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Biosphere SG Biology How it works? The Biosphere Investigating an ecosystem Sampling and other measurement techniques applied to the investigation of an ecosystem. How it works Components of an ecosystem, energy flow, population growth, controlling factors. Control and management Intervention in the natural balance of an ecosystem; using understanding to manage ecosystems. Identification Think of a species (plant or animal) Write down a description of your species on a piece of card. Exchange the card with another member of the class. Could they identify the species you have described? Identification keys Identification keys help us to identify plants and animals. Have a look at the samples of keys available in class. The two types of key you could use are: Numerical key Branched key Complete the worksheet on identification keys Food Chains Watch the Scientific Eye video making notes on food chains, and factors affecting populations. Food Chains and Food Webs Environment and Feeding Definitions Herbivore: An animal that eats grass and other green plants in a food chain; Carnivore: A flesh-eating animal. Prey: An animal hunted or caught for food Predator: An organism that lives by preying on other organisms. Definitions Primary consumer: An animal that eats grass and other green plants in a food chain; an herbivore. Secondary consumer: An animal that feeds on smaller plant-eating animals in a food chain. tertiary consumer: An animal that feeds on secondary consumers in a food chain. Population: All the organisms of the same species living in the same place at the same time. Food Chains Food chains are one way of showing how organisms interact. For example: Grass Rabbit Fox The arrows represent the flow of energy (food) between organisms, it points from the eaten to the eater. All food chains start with plants, they use sunlight during photosynthesis to build up food (energy) stores, these are then passed on to animals. Important terms: Plants are producers because they produce their own food Animals are consumers because they eat food to obtain energy. There are 3 types of consumer Herbivores eat plants Carnivores eat other animals Omnivores eat plants and animals Organisms that breakdown dead plants and animals are called decomposers, e.g. fungi, bacteria and worms Producer PLANTS primary consumer HERBIVORE secondary consumer CARNIVORE tertiary consumer TOP CARNIVORE Food Webs When several food chains in a habitat are studied, some organisms appear in more than one. This is because most animals eat more than one type of food. If food chains in a habitat are linked, they form a FOOD WEB. Food web for a single tree Which are the primary and secondary consumers in this photograph? Competing for the same niche Biosphere How it works? Populations Adaptations Factors affecting population size Populations A population is a group of individuals of the same species living in a particular habitat at the same time. The number of individuals present in the population will depend on how they can interact with two types of factor. Populations Living factors – food, disease, predation, mates, effects of humans, and competition Non-living factors – water, oxygen, carbon dioxide, temperature and light Competition for Resources Plants and animals compete for resources. Plants often compete with each other for space, and for nutrients and water from the soil. Animals often compete with each other for space, water and food. Competition for Resources There are two types of competition: Intra-specific – competition between individuals of the same species Red deer stags fight to mate with the females Boobies compete for nesting space Competition for Resources Inter-specific – competition between individuals of different species. Garden birds compete for food in winter Plants compete for space, light, water and nutrients. Factors affecting population size A population is a group of individuals of the same species living in a particular habitat. Births and immigration increase the size of a population. Deaths and emigration decrease the size of a population. Factors affecting population size The size of a population, may also be affected by: The total amount of food and water available, if food supply is low, then individuals will compete for them. Oxygen shortage can limit numbers in a population that lives in water. Poisons can build up in the environment and limit population growth. Factors affecting population size List continued from previous page: Predation will limit the prey population. Disease can spread quickly through large populations. Climate – drought, flood and storms all affect population numbers. Lack of shelter Competition for light Population Graphs For one species in good conditions 4 Number of individuals 3 2 1 time For one population in good condition 1. Slow increase as only a few individuals. 2. Sharp increase, good conditions for growth 3. Some factors start to slow down increase (e.g. lack of food). 4. Stable population (birth rate = death rate) Predator-prey relationships Animals that kill and eat other animals are called predators. The animals that they eat are called prey. Predators are usually bigger and fewer in number than their prey. List five things that make a good predator: List five ways prey have adapted escape from predators: The graph shows the relationship between a predator and its prey. List what is happening in each of the stages 1 – 5 on the predator prey graph. 1. 2. 3. The prey has plenty of food. It breeds and increases in number. The increase in prey means that there is more food for the predator. So the predator breeds and increases in number. There are now lots of predators so more prey will be eaten. The number of prey goes down. Predator prey graph There are now less prey for the predator to feed on. Food will be scarce and many predators starve. 5. With fewer predators, more prey survive to breed. The prey numbers increase 4. The cycle continues… Adaptation The Biosphere How it works? Learning Outcomes To explain the terms ecosystem, habitat and community. To understand that physical factors affect animals living in an ecosystem To be able to explain how animals are adapted for survival in arctic and desert conditions. What is an Ecosystem? The Environment An ecosystem is an environment where living organisms can survive. The environment is made up of lots of different ecosystems, such as seashore, a wood or a river. Each ecosystem is made up Habitats and Communities Habitat - This is the place where the organisms live. It has the conditions that they need to survive. Community – all the living organisms that live in the habitat. Physical Factors Each ecosystem has a set of environmental factors. Availability of water Temperature - Few living organisms can grow outside the range of 0oC to 40oC. amount of Light - photosynthesis in plants, animals need light for visibility. Availability of carbon dioxide and oxygen These factors vary according to the time of day and the time of year. Adaptations Living things adapt to their environment. Watch the video clip, and then try to fill in the table explaining how the creature is adapted to it’s environment. Adaptations in different animals Look at the animals on the worksheet, for each one try to give where it lives and an example of how it is adapted for survival in its environment. Pupil Activity Surviving in different environments. Read all information carefully Answer questions 1 - 9 Camel designed for desert conditions A camel’s hump is a fat store. It can break down fat to release water. A camel can drink large amounts of water. Its mouth is tough so that it can eat thorny plants like cacti. Short hair underneath the camel lets heat escape. Coarse wool on top of its body protects the camel from the sun. Big flat feet stop it sinking into the sand. Adaptations to water loss a cactus in the desert Leaves reduced to spines – to reduce water loss through stoma Swollen stem stores water Wide spread root systems to increase surface area for absorption. Camel – designed for desert conditions A camel’s hump is a fat store. It can break down fat to release water. A camel can drink large amounts of water. Its mouth is tough so that it can eat thorny plants like cacti. Short hair underneath the camel lets heat escape. Coarse wool on top of its body protects the camel from the sun. Big flat feet stop it sinking into the sand. Adaptations to water loss - a cactus in the desert Leaves reduced to spines – to reduce water loss through stoma Swollen stem stores water Wide spread root systems to increase surface area for absorption. Class activity To draw labelled diagrams of a cactus, a camel and a polar bear which explain how they are adapted to their environment. Use one side of your exercise book for each diagram, and labels. Use the handouts to help you with the labels. Commendations will be awarded for exceptional work! Pupil Activity - extension Environmental factors affecting life Read all the information supplied on the sheet carefully. Answer questions 1 – 11 in full sentences.