Unit 7: What is an ecosystem?

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2 Unit 7: What is an ecosystem? Lesson 20 An ecosystem is an area or habitat that contains living and non-living things. The living and non-living things depend on each other in many different ways. An ecosystem works like a smooth-running engine, provided people do not interfere with or harm it. The living things are plants, animals and micro-organisms, such as fungi, moulds and bacteria. The non-living things are air, water, sunlight and soil. An ecosystem There are many different ecosystems, such as mountains, grasslands, forests, deserts, rivers, ponds, wetlands, rocky shores and seas, which all support different kinds of living things. This term, we will focus on two ecosystems. Rocky shore ecosystems. The rocky shore has a lot of wildlife. It is home to animals such as fish, crabs, jumping sea lice and slow-moving anemones, sea urchins, sea snails and limpets. The rocky shore ecosystem is also home to animals such as barnacles, limpets and sea anemones, and plants such as seaweed. At high tide the rocks are covered by water and at low tide the rocks are exposed to the Sun. The mussels and barnacles sieve little bits of food from the water when it washes over them. To protect themselves, they close their shells tightly shut when it is dry. The limpets eat seaweed. They leave their shells to search for food. Sea birds, such as seagulls and oysters catchers, catch and then crack open the mussels and limpets. Rocky Shore Ecosystem

3 Commonly found plants and animals in the Rocky Shore Ecosystem Activity 20 Draw and label a rocky shore ecosystem Lesson 21 Desert ecosystems. Desert ecosystems are hot and dry. But, the plants and animals that make up these ecosystems can cope with the harsh conditions. Tsamma melons are an essential plant in the Kalahari s semi-desert ecosystem. They look like watermelons, although they are bitter and do not taste very much like watermelons. For many animals, though, they are an essential source of water. The melon vines grow quickly after the rains, storing the water in their fruits.

4 These ripen during the dry winter season, just when the animals are getting a little thirsty. Brown hyenas, gemsbok, ground squirrels, striped mice and weaver birds all depend on the Tsamma melon plants. The gemsbok dig up the long fat roots for water. The rodents eat the seeds. The hyenas help to spread the seeds in their dung. The seeds are nicely hidden and protected from the rodents. It all fits together well. Activity 21 Learn more about the rocky shore and desert ecosystems. 1. Draw a desert ecosystem. Search Google images to help you find information. 2. Use the internet to read about and research the rocky shore and desert ecosystems Lesson 22 Study an ecosystem Group work. In Grade 4, you studied a habitat. This year, you are going to look more closely for links and relationships between the plants and animals and their resources in the habitat.

5 Aim In this activity you will look for links between plants and animals in an ecosystem. Method Step 1 Select part of an ecosystem on or near the school grounds. Roughly measure an area of 5m by 5m, and mark out the four corners with stones or sticks. Step 2 Make notes that describe the habitat s resources, such as food, water, amount of sunlight and available shelter. Step 3 Identify and draw three plants and three animals. Activity 22 Questions 1. Look for signs of feeding on each of the three plants. Identify what has been eating them and which parts of the plants have been eaten. 2. State what each of the three animals eat. 2.1 ) Name the sort of animal that would eat each of these animals 2.2 ) Explain how these animals and plants depend on each other for food. 3. Identify and describe possible threats to your ecosystem. (Consider things such as noise, litter, foot traffic, plants cover or wild cats.) 3.1 ) Suggest possible ways to overcome the threat or problem

6 Lesson 23 Activity 23 Find out more about different ecosystems. Individual work. Research one of the ecosystems and present it to the class, in the form of a poster. Include the following: The non-living things that support life ( water, air, sunlight, and shelter) The living things and the non-living things that are dependent on each other. The feeding relationships in the ecosystem. The threats to this ecosystem.