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2/6/2013 February 6, 2013 Ecology Study Island lesson: 3e and 3f Please close all other apps & web pages. No Facebook, games, music, etc. No off-topic chat Be respectful of each other Don’t share personal information I can see all chat … even “private chat” OH Grade 6-8, Science Standard Ground rules Standard I can statements Ecology Exit statement File transfer Questions Life Sciences D Explain how extinction of a species occurs when the environment changes and its adaptive characteristics are insufficient to allow survival (as seen in evidence of the fossil record). Covered by topics: Adaptation & Natural Selection Ecosystems: Energy Transfer & Population Dynamics Environmental Changes & Extinction I can… • Explain how organisms interact with each other and what happens as a result of abiotic and biotic factors • Describe how population dynamics works and be able to describe examples Ecology is the study of relationships between living things and between living things and their environment. 1 2/6/2013 Ecosystem is a system of living things that interact with each other and with the physical world. Rabbits were introduced to Australia in 1859. With only 24 rabbits, the population exploded to cover the whole continent in 40 years. Problems: Destruction of vegetation and extinction of some plant species Soil erosion Extinction of native animals like the bilby and the bandicoot A Biome is a collection of related ecosystems. Solutions: Build a fence so they stay in one area Introduce a disease to kill off the over-abundance. In 1950, the myxomatosis virus initially wiped out between 95 and 100% of rabbits in some areas. Problem: rabbits became immune to the disease Killed off too many, leaving some predators starving http://www.animalcontrol.com.au/rabbit.htm Desert Rainforest Ocean Taiga Tundra Chaparral Grassland Temperate Forest 2 2/6/2013 Are nonliving physical factors of an environment. An ecosystem can be as large as the Sahara Desert, or as small as a puddle!!! Ecosystems are more than just the organisms they contain. Geography, weather, climate and geologic factors also influence the interactions within an ecosystem. List three more examples of Abiotic Factors: Abiotoic Factors include amount of water and oxygen, temperature, amount of sunlight and water pressure. The abiotic factors of an ecosystem often determine what living things can live there. For example, animals that can survive in the Arctic are adapted to cold climates, while animals that can survive in deserts are adapted to dry climates. The abiotic factors of an ecosystem also provide most of the basic needs of plants and animals. So what lives here?? This place was a bit too……………………. Hot, Dry but at least you don’t get bothered by people 3 2/6/2013 I do It’s the right temperature and no-one but no-one messes with me Are the living, physical factors of an environment. The place in which an organism lives provides Plants and fungi are both biotic components of this ecosystem. the kinds of food and shelter, the temperature, and the amount of moisture the organism needs to survive 4 2/6/2013 Ecosystems will fail if they do not remain in balance. No community can carry more organisms than its food, water and shelter can accommodate. A food chain is a simple model of the feeding relationship in an ecosystem. To succeed in an ecosystem, plants and animals have special structures and behaviors called adaptations. Ex) Chameleon Polar Bear Can you think of more examples of adaptation? For example, shrubs are food for deer, and deer are food for mountain lions. The mountain lion is Shrubs are the beginning of the food chain. They receive their energy from sunlight. Producer The deer is the first organism of the food chain to eat the shrub. It is the primary consumer. the second organism of the food chain. It eats the deer. It is the secondary consumer. 5 2/6/2013 The first organism in a food chain is always a producer. They make their own food. A food web is a group of interconnected food chains. Organisms within a food web can belong to more than one trophic level, or feeding level. All the organisms in an ecosystem that belong to the same species All the populations in an ecosystem 6 2/6/2013 Populations of organisms do not grow linearly. That is, graphs of their populations do not form a straight line. Instead, populations grow exponentially because the more organisms there are, the faster the population grows. The presence of predators usually increases the number of different species that can live in an ecosystem. Predators limit the size of prey populations. As a result, food and other resources are less likely to become scarce, and competition between species is reduced. Needed resources that are present in limited quantities Can be abiotic or biotic Reproduction rates or the presence of disease Availability of good soil or lack of direct sun Competition for food Over-hunting or chemical spills Different ecosystems can have different limiting factors • • • • • • • • The maximum number of individuals of a population that a particular environment can support for a long time. As a growing population reaches the limits of the available resources in an environment, its size levels off to "match" the amount of resources available. When this happens, the population has reached its carrying capacity. For example, if the major food source of a population dies out, the carrying capacity for that population will drop. Conversely, an increase in available food can cause the carrying capacity for an organism to increase. The pattern of population growth will vary as environmental conditions change. These changes could include: a change in the food supply a change in the water supply a disease epidemic the creation of new vaccines a change in temperature storms, earthquakes, and other natural disasters crowding and competition predator-prey relationships 7 2/6/2013 Populations in an ecosystem affect one another. A change in the number of one type of organism will cause a change in the number of other types of organisms. These changes can be studied by looking at the population dynamics of an ecosystem. Example of a food web: Antelopes depend on the leaves from the tree as their food source. The wild dog and the lion compete with each other for the antelope. Another example would be if humans hunted and killed many of the African wild dogs and lions. This would cause an increase in the antelope population because they would not have as many predators. More antelope means they would eat more leaves from trees. This would decrease the amount of leaves, which is a resource. If a drought in the ecosystem caused many of the trees to die, there would not be enough food for all of the antelope to survive. The antelope population would decrease. If the antelope population decreased, the number of African wild dogs and lions would also likely decrease because they would be losing a major food source. All populations within an ecosystem are related in some way. This means that a change in even one population in an ecosystem can have drastic effects on the ecosystem as a whole. Section Summary • A food chain models the feeding relationships between species. http://www.learner.org/courses/envsci/interactives/ecology/food_web.php 8 2/6/2013 Section Summary Section Summary • Consumers cannot make food. They obtain energy by eating producers and other consumers. • Ecosystems are maintained by the population growth staying at a steady balance. Section Summary Links • When the carrying capacity of an Ecosystem is reached, something has to change; birth rate, death rate http://www.teachersdomain.org/resource/lsps07.sci.life.eco.oceanfoodweb/ http://www.learner.org/courses/envsci/interactives/ecology/producers_1.php http://www.harcourtschool.com/activity/food/food_menu.html Be sure to do a Pathway a Day. Don’t forget Math Pathways! Science SI: 3e and 3f this week. I think I am an expert I think I have a good idea ? I think I have got some of it Help – can you go through it again 9 2/6/2013 1. 3. 2. 10