Topic 2.1 - 2.2

Question 1

What is an ecosystem?

Answer 1

A complex system including all living organisms and their environment.

Question 2

Why are ecosystems considered open systems?

Answer 2

They exchange energy and matter with their surroundings.

Question 3

What is the primary source of energy in ecosystems?

Answer 3

Sunlight.

Question 4

What process do producers use to convert sunlight into energy?

Answer 4

Photosynthesis.

Question 5

According to the law of conservation of energy, what happens to energy in an ecosystem?

Answer 5

It transforms but is not destroyed.

Question 6

How is energy lost in an ecosystem?

Answer 6

As heat during metabolic processes.

Question 7

What makes matter cycling in ecosystems different from energy flow?

Answer 7

Matter is recycled, while energy flows and is lost as heat.

Question 8

What key cycles are involved in matter recycling?

Answer 8

Carbon, nitrogen, and phosphorus cycles.

Question 9

How does human activity disrupt energy and matter flow in ecosystems?

Answer 9

Through pollution, deforestation, and climate change.

Question 10

What role does photosynthesis play in the carbon cycle?

Answer 10

It absorbs CO₂, helping regulate atmospheric carbon levels.

Question 11

What is the second law of thermodynamics in the context of ecosystems?

Answer 11

Energy transformations lead to degradation and heat loss.

Question 12

How much energy is typically transferred to the next trophic level?

Answer 12

About 10%.

Question 13

Why do energy pyramids have a pyramid shape?

Answer 13

Due to energy loss at each trophic level.

Question 14

What is primary productivity?

Answer 14

The rate at which producers create biomass from energy.

Question 15

Define gross productivity in an ecosystem.

Answer 15

Total energy captured by photosynthesis.

Question 16

What is net primary productivity (NPP)?

Answer 16

Biomass left after accounting for energy lost in respiration.

Question 17

What is trophic efficiency?

Answer 17

The percentage of energy passed to the next trophic level.

Question 18

How is ecological efficiency calculated?

Answer 18

(Energy at higher level / Energy at lower level) × 100.

Question 19

What are ecological pyramids?

Answer 19

Diagrams showing numbers, biomass, or energy across trophic levels.

Question 20

How do energy pyramids differ from biomass pyramids?

Answer 20

Energy pyramids always have a traditional pyramid shape due to energy loss.

Question 21

What is bioaccumulation?

Answer 21

Gradual buildup of pollutants in an organism over time.

Question 22

How does biomagnification affect predators?

Answer 22

Pollutants increase at each trophic level, impacting higher-level predators.

Question 23

What are microplastics, and why are they harmful?

Answer 23

Tiny plastic particles that persist in the environment, harming wildlife.

Question 24

Define maximum sustainable yield (MSY).

Answer 24

The largest sustainable harvest from a species’ stock.

Question 25

What practices help achieve MSY in forestry?

Answer 25

Sustainable logging and balanced harvesting.

Question 26

What is the biosphere?

Answer 26

Earth's system where life exists, comprising individuals, populations, communities, and ecosystems.

Question 27

What factors affect population size?

Answer 27

Natality, mortality, immigration, and emigration.

Question 28

What is an ecological niche?

Answer 28

The role and habitat requirements of a species in an ecosystem.

Question 29

Define intraspecific competition.

Answer 29

Competition between individuals of the same species.

Question 30

What is interspecific competition?

Answer 30

Competition between different species for the same resource.

Question 31

Describe parasitism.

Answer 31

A relationship where one organism benefits at the expense of another.

Question 32

What is mutualism?

Answer 32

A relationship where both species benefit.

Question 33

Explain the concept of carrying capacity.

Answer 33

Maximum population size an environment can sustain.

Question 34

What is a J-curve in population growth?

Answer 34

A growth pattern showing rapid growth followed by a sudden drop.

Question 35

Define an S-curve.

Answer 35

Population growth that stabilizes at carrying capacity.

Question 36

How do density-dependent factors regulate population size?

Answer 36

They limit growth as population density increases.

Question 37

Give an example of a density-independent factor.

Answer 37

Natural disasters like floods or fires.

Question 38

What is a keystone species?

Answer 38

A species that has a disproportionately large impact on its ecosystem.

Question 39

Describe the concept of r-strategists.

Answer 39

Species that reproduce quickly with many offspring, suited for unstable environments.

Question 40

What are K-strategists?

Answer 40

Species with fewer offspring, high parental care, suited for stable environments.

Question 41

What is a clade?

Answer 41

A group consisting of an ancestor and all its descendants.

Question 42

How does human technology affect carrying capacity?

Answer 42

Increases it by improving resource extraction and adaptability.

Question 43

What role do decomposers play in ecosystems?

Answer 43

Break down dead organic matter, recycling nutrients.

Question 44

Define density-dependent limiting factors.

Answer 44

Factors like predation and disease that impact populations based on density.

Question 45

What is an example of mutualism in nature?

Answer 45

Lichen, a partnership between fungus and algae.

Question 46

What are autotrophs?

Answer 46

Organisms that produce their own food from inorganic sources.

Question 47

What are heterotrophs?

Answer 47

Organisms that obtain food by consuming other organisms.

Question 48

How do chemoautotrophs obtain energy?

Answer 48

By oxidizing inorganic molecules like hydrogen sulfide.

Question 49

What is secondary productivity?

Answer 49

The rate consumers convert energy from food into their own biomass.

Question 50

What is Gross Secondary Productivity (GSP)?

Answer 50

Total biomass from food minus energy lost in feces.

Question 51

Define ecological efficiency in a food chain.

Answer 51

The ratio of energy passed from one trophic level to the next.

Question 52

What is a food web?

Answer 52

A network showing how energy and matter flow between organisms in an ecosystem.

Question 53

How does a pyramid of biomass differ in aquatic vs. terrestrial ecosystems?

Answer 53

Aquatic pyramids can be inverted due to fast turnover in primary producers.

Question 54

What is entropy in an ecological context?

Answer 54

A measure of disorder, increasing with energy transformations in ecosystems.

Question 55

What is a realized niche?

Answer 55

The actual conditions in which a species lives due to competition and other factors.

Question 56

What is the role of trophic levels in energy flow?

Answer 56

They represent stages in energy transfer within an ecosystem.

Question 57

Why is the law of conservation of energy essential in ecosystems?

Answer 57

It explains why energy is transformed but never created or destroyed.

Question 58

How does energy degradation impact higher trophic levels?

Answer 58

It results in less usable energy as energy moves up the food chain.

Question 59

What is net secondary productivity (NSP)?

Answer 59

Biomass remaining after accounting for respiration losses in consumers.

Question 60

Why are density-independent factors important for population dynamics?

Answer 60

They control population sizes regardless of density, such as climate events.