Ecosystems

Question 1

What is an ecosystem?

Answer 1

A distinct, self-supporting system of organisms which interact with each other and with the physical environment. They can be small or large.

Question 2

What is the definition of an abiotic factor?

Answer 2

A non-biological/ non-living part of an ecosystem.

Question 3

What is the definition of a biotic factor?

Answer 3

A living part of an ecosystem.

Question 4

What is an example of an abiotic factor?

Answer 4

Soil
Water
Air

Question 5

What is an example of a biotic factor?

Answer 5

Plants
Animals

Question 6

What is the definition of a habitat?

Answer 6

Where specific organisms live.

Question 7

What is the definition of the population in an ecosystem?

Answer 7

The number of a particular species in an ecosystem at a given time.

Question 8

What is the definition of the community in an ecosystem?

Answer 8

Populations of different species added together.

Question 9

What biotic factors may affect an ecosystem?

Answer 9

• Plant material as food
• Number of potential predators and prey

Question 10

What abiotic factors may affect an ecosystem?

Answer 10

• Purity of water/soil
• Weather/light intensity
• Amount of water - deep/shallow

Question 11

Why would it be impractical to count every organism in an ecosystem?

Answer 11

• There are too many
• Some may be re-counted or not counted at all
• May be difficult to tell apart different individuals.

Question 12

What are quadrats?

Answer 12

Metal frames placed on the ground, so organisms within can be counted.

Question 13

Why must sampling be random?

Answer 13

To avoid bias.

Question 14

How can sampling be random?

Answer 14

Using dice to determine the X, Y coordinates where you place your quadrat.

Question 15

How do you sample an area?

Answer 15

Using quadrats and percentage cover.

Question 16

How do you determine the total population of a particular species in an area?

Answer 16

You sample, and then add up your sampling area to calculate the total.

Question 17

What is biodiversity?

Answer 17

The variety of life on earth and the essential interdependence of all things.

Question 18

What is a main feature of a highly biodiverse ecosystem, and what is an example of one?

Answer 18

A large variety of different species, a coral reef.

Question 19

What do arrows in food chains show?

Answer 19

The flow of energy.

Question 20

Where does energy in a food chain come from?

Answer 20

The producer creates its own food, using energy it gained from the sun.

Question 21

How does a producer make its own energy?

Answer 21

Photosynthesis.

Question 22

What is a trophic level?

Answer 22

A level of feeding (trophic means feeding)

Question 23

What is a predator?

Answer 23

An animal which eats other animals.

Question 24

What is prey?

Answer 24

An animal which gets eaten by other animals.

Question 25

What does a decomposer do, and what is an example of one?

Answer 25

Consumes/ breaks down all organisms. Fungi or bacteria

Question 26

What are the different types of consumers?

Answer 26

- Primary Consumer - Secondary Consumer - Tertiary Consumer - Quaternary Consumer (Apex Predator)

Question 27

What does apex predator mean?

Answer 27

An animal that is a predator, but does not have any predators itself. (Top of the food chain)

Question 28

Why are food webs better than food chains? (On paper)

Answer 28

Food chains are oversimplified. Food webs show a collection of them, and show more interactions between organisms.

Question 29

Why are feeding relationship diagrams usually pyramid- shaped?

Answer 29

Energy is lost at each trophic level.

Question 30

How much energy is lost at each trophic level?

Answer 30

Approximately 90%

Question 31

Why do most food chains not have more than 5 trophic levels?

Answer 31

Too much energy is lost at each trophic level.

Question 32

Why is there a loss of energy at each trophic level (in animals)?

Answer 32

- Egestion (feces) - Excretion (carbon dioxide, sweat, urine) - Temperature (respiration) - Movement - Not all of the organism is eaten ( tail, bones, organs, roots (plants) )

Question 33

What two types of pyramids are there when depicting food chains?

Answer 33

- Pyramids of numbers - Pyramids of biomass

Question 34

What is biomass?

Answer 34

The dry mass (no water)

Question 35

How can you calculate an organism's dry mass?

Answer 35

Put it in the oven at 101 degrees celcuis, then keep weighing and re-weighing until it no longer loses any mass.

Question 36

How can you calculate a species' biomass?

Answer 36

Mass of living material x number of organisms.

Question 37

What are carbon atoms needed for in living organisms?

Answer 37

Making carbohydrates, proteins, lipids and DNA.

Question 38

How do plants and animals obtain their carbon?

Answer 38

Plants from carbon dioxide by photosynthesis, animals from plants by feeding.

Question 39

Which processes put carbon dioxide into the atmosphere?

Answer 39

Combustion Respiration

Question 40

Which processes take carbon dioxide from the atmosphere?

Answer 40

Photosynthesis Fossilisation

Question 41

What do nitrifying bacteria do?

Answer 41

Change ammonium into nitrites and then into nitrates.

Question 42

What do nitrogen fixing bacteria do in the root nodules?

Answer 42

Turn nitrogen gas into ammonium and then plant protein.

Question 43

What do denitrifying bacteria do?

Answer 43

Turn nitrates into nitrogen gas.

Question 44

What are nitrogen atoms needed for in living organisms?

Answer 44

Making DNA and proteins.

Question 45

How do plants and animals obtain their nitrogen?

Answer 45

Plants get it from nitrates in the soil by nitrification (and assimilation) and animals get it from plants by feeding.

Question 46

Which processes put nitrogen into the soil?

Answer 46

Lightning on nitrogen gas, nitrification, and nitrogen fixation.

Question 47

Which process takes nitrogen from the soil?

Answer 47

Denitrification

Question 48

What types of plants contain nitrogen-fixing bacteria in their root nodules?

Answer 48

Legumes

Question 49

How do the bacteria in the root nodules of legumes benefit?

Answer 49

They get glucose.

Question 50

How do the legumes with bacteria in their root nodules benefit?

Answer 50

They get ammonia, which can be converted into amino acids. (nitrification can occur)