7.2Chapter 7: The Health of the Environment

Habitats within an ecosystem — Alhussan Biology - Stage 8 Revision Notes & Topical Questions

5 min read 9 parts Lesson 2 of 8 2 quizzes

📚 Alhussan Biology - Stage 8 Hub / Topical Revision

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7.2 Habitats within an ecosystem — Alhussan International Academy — Biology (Stages 7–9) notes: Define habitat, population, community and niche, and explain how organisms are adapted to different habitats within one ecosystem.Habitat = the place where an organism lives, its home.…

Abiotic factors
Every tree is a small ecosystem
Parts of a tree
Leaf litter and soil
Tree canopy
Rocky shore

Part 1 of 7Habitat, population and community

Habitat, population and community

Habitat

Habitat the place where an organism lives, its home.

An ecosystem such as a woodland contains many different habitats, for example leaf litter, tree canopy, a pond or the soil.

Population

Population all the organisms of one species living in a habitat.

Community

Community all the populations of different species living together in the same habitat.

Ecosystem

Ecosystem it includes the community together with the non-living environment.

Niche

Niche the job an organism does in its habitat, such as seed eater, nectar feeder or decomposer.

Organisms in a habitat each have their own niche so that they avoid competing for food.

Part 2 of 7Abiotic and biotic factors

Abiotic factors

Abiotic factors they are non-living, such as light intensity, temperature, water availability, pH and wind.

Biotic factors

Biotic factors they are living, such as competition, predation, disease and food supply.

Conditions decide which organisms can live in a habitat.

The woodland floor is dark and damp, so shade-tolerant ferns and mosses and moisture-loving woodlice live there.
The woodland canopy receives full sunlight, so many insects and birds live there.

Part 3 of 7A tree as a habitat

A tree as a habitat

Every tree is a small ecosystem

Every tree is a small ecosystem some species of tree are home to hundreds of other species.
A single tree may contain around 1000 different habitats.

Parts of a tree

Parts of a tree each gives a different habitat.
The leaf canopy, branches, flowers and fruit are home to bees, wasps, moths, squirrels, sparrows and hawks.
The trunk and bark are home to insects and larvae.
The roots spread through the soil and are home to organisms such as tarantulas.
Leaf litter and decaying leaves support frogs and fungi.

Part 4 of 7Different habitats, different adaptations

Pond

Pond water lilies have flat floating leaves with stomata on the upper surface, and fish have gills and streamlined bodies.

Leaf litter and soil

Leaf litter and soil earthworms have soft bodies that burrow and improve soil aeration, and woodlice avoid dry conditions.

Tree canopy

Tree canopy birds have wings and keen eyesight, and leaves have a large surface area to capture light.

Rocky shore

Rocky shore limpets clamp to rock to avoid being washed away and to hold in water at low tide.

Part 5 of 7Larger ecosystems and their habitats

Larger ecosystems and their habitats

Lake

Lake it has different habitats at all levels of the water.
Light and temperature affect which species live there.
The bottom has habitats under stones and among water weeds, and the edge ranges from reed beds to shingle shores.

African savannah

African savannah habitats range from huge grasslands to dung.
The grasslands are home to large animals such as zebra, lions and elephants.
Dung is a rich habitat for bacteria, fungi (decomposers), worms and insects such as beetles.

Alpine mountain

Alpine mountain it is high and cold.
Habitats include bare rock, flat and sloping surfaces, and sunny and shady areas.
Organisms range from tiny plants on sheltered surfaces to birds of prey nesting on high ledges.

Part 6 of 7Investigating a habitat

Choose one factor to vary, for example a shaded and a sunny part of a field, and keep other factors the same.

Measure the abiotic factor, such as light with a light meter, at several points.

Place a quadrat at random and count the species and numbers of organisms.

Repeat in each area at least five times and calculate a mean to reduce the effect of chance.

Present results in a table, then a bar chart, and link the abiotic difference to the difference in organisms.

Part 7 of 7Habitats change with time

1Seasonal change

Seasonal change a pond in summer has warmer water with less dissolved oxygen,
- and a woodland floor receives more light in spring before the leaves open.

2Movement between habitats

Movement between habitats some animals use several habitats through the year, such as birds that nest in a wood and feed in a field.
Protecting an ecosystem therefore means protecting several connected habitats.

Key terms

Term	Meaning
Habitat	The place where an organism lives.
Population	All the organisms of one species in an area.
Community	All the populations living in the same habitat.
Niche	The role or job of an organism within its habitat.
Abiotic factor	A non-living part of the environment.
Biotic factor	A living part of the environment.