Ecosystems

Question 1

Ecosystem

Answer 1

All the organisms and the environment in which they live form an ecosystem (it may be large, such as a rainforest or small, such as a pond)

Question 2

Community

Answer 2

All the organisms that live and interact in an ecosystem form a community.

Question 3

Population

Answer 3

The community is made up of populations of difference species. these species depend on each other for resources, so we say that they are INTERDEPENDENT

Question 4

Habitat

Answer 4

Each population lives in a particular habitat within the ecosystem, It includes the other organisms that affect the population and the local environment.

Question 5

Abundance

Answer 5

Is a measure of how common something is in an area, such as its population size. Measuring population size by counting all the organisms in an area is often impossible. However my you can estimate population size by taking samples using a quadrat.

Question 6

using a quadrat

Answer 6

Quadrats are placed randomly in the area and the number of individuals in each quadrat is counted.

Question 7

Estimating population size

Answer 7

Number of organisms in all quadrats x (total size of area where organism lives/total area of quadrats)

Question 8

Trophic levels

Answer 8

The feeding levels of a food chain.

Question 9

Biomass

Answer 9

The mass of tissues

Question 10

Energy transfer between trophic levels

Answer 10

Only 10% of energy gets transferred through each trophic. The rest of the energy is used for functions like respiration, excretion etc. (MRS NERG)

Question 11

Calculating efficiency of energy transfer

Answer 11

Energy transferred to biomass/total energy supplied to organism.

Question 12

Abiotic factors

Answer 12

Non living factors that affect the distribution of organisms

Question 13

Biotic factors

Answer 13

Living factors that affect the distribution of organisms

Question 14

Belt transect

Answer 14

The effect of abiotic factors on the distribution of organism can be measured using a belt transects and quadrats places along the transect.

Question 15

Pollutants

Answer 15

Substances that cause harm to the environment.

Question 16

Biodiversity

Answer 16

The number of species

Question 17

Lichen

Answer 17

Grows on trees and indicates that the air is polluted with sulfur-containing gases.

Question 18

Blackspot fungus

Answer 18

Pathogen of roses that cannot grow well when there is a lot of sulfur pollution.

Question 19

Sludge worm

Answer 19

Are present when water pollution levels are high.

Question 20

Parasitism

Answer 20

A different kind of feeing relationship in which only the parasite benefits, by feeding off a host organism, causing harm to the host

Question 21

Mutualism

Answer 21

When some organisms that live together both benefit from the relationship. These relationships are said to be mutualistic. (For example: many flowers depend on instincts for pollination . The flower depends on insects for pollination and the insect benefits by collecting nectar or pollen from the flower, which it uses for food).

Question 22

Fish farming

Answer 22

Fish farming aims to produce more fish and so reduce overfishing of wild fish

Question 23

Evaluation of fish farming

Answer 23

• causes problems because so many fish are kept in a relatively small space. Uneaten food and the faces from the fish skink to the bottom of the water. Therefore, parasites and disease spread more easily between fish in pens and they need to be treated to keep them healthy.
• Fish farming aims to produce more fish and reduces overfishing of wild fish.

Question 24

Eutrophication

Answer 24

• fertilizer is added
• heavy rain washes fertilizer off
• nitrates and phosphates dissolve in soil water
• nitrates and phosphates not taken up by the plants are washed into river
• high concentration of those nutrients encourages rapid growth of plants and algae
• surface plants block sunlight so plants in the water die and stop producing oxygen
• bacteria used to break down dead materials increase and use more oxygen
• the oxygen decreases rapidly
• aquatic animals die