Ecology

Question 1

Define species

Answer 1

A group of organisms that can interbreed and produce fertile offspring.

Question 2

Define population

Answer 2

A group of organisms of the same species who live in the same area at the same time.

Question 3

Define community

Answer 3

A group of populations living and interacting with each other in an area.

Question 4

Define ecosystem

Answer 4

A biological community of interacting organisms and their abiotic environment.

Question 5

Define ecology

Answer 5

the study of relationships between living organisms and between organisms and their environment.

Question 6

Define trophic level

Answer 6

The position of an organism in a food chain.

Question 7

Define interdependence

Answer 7

How different organisms in an ecosystem interact and are dependent upon each other .

Question 8

Define food chain

Answer 8

A simple diagram to track the flow of energy within an ecosystem.

Question 9

Define food web

Answer 9

A set of related food chains with connections to track the interconnectedness of the organisms in the ecosystem.

Question 10

Define a producer

Answer 10

Organisms that make their own food from their non living environment using photosynthesis.

Question 11

Define a consumer

Answer 11

Organisms that eat producers or their products, or eat each other.

Question 12

What is a population?

Answer 12

A group of organisms that interbreed and live in the same place at the same time

Question 13

What is a community

Answer 13

All the living organisms in an ecosystem

Question 14

What are species?

Answer 14

A species is a group of organisms that are able to interbreed and produce fertile offspring

Question 15

Name the species that are able to make their own food from inorganic materials.

Answer 15

Autotrophs

Question 16

What is the name of consumers that feed on living organisms by ingestion i.e. they obtain their food from organic matter e.g. Herbivores, carnivores.

Answer 16

Heterotrophs

Question 17

Name two types of heterotrophs

Answer 17

Detritivores

Saprotrophs

Question 18

Outline the characteristics of detritivores

Answer 18

Organisms that ingest dead organic matter such as fallen leaves or the bodies of dead animals e.g. earthworms, woodlice and millipedes

Question 19

Outline the characteristics of a saprotroph

Answer 19

Saprotrophs secrete digestive enzymes onto organic matter and then absorb their nutrients in a digested form e.g. bacteria and fungi. (egestion).

Saprotrophs are therefore responsible for the decomposition of organic matter and are often referred to as decomposers – they are crucial to the recycling of inorganic nutrients such as nitrogen compounds.

Question 20

What does the chi-squared test measure?

Answer 20

A mathematical way in which you can determine if the data you have observed is due to chance – by comparing it to the data you would have expected to produce.

Question 21

Define biomass

Answer 21

The total mass of a group of organisms. It consists of the cells and tissues of those organisms, including carbohydrates and other carbon compounds they contain. Carbon compounds have chemical energy so therefore biomass has energy.

Question 22

Outline how energy in food chains can be lost.

Answer 22

Not consumed – All parts of an organism may not be consumed and the parts that are not consumed still have energy stored

Not assimilated or lost through death – Not all parts of what is consumed is digested and absorbed so some passes out in the faeces.

Also if an organism dies and is not eaten by a predator but instead decayed by detritivores and saprotrophs then the energy in its body is lost to this food chain instead.

Cell respiration – Organisms need energy for cell activities and this energy (ATP) comes from cell respiration.

The only energy available to organisms in the next trophic level is chemical energy in carbon compounds that have not been used up in cell respiration or lost as heat.

Question 23

Explain how energy enters, flows through and is lost from marine food chains.

Answer 23

Light energy is converted to chemical energy (in carbon compounds/sugars) by photosynthesis.

Chemical energy in carbon compounds flows by means of feeding through food chains and webs.

Only approximately 10% of energy is passed to the next trophic level.

Energy is released as heat by respiration.

After death, energy may remain trapped as undigested detritus/fossil.

Question 24

Explain the transformation of carbon compounds in the carbon cycle.

Answer 24

Autotrophs convert carbon dioxide into carbon compounds eg. glucose in photosynthesis.

Carbon dioxide diffuses from the atmosphere into autotrophs.

Decomposers release carbon dioxide during decay/putrefaction.

Peat forms when organic matter is not fully decomposed because of acid/anaerobic conditions in waterlogged soils.

Question 25

Oxygen and nitrogen are not greenhouse gases because they do not absorb longer-wavelength radiation. True or false?

Answer 25

True

Question 26

Discuss the relationship between atmospheric carbon dioxide concentration and global temperature.

Answer 26

The greenhouse effect keeps the Earth warm.

Changes in human activity have led to increase in carbon dioxide concentration.

Carbon dioxide absorbs infrared/ long wave radiation + trapping heat.

Deforestation removes carbon sinks.