Ecosystems/populations/sustainability Module 6

Question 1

Habitat?

Answer 1

Place where an organism lives

Question 2

Population?

Answer 2

All the organisms of one species in a habitat

Question 3

Producer?

Answer 3

Organisms which produces organic molecules using sunlight energy

Question 4

Decomposer?

Answer 4

An organism that breaks down dead or undigested organic materials

Question 5

Trophic level?

Answer 5

A stage in a food chain occupied by a particular group of organisms

Question 6

Ecosystem?

Answer 6

All the organisms living in a certain area, and all the non-living conditions found there

Dynamic system

Question 7

Biotic factor?

Answer 7

Living features of an ecosystem

Question 8

Abiotic factor?

Answer 8

Non living features of an ecosystem

Question 9

How is energy transferred through an ecosystem?

Answer 9

Enters via photosynthesis
Plants store this as biomass
Energy passed on through organisms by eating each other

Question 10

Why is not all energy passed on to the next trophic level?

Answer 10

Some of energy is never taken in, in the first place:
. Plants can’t use all light energy that reaches their leaves initially as some is wrong wavelength, reflected or passes through
Or light hits part of leaf which can’t photosynthesise

Some parts of organism aren’t eaten eg. bones or roots

Some parts are indigestible, forming faeces

Lost via respiration

Question 11

Gross productivity?

Answer 11

The rest of the energy which is taken in (around 40%)

Question 12

Net productivity?

Answer 12

The amount of energy available for the next trophic level

Question 13

How do you find net productivity (biomass)?

Answer 13

gross productivity - respiratory loss

Question 14

What do herbicides do?

Answer 14

Kill weeds that compete with agricultural crops for energy

Question 15

What do fungicides do?

Answer 15

Kill fungal infections that kill crops

Question 16

What do insectides do?

Answer 16

kills insect pests

Question 17

What do fertilisers do?

Answer 17

chemicals that provide crops with minerals needed for growth eg. nitrates

Question 18

How are intensive rearing livestock conditions controlled?

Answer 18

Animals kept in warm indoor pens, where movement is restricted, so less energy used moving around and keeping warm

Animals given food which is higher in energy than normal food

Question 19

Describe the carbon cycle?

Answer 19

Carbon in form of CO2 in atmosphere is absorbed by plants when they carry out photosynthesis, becoming carbon compounds in plant tissues

Carbon passed on to animal consumers via feeding

All living organisms die and the Carbon compounds in the dead organisms are digested by micro organisms called decomposers, via saprobiontic feeding

Carbon returned to the air and water as all living organisms respire, including decomposers

However, if dead organic matter ends up in places where there aren’t any decomposers ( deep oceans or bogs), can be turned into fossil fuels ( heat and pressure over long time)

Carbon in fossil fuels released when they are burned = combustion

Other rocks formed from dead organic matter on sea floor, these rocks drawn down by tectonic plates, undergo chemical changes and release CO2, returned to atmosphere via volcanoes

Other rocks can also become land where they become chemically weathered and release CaCo3 ions into groundwater, which form the carbon containing rocks described above

Question 20

Describe the Nitrogen cycle?

Answer 20

Nitrogen fixation
Ammonification
Nitrification
Denitrification

Question 21

What’s Nitrogen fixation?

Answer 21

When Nitrogen gas in the atmosphere is turned into ammonia by bacteria such as Rhizobium and Azotobacter. The ammonia can then be used by plants

Also gets into system via lightening or fertilisers

Question 22

Where’s Rhizobium found and it’s relationship?

Answer 22

Found inside root nodules of leguminous plants

Mutulastic relationship with the plants, as they provide plants with Nitrogen compounds, and they provide them with carbohydrates

Question 23

Where do azobacter live?

Answer 23

Soil

Question 24

What’s ammonification

Answer 24

When nitrogen compounds from dead organisms are turned into ammonia by decomposers, which go on to form ammonium ions

Question 25

What’s nitrification?

Answer 25

When ammonium ions in the soil are changed into Nitrogen compounds which can then be used by plants (Nitrates)
First nitrifying bacteria Nitrosomanas changed ammonium ions into Nitrites
Then Nitobacter turns Nitrites into Nitrates

Question 26

What’s denitrification?

Answer 26

When Nitrates in the soil are converted into Nitrogen gas by denitrfying bacteria, as they use Nitrates in soil for respiration, under anaerobic conditions

Question 27

What’s succession?

Answer 27

Process in which an eco-system changes over time, biotic changes due to abiotic changes

Question 28

What’s primary succession?

Answer 28

When there’s no soil, just start with bare rock

Question 29

What’s secondary succession?

Answer 29

Happens on land which that’s been cleared off all the plants, but where all the soil remains eg forest fire

Question 30

Describe succession?

Answer 30

New species colonies land = the pioneer species

Abiotic condition are harsh as no soil, only specialised pioneer species can grow

Pioneer species changes abiotic conditions as they die decompose and form soil

Conditions less hostile and more organisms grow, more soil forms

Species become outcompeted as ecosystem becomes more complex and biomass increases

Reaches Climax community

Question 31

What’s the climax community?

Answer 31

An ecosystem which is supporting the largest and most complex community of plants and animals it can. It’s in a steady state

Question 32

What’s a plagioclimax?

Answer 32

When human activities prevent from reaching normal climax

Question 33

What’s deflected succession?

Answer 33

When succession prevented by human activity, but the plagioclimax formed is different to any of the normal stages

Question 34

What is population size affected by?

Answer 34

Abiotic factos

Biotic factors- interspecific competition, intraspecific competition, predation

Question 35

Describe interspecific competition?

Answer 35

Competition between different species

Reduced food sources
less food = less energy for growth and reproduction, both populations drop
Distribution affected, if ones better adapted other species will have to move

Think AC Milan vs INTER Milan

Question 36

Describe intraspecific competition?

Answer 36

When organisms of same species compete with each other for food resources

Question 37

Describe predation?

Answer 37

As prey pop increases, so does predators as there is more food, however more prey then eaten, so prey populations fall followed by predators

Question 38

Carrying capacity?

Answer 38

Maximum stable population of a species that an ecosystem can support

Question 39

Stages of population growth?

Answer 39

Lag phase
Log phase
Carrying capacity
Death phase

Question 40

What’s conservation?

Answer 40

Protection and management of ecosystems so natural resources can be used without them running out

Question 41

What’s reclamation?

Answer 41

Restoring ecosystems which have been damaged or destroyed

Question 42

Preservation?

Answer 42

The protection of eco-systems so that they’re kept exactly how they are

Question 43

How to manage woodland ecosystem in a sustainable way?

Answer 43

Trees cleared in small strips, grow back faster, and less soil erosion
Harvested via coppicing- cutting down trees in a way so can regrow, means don’t have to plant more
Plant only native tree species, aid ecosystem better
Planted trees attached to posts and glass tube, protecting them
Trees aren’t planted close together so don’t have to compete for resources

Question 44

Fishing quotas?

Answer 44

international agreements put limits on the amount of certain fish species allowed to be caught, thrown back in sea dead or dying, as can’t be brought back

Problems are fish of wrong species still caught,

Question 45

What does controlling mesh size of fishing nets do?

Answer 45

Reduces amount of unwanted fish caught accidentally, as bigger net size means will slip through
Also younger fish slip through net, allowing them to reach breeding age