Ecosystems 1 of 33 Boardworks Ltd 2008 Habitats

Ecosystems 1 of 33 © Boardworks Ltd 2008

Habitats 2 of 33 © Boardworks Ltd 2008

What is an ecosystem? The environment is made of many different types of ecosystems, such as seashores, forests, lakes and deserts. Each ecosystem can be divided into a: l habitat – the non-living part, i. e. the physical area in which organisms live l community – the living part, i. e. all the different organisms living in that particular habitat. 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. 3 of 33 © Boardworks Ltd 2008

What is a habitat? What makes a 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. How would you describe your habitat? 4 of 33 © Boardworks Ltd 2008

Different types of habitats How are these habitats similar and how are they different? 5 of 33 © Boardworks Ltd 2008

Which land habitat? 6 of 33 © Boardworks Ltd 2008

Which water habitat? 7 of 33 © Boardworks Ltd 2008

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: l quadrat l line transect l belt transect l trapping. 8 of 33 © Boardworks Ltd 2008

Sampling a population 9 of 33 © Boardworks Ltd 2008

Adaptations 10 of 33 © Boardworks Ltd 2008

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. 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! Some adaptations are obvious while others are not so obvious. Can you think of any other adaptations that you have? 11 of 33 © Boardworks Ltd 2008

Adaptations in different habitats These organisms are all adapted to their environments in very different ways. How are they specially adapted to survive? 12 of 33 © Boardworks Ltd 2008

Adaptations in similar habitats 13 of 33 © Boardworks Ltd 2008

What are adaptations for? 14 of 33 © Boardworks Ltd 2008

A new species… Scientists have discovered this strange new species on a small island off the coast of Argentina. The scientists want you to help them describe: l where this animal lives (land, water or air) l what it eats and how it eats l how it breathes l how it moves l what they should call it. 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! 15 of 33 © Boardworks Ltd 2008

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. 16 of 33 © Boardworks Ltd 2008

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. 17 of 33 © Boardworks Ltd 2008

Daily or yearly? 18 of 33 © Boardworks Ltd 2008

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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. 20 of 33 © Boardworks Ltd 2008

Why is important to conserve species? Extinction 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. 21 of 33 © Boardworks Ltd 2008

Biodiversity 22 of 33 © Boardworks Ltd 2008

Humans impact on environment 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: l destruction of natural habitats l over-hunting l climate change l pollution. 23 of 33 © Boardworks Ltd 2008

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 24 of 33 1985 2000 2005 © Boardworks Ltd 2008

Environmental effects of climate change Human activity may be causing a change in the world’s climate. 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. This change in the earth’s climate could result in: l higher global temperatures l sea level rising l a different geographical distribution of rain fall. 25 of 33 © Boardworks Ltd 2008

How could change affect ecosystems? 26 of 33 © Boardworks Ltd 2008

The effect of change on polar bears 27 of 33 © Boardworks Ltd 2008

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? 28 of 33 © Boardworks Ltd 2008