1 of 33© Boardworks Ltd 2008 Ecosystems. 2 of 33© Boardworks Ltd 2008 Habitats

1 of 33 © Boardworks Ltd 2008

Ecosystems


Habitats


What is an ecosystem?

Each ecosystem can be divided into a:

community – the living part, i.e. all the different organisms living in that particular habitat.

habitat – the non-living part, i.e. the physical area in which organisms live

Each community is made up of many different populations. A population is all the members of a particular species living in one habitat – for example, the population of red squirrels in an oak wood.

The environment is made of many different types of ecosystems, such as seashores, forests, lakes and deserts.


What is a habitat?

What makes a habitat?

How would you describe your habitat?

A habitat has all of the things that an organism needs to survive, such as the right amounts of oxygen, water, light and shelter.


Different types of habitats

How are these habitats similar and how are they different?


Which land habitat?


Which water habitat?


Sampling in a habitat

Ecosystems are constantly changing. In order to tell how the populations within a community change over time, you first need to establish how many organisms there actually are.

It would be impossible to count all the individual organisms in a habitat by hand. Instead we can count just a sample from a small area and multiply this by the total area of the habitat. This gives an estimate of the total number of the population.

Common sampling methods include: quadrat line transect belt transect trapping.


Sampling a population


Adaptations


What are adaptations?

Each type of organism has special features that help it to survive in its particular habitat. These special features are called adaptations.

Can you think of any other adaptations that you have?

Some adaptations are obvious while others are not so obvious.

For example, you have plenty of adaptations to survive in your habitat. Your fingers are an excellent adaptation – without the ability to grip, you would not be able to do all that schoolwork!


Adaptations in different habitats

These organisms are all adapted to their environments in very different ways.

How are they specially adapted to survive?


Adaptations in similar habitats


What are adaptations for?


A new species…

As the organism is adapted to its environment, you should be able to use the way it looks to answer all of these questions. Don’t forget to give your organism a name!

Scientists have discovered this strange new species on a small island off the coast of Argentina.

The scientists want you to help them describe:

where this animal lives (land, water or air)

what it eats and how it eats

how it breathes

how it moves

what they should call it.


Daily adaptations

Many features of the environment change on a daily basis, such as the temperature and the amount of light.

For example, many flowers open their petals during the day to catch the sun and close them at night to protect against the early morning frost.

Organisms are adapted to the type of habitat they live in and also to the daily changes that occur in that habitat.


Yearly adaptations

The environment also changes on a yearly basis with the seasons. This may bring about changes in light and temperature, but also in the availability of food and water.

Organisms have to adapt to these yearly changes; they have come up with many different ways to achieve this.

For example, some animals hibernate over winter to deal with food shortages.


Daily or yearly?



Effects of environmental change

Animals are adapted to suit their environment, helping them survive and reproduce. However if the environment changes they may no longer have this advantage.

A change in environment can cause extinction. Extinction is when the last individual of a species dies.

When a species is at risk of extinction, it is endangered. Over 1,100 animal species and over 700 plant species are classed as endangered or threatened.


Why is important to conserve species?

Extinction can cause a decrease in biodiversity. Biodiversity is the number and variety of organisms found in an area.

Conserving biodiversity is important as every living thing plays a vital role in an ecosystem. If one species becomes extinct this can have a huge impact on the rest of the community.

Extinction can also decrease the resources available to humans. For example, some medicines are made from plants – if a plant species becomes extinct its unique chemicals are no longer available to us.


Biodiversity


Humans impact on environment

destruction of natural habitats

over-hunting

climate change

pollution.

Extinction can occur naturally, however human impact on the environment can also cause species to die out.

Human activity can cause damage to the environment in several different ways:


Deforestation

Humans often destroy forest habitats to make room for housing or industry. This is called deforestation.

If a woodland habitat is destroyed some animals may no longer have resources they need, e.g. food and shelter. Species that aren’t able to survive outside of their natural environment may become endangered.

In Borneo, southeast Asia, forests are slowly being removed to make way for other crops.

1950 1985 2000 2005


Environmental effects of climate change

higher global temperatures

Human activity may be causing a change in the world’s climate.

This change in the earth’s climate could result in:

The production of carbon dioxide, and other heat-trapping gases from the burning of fossil fuels may be causing the earth’s climate to change. This is called the greenhouse effect.

a different geographical distribution of rain fall.

sea level rising


How could change affect ecosystems?


The effect of change on polar bears


Extinction due to climate change

If climate change causes an impact on habitats and ecosystems this could result in more species becoming extinct.

It is thought that 20–30% of species are likely to be at risk of extinction if the global average temperature rises by 1.5–2.5 °C beyond 1990 levels.

What evidence is there that global temperatures are rising?


Evidence for global temperature change



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1 of 33© Boardworks Ltd 2008 Ecosystems. 2 of 33© Boardworks Ltd 2008 Habitats