Ecology Flashcards
What is an ecosystem?
A group of organisms interacting with each other and their physical environment for survival.
What are biotic and abiotic factors?
Biotic factors: Living components (e.g., animals, plants, bacteria).
Abiotic factors: Non-living components (e.g., sunlight, water, rocks).
Define a producer.
An organism (usually a plant) that makes its own food through photosynthesis.
What is a consumer, and what are the three types?
A consumer eats other organisms for food. Types:
Herbivore: Eats plants only.
Carnivore: Eats animals only.
Omnivore: Eats both plants and animals.
What is a decomposer?
An organism, like bacteria or fungi, that breaks down dead matter, returning nutrients to the ecosystem.
What is biodiversity?
The variety of living organisms in an ecosystem.
What is the difference between population and community?
Population: A group of the same species in an area.
Community: All populations of different species in an area.
What are the levels of ecological organization?
Individual → Population → Community → Ecosystem → Biome → Biosphere.
What is the difference between a food chain and a food web?
Food chain: Shows a single path of energy transfer.
Food web: Shows interconnected food chains in an ecosystem.
Define photosynthesis.
The process in plants that uses sunlight, water, and carbon dioxide to produce glucose and oxygen.
What are the methods for estimating populations?
Quadrats: Sampling a defined area.
Transects: Observing distribution along a line.
Capture-tag-recapture: Tagging animals and estimating populations based on recaptures.
What is mutualism?
A relationship where both organisms benefit.
What is commensalism?
A relationship where one organism benefits, and the other is unaffected.
What is parasitism?
A relationship where one organism benefits (the parasite) and the other is harmed.
What factors affect the distribution and abundance of organisms?
Physical factors: Temperature, rainfall, wind, light intensity.
Chemical factors: pH, salinity.
Biological factors: Competition, predation, and symbiotic relationships.
What is the carbon cycle?
Carbon is absorbed by plants for photosynthesis.
Animals consume plants, transferring carbon.
Respiration and decomposition release carbon back into the atmosphere.
What is the role of decomposers in the carbon cycle?
Decomposers break down dead organisms, returning carbon to the soil and atmosphere.
What is a scavenger?
An animal that feeds on the decaying remains of dead organisms.
What is the significance of photosynthesis and respiration in an ecosystem?
Photosynthesis produces oxygen and glucose, supporting life.
Respiration uses glucose and oxygen to release energy for growth and repair.
Define adaptation.
A trait or behavior that helps an organism survive and reproduce in its environment.
What is an ecosystem, and what are its key components?
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.
How do abiotic factors influence ecosystems?
Abiotic factors, such as temperature, light intensity, water availability, pH, and salinity, affect the growth, distribution, and survival of organisms.
What is the difference between a habitat and a niche?
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.
What is a trophic level?
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).
How do energy transfers occur in ecosystems?
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.
What is the role of decomposers in an ecosystem?
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.
Describe the nitrogen cycle.
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.
What are the methods of measuring population abundance?
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.
What are limiting factors in an ecosystem?
Factors that restrict population growth, such as food availability, water, shelter, space, and competition for resources.
What are the main types of symbiotic relationships?
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).
What are invasive species, and why are they a problem?
Invasive species are non-native organisms that reproduce rapidly, outcompete native species, and disrupt ecosystems.
Explain the water cycle.
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.
What is ecological succession?
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).
How does human activity impact ecosystems?
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.
What is the role of photosynthesis in ecosystems?
Photosynthesis converts sunlight, carbon dioxide, and water into glucose (for energy) and oxygen, supporting life in ecosystems.
How does climate change affect ecosystems?
Alters species distribution and migration.
Increases extinction risks due to habitat loss.
Changes abiotic factors like temperature and precipitation.
Define carrying capacity.
The maximum population size of a species that an environment can sustainably support based on available resources.
What are food chains and food webs?
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.
What is the carbon cycle?
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.
Why is biodiversity important?
Biodiversity ensures ecosystem stability, resilience, and the availability of resources like food, medicine, and clean water.
