Ecosystems

Question 1

What is an ecosystem

Answer 1

All the abiotic and biotic components in a specific area and their interactions

Question 2

What are the components of an ecosystem and their definitions

Answer 2

Habitat - place where an organism or population live
Population - group of organisms of the same species, living in the same place that can interbreed
Community - all the populations of different species in a specific area that interact with each other

Question 3

What is a niche

Answer 3

An organisms role in the ecosystem

Question 4

What is a producer

Answer 4

An autotrophic organism that obtains food from inorganic sources via photosynthesis or chemosynthesis

Question 5

What is a consumer

Answer 5

Heterotrophic organism that obtains food in organic form

Question 6

What is a decomposer

Answer 6

Saprotrophs that feed on dead organic matter to release molecules, mineral and energy that then becomes available in that ecosystem

Question 7

Why is energy lost between trophic levles

Answer 7

Organisms die, egestion, some parts of organism not eaten, lost in respiration

Question 8

How to measure energy content of an organism

Answer 8

Dry the sample
Burn sample in a bomb calorimeter and heat water
Use specific heat capacity to find the amount of energy transferred to the water
this is the amount of energy that was stored

Question 9

What is productivity

Answer 9

The rate at which energy passes through each trophic level - it takes time into account

Question 10

What is NPP

Answer 10

Net primary productivity - rate at which plants convert light energy to chemical energy
Gross PP - Respiratory heat loss = NPP

Question 11

What environmental factors can be manipulated to improve NPP

Answer 11

Light, water, temperature, pests, nutrients

Question 12

What are saprotrophs

Answer 12

Organisms that feed by secreting enzymes onto food and absorbing digested enzymes across their outer walls

Question 13

What is the formula for efficiency

Answer 13

Biomass transferred / biomass intake * 100

Question 14

What is nitrogen fixing

Answer 14

Nitrogen is converted to ammonium ions
Fixed by Rhizobium bacteria in root nodules and azotobacter in the soil
Catalysed by nitrogenase

Question 15

How do plants and animals use fixed nitrogen

Answer 15

Use NH4+ to make amino acids and protein
In animals

Question 16

What is nitrification

Answer 16

The process in which ammonium compounds in the soil is converted into nitrogen containing compounds
Done by nitrifying bacteria

Question 17

How is the relationship between rhizobium and plants symbiotic

Answer 17

Plant gains amino acid from nitrogen fixing, bacteria gain carbohydrates made during photosynthesis

Question 18

What are the stages of nitrification

Answer 18

NH4 oxidised by nitrosomonas to NO2 -
NO2 - oxidised by nitrobacter to NO3 -

Question 19

What is denitrification

Answer 19

Denitrifying bacteria convert nitrate to N2 in anaerobic conditions (waterlogged soils)

Question 20

What is the carrying capacity

Answer 20

The max population size that can be supported sustainably in a particular habitat

Question 21

What is a limiting factor

Answer 21

The one factor affecting a process as it is nearest to its lowest value

Question 22

What are K-strategists

Answer 22

A species whose population size is determined by carrying capacity

Question 23

What are r-strategists

Answer 23

A species whose population size increases so quickly that it can exceed carrying capacity of the habitat before limiting factors have an effect

Question 24

What are the two types of competition

Answer 24

Intraspecific - within the same species
Interspecific - between different species

Question 25

What is competitive exclusion

Answer 25

The idea that two species with exactly the same niches cannot co-exist

Question 26

What is sustainability

Answer 26

The responsible management of resources - including environmental, economic and social dimensions

Question 27

What is rotational coppicing

Answer 27

When trees or shrubs are cut very close to the ground, leaving a short stool that wood grows out of Each year a different area is coppice till all of it is done

Question 28

What are the positive and negative aspects of coppicing

Answer 28

+ lets in light for other plants - inc biodiversity + Different parts of the woodland are at different stages - maxes biodiversity + Prevents succesion - Some species rely on larger trees for grazing and habitats

Question 29

What is Pollarding

Answer 29

Branches are cut off the tree higher to the trunk

Question 30

What is Clear Felling

Answer 30

Removal of all trees in an area at once

Question 31

What are the negatives of clear felling

Answer 31

Dec soil fertility Pollution from soil goes into water ways Destroys habitats

Question 32

What are techniques to increase timber production sustainability

Answer 32

Selective cutting Long rotation Coppicing

Question 33

How do you calculate population size of a species

Answer 33

Mean number of individuals in each quadrat/fraction of total area covered by each quadrat

Question 34

What is Primary succession

Answer 34

The succession that occurs on an area where no living beings are present by a pioneer species

Question 35

What do pioneer species do

Answer 35

First species to colonise bare ground, they are able to survive in difficult conditions Cause an inc in soil, soil fertility + nutrients, provide shelter, inc water holding capacity of soil

Question 36

What happens when a new area is uncovered

Answer 36

Primary succession - pioneer species They get displaced in the next seral stage Climax community develops

Question 37

What is a climax community

Answer 37

The final community in a succession

Question 38

What is deflected succession

Answer 38

When human activities prevent the climax community from being developed

Question 39

What are the key principles of ecotourism

Answer 39

Ensure tourism doesnt exploit the natural environment and local communities Consult and engage with local communities on planned developments Ensure that infrastructure improvements benefit locals and tourists

Question 40

What techniques are used to promote sustainable fishing

Answer 40

Use nets with different mesh sizes - allow immature fish to escape Only allow fishing at certain times of the year Fish farming

Question 41

What conditions are needed for nitrogen fixing

Answer 41

Supply of Hydrogen and ATP Anaerobic conditions