KS3 Science. Ecology & Environment

Transcription

1 KS3 Science Ecology & Environment

2 8.1 Ecology & Environment Context In this topic you will discuss how various organisms impact on one another and their environments. You will also gain confidence carrying out appropriate sampling techniques, as part of wider ecological investigations. Content 1. Sampling a. Recall various sampling techniques (pitfall traps, sweep nets, pooters, quadrats & transects) b. Describe how to carry out various sampling techniques c. Suggest the use of an appropriate sampling technique for a given hypothesis d. Evaluate ecological studies in terms of their validity and reproducibility 2. Interdependence a. State examples of interdependent organisms b. Describe what food webs and chains show c. Explain how bioaccumulation occurs and its impacts on ecosystems d. Analyse data on predator/prey relationships e. Explain why pollinators are important to plant reproduction and food security 3. Factors that affect organisms and their environment a. State environmental factors that affect organisms (oxygen, CO 2, light, temperature, nutrients and water) b. Describe how organisms are adapted to their environments c. Use data to evaluate human impacts on the environment 2

3 Ecology & Environment Key Words Write a definition for each of the key words listed below Key words Organism Adaptation Environment Habitat Predator Prey Producer Consumer Food web Food Chain Bioaccumulation Interdependence Quadrat Pooter 3

4 1. Organisms & their environment Complete the sentences by using the words from the box ADAPTED ENVIRONMENT HABITAT ORGANISMS PHYSICAL Living things are called The area where an organism lives is called a The surroundings of an organism are called its The conditions in an environment are caused by environmental factors. Animals and plants have to be to the conditions where they live. Draw a line to match the organisms listed below to the habitat they live in. For each organism explain why you have matched them to a particular habitat. Giraffe Fox Squirrel Zebra Lion Robin Rhino Elephant Oak Tree Caterpillar 4

5 2. Adaptations In each environment on Earth we will find different organisms. Organisms have features that allow them to survive in their habitat. These features are called adaptations. Complete the table below to identify the environment the organism lives in and the adaptations each organism has that helps it to survive in the environment in which it lives Organism Habitat (Include a description of conditions) Adaptation ( Explain how this helps the organism to survive) Desert Fox Jaguar Polar Bear Camel Artic Hare 5

6 3. Food Chains Draw an arrow to match the words to the meanings Predator An organism which eats only vegetation Prey An organism which makes its own food from the sun Producer An organism which eats both vegetation and other animals Consumer An animal which hunts and eats other animals Herbivore An animal which eats other animals only Omnivore Carnivore An animal that us hunted and eaten by a predator An animal that eats other plants and/or animals An example of a food chain is shown below: Oak tree > Caterpillar > Black bird > fox What do the arrows mean in the food chain?.. Identify the herbivore, carnivore and producer. Copy down the following food chain examples into the correct order and label the producer, consumer, prey and predator. 1. Eagle, carrots, rabbit, snake 2. Dandelions, snail, bird, frog, fox 3. Grasshopper, frog, grass, eagle, snake 4. Hazel tree, wood mouse, tawny owl 5. Plankton, dolphin, tuna, snail 6

7 3. Food Webs Complete the sentences by using the words from the box DOWN WEB CHAINS UP When you have many food in a habitat then you can form a food If disease affects the top consumer, the number of secondary consumers goes If the amount of producers go down, the number of primary consumers will go Look at the food web above and answer the questions 1. Circle all the carnivores. 2. Write down all the food chains that start with a plant and end with a blue tit Explain what might happen to the number of ladybirds if the number of aphids decreased What might happen to the number of a moth larva and lady birds if disease kills the blue tits?... 7

8 4. Pyramids of number & biomass Here is an example of a food chain and a pyramid of numbers Answer the questions below. 1. Draw a food chain for the energy transfers below: A) dandelions (15), rabbits (3), fox (1) B) Cabbages (5), slugs (20), thrushes (5), cat (1) C) Grass (15), rabbit (1), fleas (50) 2. Draw a pyramid of numbers for each of the food chains you have drawn 3. What is an advantage of using a pyramid of numbers? 4. What is a disadvantage of using a pyramid of numbers? Energy is lost at each level of the food chain some of the energy us ysed by the animal or plant. 5. What might the plant or animal use energy for? 6. Write down some of the energy transfers that take place in the animal 8

9 4. Pyramids of number & biomass Look at the following food chains: Nettle plants > caterpillars > robins Rose bushes > greenfly > ladybirds Lettuces >slugs > Thrush 1. Using the information in the table below draw a pyramid of biomass for each food chain on the graph paper provided. Organism Biomass (kg) Organism Biomass (kg) Organism Nettle 18 Caterpillar 12 Robin 6 Rose bush 16 Greenfly 10 Ladybird 0.5 Lettuce 12.5 Slug 6 Thrush 3 Biomass (kg) You must draw your pyramids of biomass to scale, 1cm 2 = 1kg of biomass. Don t forget to include the name of the organisms at each stage of the pyramid 2. Once you have drawn your pyramids of biomass label the producers, primary and secondary consumers 9

10 4. Pyramids of number & biomass 10

11 5. Bioaccumulation Bioaccumulation is the build up of poisons in a food chain. DDT, a useful pesticide was found to have lots of toxic effects on the environment, especially birds. DDT is not easily broken down by the environment Assuming each leave contains one dose of DDT, mark on the diagram how DDT accumulates within a food chain Describe how DDT bioaccumulates in the food chain and explain what impact this has on the organisms. 11

12 5. Pollination & food security Put these images into the correct order in the cycle below to show the life cycle f a flowering plant, including how they are pollinated and fertilised. A B C D E F G 12

13 5. Pollination & food security All the food we eat relies on plants. This includes meat because animals such as pigs, sheep and cattle eat plants. Grasses such as wheat, barley and rice use the wind for pollination. Vegetables and plants that produce fruit rely on insects and other animals for their pollination. If the population of pollinating insects goes down, it reduces the amount of fruit for us to eat, and also the number of seeds for new crop plants to grow. Read through the information provided and use this to answer the question below. Are humans to blame for bees dying? In some areas, flowering plants are flowering earlier so there are big gaps between flowers that would normally flower one after the other. This prevents the bees from having a constant source of food. Many farmers still use pesticides on their crops in order to get more food. Pesticides kill most insects including bees. This reduces the amount of habitat that bees can use Varroa mites are becoming increasingly common in the UK and much of the world. They are parasites and feed on the bees themselves. This severely weakens individuals and the hive. These mites can kill the individuals slowly over several weeks. With many gardeners choosing to have decking in their garden, the amount of plants in the garden is decreasing. Lots of new houses are being built all the time and this decreases the amount of land available for flowering plants In 2012, the BBC reported that several counties in England were officially in a drought, due to low rainfall and dry conditions. Without rain, plants cannot grow quickly and make nectar during flowering. In the 1930s, the amount of beekeepers in the UK was 3 times more than it is today. Also, with fewer trees as suitable nest sites, bees have no where to live. 13

14 6. Sampling techniques Ecologists study an environment in terms of its biodiversity the variety of different species in an area. They will want to know certain information about the species present: Where an organism is found (distribution) The number of that organism present (population) Shade the boxes below in four different colours to match the sampling technique to the description and image 14

15 Summary Questions Answer the summary questions 1. Complete the sentences by crossing out the wrong words. The population size of daisies in a field can be obtained by using a quadrat/light meter. The number of daisies in a small area is guessed/counted and this number is used to estimate/count the number of daisies in the whole field 2. A. Name three resources that all living things compete for B. Explain how those resources can affect the number of organisms within a single population C. Name a non environmental factor that can also affect population size.. 3. Look at the food wed A. Name: A producer.. A primary consumer.. A secondary consumer. B. What happens to the number of organisms as you go along any food chain in the food web? Underline the correct answer: Increases Decreases Stays the same C. If one organism is removed from a food web what will happen to i. The number of organisms before it?... Ii. The number of organisms after it?.. 15