Ecology

Question 1

What is an ecosystem?

Answer 1

A group of organisms interacting with each other and their physical environment for survival.

Question 2

What are biotic and abiotic factors?

Answer 2

Biotic factors: Living components (e.g., animals, plants, bacteria).

Abiotic factors: Non-living components (e.g., sunlight, water, rocks).

Question 3

Define a producer.

Answer 3

An organism (usually a plant) that makes its own food through photosynthesis.

Question 4

What is a consumer, and what are the three types?

Answer 4

A consumer eats other organisms for food. Types:

Herbivore: Eats plants only.
Carnivore: Eats animals only.
Omnivore: Eats both plants and animals.

Question 5

What is a decomposer?

Answer 5

An organism, like bacteria or fungi, that breaks down dead matter, returning nutrients to the ecosystem.

Question 6

What is biodiversity?

Answer 6

The variety of living organisms in an ecosystem.

Question 7

What is the difference between population and community?

Answer 7

Population: A group of the same species in an area.

Community: All populations of different species in an area.

Question 8

What are the levels of ecological organization?

Answer 8

Individual → Population → Community → Ecosystem → Biome → Biosphere.

Question 9

What is the difference between a food chain and a food web?

Answer 9

Food chain: Shows a single path of energy transfer.

Food web: Shows interconnected food chains in an ecosystem.

Question 10

Define photosynthesis.

Answer 10

The process in plants that uses sunlight, water, and carbon dioxide to produce glucose and oxygen.

Question 11

What are the methods for estimating populations?

Answer 11

Quadrats: Sampling a defined area.

Transects: Observing distribution along a line.

Capture-tag-recapture: Tagging animals and estimating populations based on recaptures.

Question 12

What is mutualism?

Answer 12

A relationship where both organisms benefit.

Question 13

What is commensalism?

Answer 13

A relationship where one organism benefits, and the other is unaffected.

Question 14

What is parasitism?

Answer 14

A relationship where one organism benefits (the parasite) and the other is harmed.

Question 15

What factors affect the distribution and abundance of organisms?

Answer 15

Physical factors: Temperature, rainfall, wind, light intensity.

Chemical factors: pH, salinity.

Biological factors: Competition, predation, and symbiotic relationships.

Question 16

What is the carbon cycle?

Answer 16

Carbon is absorbed by plants for photosynthesis.

Animals consume plants, transferring carbon.

Respiration and decomposition release carbon back into the atmosphere.

Question 17

What is the role of decomposers in the carbon cycle?

Answer 17

Decomposers break down dead organisms, returning carbon to the soil and atmosphere.

Question 18

What is a scavenger?

Answer 18

An animal that feeds on the decaying remains of dead organisms.

Question 19

What is the significance of photosynthesis and respiration in an ecosystem?

Answer 19

Photosynthesis produces oxygen and glucose, supporting life.

Respiration uses glucose and oxygen to release energy for growth and repair.

Question 20

Define adaptation.

Answer 20

A trait or behavior that helps an organism survive and reproduce in its environment.

Question 21

What is an ecosystem, and what are its key components?

Answer 21

An ecosystem consists of all the biotic (living) and abiotic (non-living) factors in an area and their interactions. Key components include producers, consumers, decomposers, and the environment.

Question 22

How do abiotic factors influence ecosystems?

Answer 22

Abiotic factors, such as temperature, light intensity, water availability, pH, and salinity, affect the growth, distribution, and survival of organisms.

Question 23

What is the difference between a habitat and a niche?

Answer 23

Habitat: The physical place where an organism lives.

Niche: The role and position an organism has in its environment, including its interactions with other organisms.

Question 24

What is a trophic level?

Answer 24

A trophic level represents the position of an organism in a food chain, such as:

Producers (Trophic Level 1).
Primary consumers (Trophic Level 2).
Secondary consumers (Trophic Level 3).
Tertiary consumers and apex predators (higher levels).

Question 25

How do energy transfers occur in ecosystems?

Answer 25

Energy is transferred through feeding relationships: Producers capture energy from sunlight. Consumers eat producers or other consumers. Energy decreases at each level due to heat loss and metabolic processes.

Question 26

What is the role of decomposers in an ecosystem?

Answer 26

Decomposers, such as fungi and bacteria, break down organic matter into simpler substances, recycling nutrients like nitrogen and carbon back into the soil and air.

Question 27

Describe the nitrogen cycle.

Answer 27

Nitrogen fixation: Bacteria in the soil convert atmospheric nitrogen (N₂) into forms plants can use, like ammonia. Nitrification: Other bacteria convert ammonia into nitrates and nitrites. Assimilation: Plants absorb nitrates and use them to make proteins. Decomposition: Dead organisms and waste return nitrogen to the soil. Denitrification: Bacteria convert nitrates back to nitrogen gas, releasing it into the atmosphere.

Question 28

What are the methods of measuring population abundance?

Answer 28

Quadrats: Count organisms in small, marked areas and extrapolate. Transects: Record organisms along a line to measure changes in distribution. Capture-tag-recapture: Tag animals, release them, and recapture to estimate population size using the formula: Total population = (Number of marked animals × Total animals recaptured) / Marked animals recaptured.

Question 29

What are limiting factors in an ecosystem?

Answer 29

Factors that restrict population growth, such as food availability, water, shelter, space, and competition for resources.

Question 30

What are the main types of symbiotic relationships?

Answer 30

Mutualism: Both organisms benefit (e.g., bees pollinating flowers). Commensalism: One organism benefits, the other is unaffected (e.g., barnacles on whales). Parasitism: One organism benefits while the other is harmed (e.g., ticks on mammals).

Question 31

What are invasive species, and why are they a problem?

Answer 31

Invasive species are non-native organisms that reproduce rapidly, outcompete native species, and disrupt ecosystems.

Question 32

Explain the water cycle.

Answer 32

Evaporation: Water from oceans and lakes turns into vapor. Condensation: Water vapor cools and forms clouds. Precipitation: Water falls as rain, snow, or hail. Runoff: Water returns to bodies of water, completing the cycle.

Question 33

What is ecological succession?

Answer 33

A gradual process of ecosystem development: Primary succession: Starts in barren areas with no soil (e.g., volcanic rock). Secondary succession: Occurs in areas with soil after a disturbance (e.g., after a forest fire).

Question 34

How does human activity impact ecosystems?

Answer 34

Deforestation: Reduces biodiversity and disrupts carbon storage. Pollution: Harms organisms and changes abiotic conditions. Urbanization: Leads to habitat loss and fragmentation. Overfishing: Disrupts aquatic food chains.

Question 35

What is the role of photosynthesis in ecosystems?

Answer 35

Photosynthesis converts sunlight, carbon dioxide, and water into glucose (for energy) and oxygen, supporting life in ecosystems.

Question 36

How does climate change affect ecosystems?

Answer 36

Alters species distribution and migration. Increases extinction risks due to habitat loss. Changes abiotic factors like temperature and precipitation.

Question 37

Define carrying capacity.

Answer 37

The maximum population size of a species that an environment can sustainably support based on available resources.

Question 38

What are food chains and food webs?

Answer 38

Food chain: A linear flow of energy from producers to top predators. Food web: A complex network of interlinked food chains showing all feeding relationships in an ecosystem.

Question 39

What is the carbon cycle?

Answer 39

Plants absorb CO₂ for photosynthesis. Animals consume plants, transferring carbon. Respiration and decomposition release CO₂ back into the atmosphere. Fossil fuels release carbon when burned.

Question 40

Why is biodiversity important?

Answer 40

Biodiversity ensures ecosystem stability, resilience, and the availability of resources like food, medicine, and clean water.