number of foxes has fallen, more rabbits will now survive and reproduce
So the population of rabbits now increases again

Question 48

the numbers of predator and prey rise and fall in cycles
when is this only true

Answer 48

This is only true in a stable community

Question 49

A caterpillar lives in the woods
Lately, a bird has been introduced to the woods
Explain how the introduction of the bird might cause the population sizes of both species to fluctuate over time

Answer 49

At first the population size of the caterpillar would decrease, as it would be eaten by the bird

This would lead to a decline in the population of the bird (as they have less caterpillars to eat),

allowing an increase in the population of the caterpillar.

The population of the bird would then increase as they have more caterpillars to eat

And the cycle would start again

Question 50

suggest why the predator-prey cycles are always out of phase with each other

Answer 50

The predator-prey cycles are always out of phase with each other
Because it takes time for one population to respond to changes in the other population
For example, when the number of rabbits goes up, the numbers of foxes doesn’t increase immediately, because it takes time for them to reproduce

Question 51

grass -> grasshopper -> rat -> snake
all the rats in the area are killed
explain two effects that this could have on the food chain

Answer 51

the population of grasshoppers could increase
as there is nothing to eat them
The population of snakes could decrease
as there is nothing for them to eat

Question 52

Food chain

Answer 52

Feeding relationships within a community can be represented by food chains

Question 53

Feeding relationships within a community can be represented by _______

Answer 53

Feeding relationships within a community can be represented by
food chains