B4.1 - Ecosystems

Question 1

Decomposers

Answer 1

An organism that decomposes dead organic matter

Question 2

Detritivores

Answer 2

A decomposer that eats and digests the dead organic matter to internally gain nutrients

Question 3

Examples of decomposers

Answer 3

Bacteria
Fungi
Protists

Question 4

Examples of detritavores

Answer 4

Earthworms
Millipedes
Sea stars

Question 5

How to decomposers break down the dead organic matter

Answer 5

Secretes enzymes that externally digest the dead organic matter

Question 6

Autotrophs

Answer 6

Make their own food

Question 7

Sacrotrophs

Answer 7

Feed on dead matter

Question 8

Petrotrophs

Answer 8

Eat lots of different things

Question 9

What is nitrogen needed for

Answer 9

Protein,

DNA

Question 10

Ecosystem definition

Answer 10

An ecosystem is made up of all living organisms and physical conditions within an area

Question 11

Community definition

Answer 11

All of the living organisms within an ecosystem

Question 12

Habitat

Answer 12

The area in which an animal/group of organisms live

Question 13

Population definition

Answer 13

The total number of individuals within ONE species

Question 14

Detritavores

Answer 14

They are very small animals break down larger decaying matter into smaller parts, preparing them for decomposers to then break down

Question 15

Biomass

Answer 15

The total dry mass of an organisms- (including bones)

Question 16

How can biomass be lost in a food chain

Answer 16

Respiration
Egestion
Excretion
When animals eat each other, they do not eat the entire animals. Things like BONES are left over, so not all biomass is transferred

Question 17

Ultimate source of energy for all organisms is

Answer 17

Sunlight - used for photosynthesis in producrs

Question 18

Difference between food web and food chain

Answer 18

Food chain is one small sequence but a food web is a group of interlinked food chains

Question 19

Biotic factors

Answer 19

All living things, e.g. animals or plants

Question 20

Abiotic factors

Answer 20

Non living things, the physical conditions. Such as light levels, temperature, pH, wind etc, even rainfall amounts

Question 21

Interspecific competition

Answer 21

BBETWEEN species

Question 22

Intraspeciifc competition

Answer 22

Within species

Question 23

What can organisms compete over

Answer 23

Habitat/territory
Food
Mates
Resources
Prey

Question 24

How does light intensity affect an ecosystem

Answer 24

Light is needed for photosynthesis - so the producers can make their energy and hence provide the rest of the food web with energy to survive.

On lower light, some plants have broader leaves to maximise the amount of light absorbed

Question 25

How does temperature affect and ecosystem

Answer 25

Temperature is important to control enzymatic reactions such as metabolic reactions. This is key in the growth of plants and animals

Question 26

How does water/moisture level affect an ecosystem

Answer 26

Lack of water leads to death Water is main part of blood plasma and hence needed by animals, but plants also need it for photosynthesis. Water also helps keep plant cells turgid

Question 27

How doe soil pH affect ecosystems

Answer 27

pH alters the availability of minerals in the soil, which plants need. Some plants grow better in different pH levels

Question 28

What can plants compete over

Answer 28

``` Light Water Carbon dioxide Space Minerals from soil ```

Question 29

Mutualism

Answer 29

When both organisms benefit - e.g. plants and animals

Question 30

Predation

Answer 30

The relationship between predator and prey

Question 31

Parasitism

Answer 31

When only one organism benefits | E.g. tapeworms in animal’s digestive system

Question 32

How is pyramid of biomass different to pyramid of numbers

Answer 32

Numbers can be inverted, since it depends on the organisms. Since, one whale has to eat thousands of krill. Inversely, several woodpeckers can feed off of one huge tree. Biomass pyramids are usually the normal shape, since biomass is always lost as u go up a food chain

Question 33

How do scientists calculate biomass

Answer 33

Take samples of organisms from each trophic level. Measure average mass of each organisms and multiply by the number of organisms to find total biomass at each trophic level Since it is DRY mass, organisms have to be killed and kiln dried to remove any wated

Question 34

3 things which get revcyecled in Nature

Answer 34

Nitrogen CO2 Water

Question 35

Example sod detritavores

Answer 35

Earthworm Woodlouse Maggot

Question 36

Factors affecting rate of decomposition/composting

Answer 36

Warm temperature - if too high, enzymes denature and no longer break down. At lower temps, the ROR is too low Moisture - low water causes reactions to slow and hence slows decomposition Aerobic conditions - the decomposers need oxygen to aerobically respire and get energy. They can’t survive in anaerobic conditions.