B3 - Ecosystems And Interactions Between Organisms

Question 1

List the four different levels of ecosystem organisation.

Answer 1

Individual
population
Community
Ecosystem.

Question 2

What is a habitat?

Answer 2

A place where an organism live e.g a rocky shore or a field

Question 3

What is a species?

Answer 3

A group of similar organism that can reproduce with each other to give fertile offspring.

Question 4

In ecosystem, explain the individual level of organisation?

Answer 4

A single organism

Question 5

In ecosystem, explain the population level of organisation.

Answer 5

All the organisms of one species in a habitat

Question 6

In ecosystem, explain the community level of organisation.

Answer 6

All the organisms (different species) living in a habitat

Question 7

In ecosystem, explain the ecosystem level of organisation.

Answer 7

A community of organisations along with all the non-living (abiotic) conditions

Question 8

Organism need things from their environment and other organism in order to survive and reproduce. List the things a plant needs. (6)

Answer 8

Light 
Space 
Water 
Minerals from soil
Seed dispersers 
Pollinators

Question 9

Organism need things from their environment and other organism in order to survive and reproduce. List an animal needs. (5)

Answer 9

Space (territory)
Shelter 
Food 
Water
Mates

Question 10

What is the size of a population limited by?

Answer 10

Competition for resorted and predation

Question 11

Why is the population of red squirrels decreasing?

Answer 11

Competition with grey squirrels for resources in some areas mean that there isn’t enough food for red squirrels

Question 12

Who do organism compete with for resources?

Answer 12

Other species and member of other species.

Question 13

Name the two types of factors that cause change in the environment.

Answer 13

Abiotic (non-living)

Biotic (living)

Question 14

How can changes in the environment affect communities in different ways? (3)

Answer 14

Some species population size may increase, for others it may decrease or the distribution of population may change.

Question 15

List abiotic environment conditions that effect communities. (4)

Answer 15

Temperature
pH
Moisture level
Light intensity

Question 16

What is bioaccumulation?

Answer 16

At each stage of the food chain concentration of toxins increases, so organisms at the top of the food chain receive a toxic dose.

Question 17

How can expensive fertilises affect lakes and ponds

Answer 17

Excessive fertilisers cause increased growth of algae. The algae blocks the sunlight from plants which die. Microorganisms feeding of the dead plants use up the O2 in the water leading to the death of other organism e.g fish

Question 18

What is eutrophication?

Answer 18

The release of excessive fertilisers in to ponds and lakes causing increase growth of algae

Question 19

List biotic environment conditions that effect communities. (4)

Answer 19

Availability of food
Number of predators
Presents of pathogens
Presents of competitors

Question 20

How does the availability of affect communities? (Black birds)

Answer 20

E.g. in a Bumper year for berries, the population of black bird might increase because there will be enough food for all of them so they are more likely to survive and reproduce.

Question 21

How does the number of predators effect communities? (Lions)

Answer 21

E.g. if the number of lions (predator) decreases then the number of gazelles (pray) might increase because fewer of them would be eaten

Question 22

How does the presents of pathogens effect communities?

Answer 22

If a new pathogen is introduced into the community then population may decrease due to illness.

Question 23

How does the present of competitors affect communities?

Answer 23

Competition for food, water and space

Question 24

Give two abiotic factors that could effect the community in an ecosystem. (2 marks)

Answer 24

pH level
Temperature 
Moisture level
Light intensity 
Toxic chemicals
(One mark per listed effect)