Adaptations, Interdependence & Competition

Define the term population.

A population is a group of organisms of the same species living in the same place at the same time.

Define the term community.

A community includes all populations living in the same area at the same time.

True or False? A habitat is the place that an organism lives.

True. A habitat is where an organism lives, e.g. a meadow or woodland.

True or False? Living organisms only interact with living components.

False. Organisms interact with both living (biotic) and non-living (abiotic) components of their environment.

Define the term ecosystem.

An ecosystem is all the organisms living in an area and their interactions with biotic and abiotic factors.

True or False? Animals often compete for light, space, water and minerals.

False. Plants compete for light, space, water and minerals; animals compete for food, mates, and territory.

What is interdependence in ecosystems?

Interdependence means organisms in the same habitat depend on each other; a change in one species affects others.

When is a community stable?

A community is stable when biotic and abiotic components are balanced, and population sizes remain fairly constant.

Define the term abiotic factor.

Abiotic factors are non-living factors that influence ecosystems, e.g. temperature, sunlight, pH, salinity, precipitation.

Give examples of abiotic factors.

• Light intensity - Temperature - Water availability - Soil pH / moisture / minerals - Wind speed - CO₂ concentration - Water pH - Oxygen concentration

How might decreased water availability affect a population?

• Population size might decrease - Population may move to areas with more water

True or False? Increasing temperature from 20°C to 30°C increases plant population size.

True. Higher temperatures increase photosynthesis, promoting faster growth and larger population.

True or False? Competition is an abiotic factor.

False. Competition is a biotic factor.

Define the term biotic factor.

Biotic factors are living factors affecting organisms, such as competition, predation, and disease.

Give examples of biotic factors affecting populations.

• Predators - Competition - Availability of food - Pathogens/disease

True or False? Increase in prey population causes predator population to decrease.

False. A decrease in prey population usually causes predator populations to decrease due to lack of food.

Define competition in an ecosystem.

Competition occurs when organisms fight for the same resources, e.g. food or mates.

True or False? Populations competing for the same resources are likely smaller.

True. Competition can reduce population size; less well-adapted populations may die out.

Define the term adaptation.

An adaptation is a feature that improves an organism’s ability to survive in its environment.

Give examples of structural adaptations in desert plants.

• Spines instead of leaves to reduce water loss - Succulent stem to store water - Deep tap roots - Shallow roots to collect dew/rainfall

True or False? Large elephant ears are a functional adaptation.

False. Large ears are structural; functional adaptations involve physiological/biochemical processes like sweating.

Give examples of behavioural adaptations.

• Staying in cool burrows during the day, hunting at night - Digging burrows for nesting/protection - Huddling together to share heat in cold conditions

True or False? Small ears on arctic foxes are a structural adaptation to minimise heat loss.

True. Smaller ears reduce surface area, conserving heat in cold environments.

Define the term extremophile.

An extremophile is an organism living in extreme conditions, e.g. very high/low temperatures, high pressures, high salt concentrations.