Ecosystems

Question 1

What is an ecosystem?

Answer 1

A community of organisms (species) interacting in a given environment. This includes abiotic and biotic factors of the habitat.

Question 2

Give examples of micro-habitats

Answer 2

(small)

• tree stump
• aquarium

Question 3

Give examples of macro-habitats

Answer 3

(large)

• caribbean oceans
• african planes

Question 4

Name the characteristics of living things

Answer 4

• They are made out of cells
• They acquire and use energy (nutrients)
• They grow and develop (mitosis)
• They reproduce
• They respond and adopt to their environment (within reason)

Question 5

What are tropic relationsships often represented by?

Answer 5

A food chain

Question 6

How many trophic levels are there?

Answer 6

3

Question 7

What are the tropic levels?

Answer 7

Producers
Consumers
Decomposers

Question 8

Food chains are the representation of what?

Answer 8

The tropic relationships between different living things

Question 9

What are food webs?

Answer 9

A group of interrelated food chains

Question 10

In food webs/chains, aroows point to what

Answer 10

The direction of energy flow (things point to what they get eaten by)

Question 11

What is transformed/transferred in a food chain? What is this called?

Answer 11

Matter and energy

Energy flow

Question 12

All of the organic matter in an ecosystem is known as what?

Answer 12

Biomass

Question 13

What is biomass?

Answer 13

All of the organic matter in an ecosystem

Question 14

Flow of matter and energy can be represented by what?

Answer 14

Ecological pyramids, food webs and food chains

Question 15

Describe how ecological pyramids represent the flow of matter and energy

Answer 15

Each trophic level is represented by a rectangle whose size is proportional to the amount of biomass it has

Question 16

Biomass represents what? Unit?

Answer 16

The total number of mass living in an ecosystem at any given time (kg)

Question 17

What happens to the amount of energy and biomass as it goes up a trophic level? Why?

Answer 17

Both energy and biomass usually decrease by a factor of 10 with each trophic level since organisms give off energy to breathe, eat, reproduce, move, etc.

Question 18

Trophic levels affect what? Why?

Answer 18

Relative abundance and population size for the whole ecosystem to remain in balance

Question 19

How much energy is transferred when going up a trophic level in a pyramid? How much is wasted?

Answer 19

10% transferred

90% wasted

Question 20

Is a rainforest or tundra more productive? Why?

Answer 20

Rainforest

Its biome supports more abundance and diversity

Question 21

Describe producers.

Answer 21

• They are autotrophs, so they produce their own food
• They convert inorganic material (H20, CO2) into organic material (protein, sugar)
• A principal mechanism includes the production of sugar by photosyntesis
  6CO2 + 6H2O + energy -> C6H1206 + 6O2

Question 22

Give examples of producers

Answer 22

• Algae
• Plants
• Cyanobacteria (blue-green algae): They were the first unicellular organism to produce O2 in Earth’s history

Question 23

What is primary productivity?

Answer 23

The total quantity of new organic material made by the producers in an ecosystem over a certain period

Question 24

Primary productivity depends on what factors (examples)

Answer 24

• Sun light
• Carbon dioxide concentration
• Availability of nutrients
• Water
• Temperature

Question 25

Plants and algae produce the most O2 at what temperature?

Answer 25

20 - 25C

Question 26

Primary productivity is highest in what areas? Why?

Answer 26

Costa Rica/Borneo

Because they are warm and humid

Question 27

Describe consumers

Answer 27

• They are heterotrophs because they get their food from a variety of other living things
  1. Primary consumers (herbivores): feed on leaves and fruit or their seeds
  2. Secondary and tertiary consumers (carnivores): feed on animals on the level below them (tertiary is highest, then secondary, then primary)
  Omnivores: consumers of multiple orders (levels) at once

Question 28

Describe decomposers

Answer 28

• They feed on dead and/or remains of producers and consumers
• This connects them to all the trophic levels

Question 29

Describe chemical recycling

Answer 29

• Occurs when decomposers make inorganic matter available in an ecosystem by breaking down organic matter
• At each tropic level in a food chain a certain amount of material is recycled by decomposers back into nutrients that producers can use

Question 30

Ecosystem dynamics respect what?

Answer 30

The law of conservation of energy

nothing can be created or destroyed, matter can only be transformed

Question 31

Who invented the law of conservation of mass?

Answer 31

Anotoine Laurent de Lavoisier

Question 32

What is an ecological disturbance?

Answer 32

An event that destroys/harms an ecosystem. It can lead to the elimination of organisms (extinction) and change the availability of resources

Question 33

Name and describe the types of disturbances

Answer 33

• Natural disturbances: occur due to environmental phenomena such as mud slides/floods
• Human disturbances: the main form of ecological disturbance on Earth

Question 34

What is ecological succession?

Answer 34

The series of changes that occur over time in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored

Question 35

How long does it take for a forest to regrow after a fire which destroys it?

Answer 35

150+ years

Question 36

What are ecological footprints?

Answer 36

The estimate of how much available resources we consume and how much waste we generate

Question 37

How is ecological footprint calculated?

Answer 37

Ecological footprint = Land + water occupied
+ land and water used to produce goods & services for a population
+ land and water used to dispose of our waste

Question 38

What does HPI stand for?

Answer 38

Happy Planet Index

Question 39

How is HPI calculated?

Answer 39

HPI= Experienced well-being x life expectancy
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Ecological footprint