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ECOSYSTEMS YEAR NINE SCIENCE ECOLOGY: Students to Use Booklet- as well!-starter ex in booklet DEFINITIONS:-give sheet and add/fill in these interdependence- all living things rely on each other for survival Ecology-study of organisms interact with each other and their environment Interact- means they affect each other in some way Environment- all the factors in an organism’s life /surroundings that affect it. Habitat- area where animals live ECOSYSTEMS Where living organisms interact with each other and their physical environment Three main components Physical things-rocks/soil/water Living organisms Living and non living factors that make up the environment-gases, water supply etc Some ecosystems exist on their own-lake ecosystems etc Organisms are affected by two main sets of factors ABIOTIC AND BIOTIC FACTORS Abiotic-non-living Air, water, light quality/intensity, temperature, wind, soil type, humidity, waves, lightening fire! Biotic-living These are the living factors Predators-who is eating who Infectious organisms that affect others Competing organisms for food ABIOTIC IN DETAIL WATER-essential for all chemical reactions in cells and therefore essential for life Often the most vital factor for survival TEMPERATURE: Heat affects the speed of chemical reactions; often the higher the temp the less effective these reactions are or they won’t occur at all. Certain organisms have different optimum temps that they work best at! Fish/reptiles/amphibians-cold blooded but lie in the sun to get the correct temp for their cellular reactions to occur ECTOTHERMIC- Body heat is gained from the environment rather than from generating it inside the body. ENDOTHERMIC-Humans, birds and other mammals are called warm blooded as they have the ability to generate heat internally and control heat loss (think back to endocrine system and heat control) Could do activity page 283-FISH SHAPES CONT: FIRE- Some fires start by lightening Australian Aboriginals have used fire for ages to keep the bushland under control/open and improve the growth of plants There are some native plants which need the extreme heat/and chemicals released by the smoke of fire to open their seed pods and allow them to regenerate LIGHT-obviously photosynthesis Uses necessary for light, water and carbon dioxide to manufacture food AND THERE’S MORE! SOIL TYPE: not all soils are the same- some have more nutrients than others!-hold more water GAS LEVELS –Oxygen, is needed for respiration, usually enough in air but can change in water. Cold water has more oxygen than warm water Biotic factors Organisms do not live alone-surrounded by other living things-plants, animals and microorganisms The living things in an ecosystem form a community-and they interact with each other. The interactions between living things ARE THE BIOTIC factors Biotic factors in detail: COMPETITION: this when organisms compete for the same resource e.g. food Competition occurs between members of the same species There is limited resources and therefore some individuals will not survive. PREDATION- When one eats another!- a type of feeding relationship MUTUALISM: This is a relationship in which two organisms live closely together and both benefit. E.g. cleaner shrimp on the fish- the shrimp eat the parasites to keep the fish healthyone gets health the other food! Pollination is another example of mutualism-flowers depend on birds and insects to pollinate/results in seeds/more flowers reproduced. POLLINATION PARASITISM In this relationship one organism lives off another and feeds off it. The parasite doesn’t survive without the host and usually harms it in the process. E.g caterpillar attacked by a wasp. COMMENSALISM:-this is when one organisms benefits but the other is not harmed nor gains anything from the relationship –Strawberry poison arrow frog=raises young in bromeliad plants but doesn’t harm them ADAPTATIONS Adaptations are when an organisms has features that enable it to cope with the abiotic and biotic factors of its environment. The features are the adaptations- i.e long legs, fur colour, ability to concentrate urine in drought times, etc. Adaptations are divided into three categories: Structural Behavioural Functional/physiological Structural Adaptations This is when an organism has a body part that helps it survive a specific environment e.g. Wings to fly Sharp beak to catch food Behavioural Adaptations A feature of the organism’s habits e.g. Animals that only come out at night to feed-avoid the heat Dolphins that echolocation- send sounds that bounce off objects in the water to help them know what is near Functional Adaptations This is a feature that is involved with the way the organisms body works. E.g. When you exercise your heart beats fastergreater blood supply to muscles- functional because it is involuntary-you do not control it. Sometimes called physiological adaptations ADAPTATIONS PRACTICAL BOOKLET 9.2 SUSTAINABILITY This means the living conditions of an ecosystem can be maintained. FOOD- essential in any ecosystem for survival Contains the matter and energy needed by the organisms Ecosystems are described using feeding relationships-who eats who and what is the flow of energy PRODUCERS Every community has producers- the basic food source-green plants mainlysometimes bacteria-producers are absolutely essential for an ecosystems survival :NO PRODUCERS=NO LIFE CONSUMERS-Any organism that needs to eat another for survival is a consumer All the food we eat comes from a producer originally i.e bread from wheat etc photosynthesis Producers make their food via photosynthesis: A chemical process whereby carbon dioxide and light energy and water is converted to glucose and oxygen Occurs in the cells of plants in the chloroplasts which contain the substance chlorophyll Practical page 299-copied PHOTOSYNTHESIS Photosynthesis cont: In land plants carbon dioxide is absorbed form the air and the water through the roots Glucose that is made is vital for the plant The plants use it to make all the other molecules a plant needs to live like proteins, fats and vitamins Sugar/glucose is often turned to starch and stored in the leaves until the plant needs it again FOOD WEBS & CHAINS In communities we see food chains- who eats who and how is the energy passed on from the producer up the line/chain of consumers We see 1st order, 2nd order and 3 rd order consumers I WILL DO THESE ON BOARD- GET READY TO COPY PG 291 PEARSONS FOOD WEBS: - These are just a collection of “chains” and show the more complex feeding relationships within an ecosystem Pg 292 Food webs Recycling of Matter Most important in any food web are the decomposers. Fungi, and bacteria can break down dead and decomposing organisms and recycle the nutrients/matter for the producers to use. Without decomposers the ecosystems would not keep functioning. Draw fig 9.2.6 form Pearson pg 292 on board/in books Energy Flow in Ecosystems Energy doesn’t cycle through like matter does. Energy is continuous-lost as fast as it is gained Energy flows in this way: We eat because we need food for cells to grow and repair To provide us with energy to move In Ecosystems energy flows from one organism to another as it is eaten. Energy Flow Cont: Only the food held in the body cells of one organism is available as energy to the next in the chain or web This is because the organisms would have used lots of the energy it has taken in from eating to move and reproduce and grow etc. It is only 10% of all energy taken in by an organism that is actually available to the next level up the chain. It is the progressive loss of energy up a chain which makes them short-or only really up to about 4 consumers long after the producer. See next slide for diagram Energy Flow through a food chain Carnivore 1 kg Producer 1000kg Herbivore 100kg 0100 1000 Energy UNITS 900 units of Energy units energy lost units –used by mouse Carnivore 10kg 10 units 90 units lost- used by snake 9 energy units lostused by eagle Biomass Pyramid 1 kg Eagle 10 kg Of snakes 100 kg Of Mice 1000 kg of grass Biomass Pyramids Pyramids of Biomass show the total mass of organisms at each stage of a chain They are useful because they allow ecologists to understand total productivity of an area. Productivity means how well this area supports life. Comparing different ecosystems and their productivity is useful for farming, fisheries and wildlife conversation. BIODIVERSITY The range of different species in a community High biodiversity-lots of species-less affected by human impact/or environmental disruption to an ecosystem What sort of things can “invade” ecosystems: Foreign animals Foreign plants/weeds The more bio- diverse a community is less the effect of introduced species Other changes: Weather-may mean more flowers-more bees, as have more food to survive-more honey eaters etc.- therefore bird populations increase and eventually bee population decreases again- and then the birds will too eventually, decrease. Feeding patterns practical=coloured cards /discuss pg 295 ? Endangered species assignment 9.2 HUMAN IMPACT Many natural events affect ecosystems Seasonal changes Bushfires Droughts Floods Bushfires: Can be lit by humans Maybe lightning strikes Fires have affected for longer than humans have Often promotes the germination of plant species and therefore regeneration of natural forests in Australia. Bushfires cont: Eucalypts have oils that catch fire easily Litter fuels the fires Dead leaves etc do too Eucalypts also regenerate quickly and gives them an advantage over other species They are adapted in various ways Thick bark-insulates the cells underneath Other plants only return by seeds being dropped there by animals /birds etc Droughts Extended periods of no rainfall at all Changes to an ecosystem include increase death rate- at times to point of extinction Plant death removes food source for even more animals species Loss of plants-soil erosion Australia has regular droughts- but many organisms in these areas are adapted However-long droughts still cause death Flooding When water temporarily covers land not normally covered Rivers overflow banks- has occurred in Queensland, NSW etc. Floods affect ecosystems both negatively and positively Negative- death of native plants and animals due to drowning of roots/no oxygen or exposure Positive-new soil deposited, rapid plant growth-new species arrive-rapid growthmore food and so on… Human Impact Habitat destruction- housing/road building Logging Mining Is repairable if enough known about the ecosystem Some species have reducedRat kangaroo Potoroo Bilby Honey eater Introduced species Plants and animals that have been brought to Australia- not natural Some are predators Some established in the wild- FERALdomestic cats and foxes Rabbits Donkeys Goats etc Chemical pesticides Some of the early pesticides/insecticides used have been found to be more dangerous than to just the insects DDT increased along the food chain due to increased consumption of organisms below in a food chain. Birds badly affected-prevented eggs form developing-young died out-no adults=no species Humans accumulated it in breast milk if exposed-cancer, diabetes, reproductive issues Even though some don not accumulate still not safe and cause problems- can spread to other plants etc CHEMICAL POLLUTION Claims carbon dioxide is polluting earths atmosphere-global warming Enhanced green house effect Carbon dioxide absorbs some heat radiated by the earth –warming the atmosphere Some feel gases such as methane and even water vapour have issues too Some scientist argue against it all The problem is as: temperatures rise-polar ice caps melt-sea levels rise-land covered in water- death Over cropping No !! Not an issue with your editing skills! Killing more animals than can be replaced by normal breeding cycles Whale populations have been affected in this manner Blue whales are now protected but recovery is slow. Human endeavour-page 308+
