What is an ecosystem? What kinds of ecosystems do you know of?

1. Think... • What is an ecosystem? • What kinds of ecosystems do you know of?

2. An ecosystem is all of the living and nonliving things that interact in a particular area. • Organisms live in a specific place within an ecosystem. • An organism obtains food, water, shelter and other things it needs to live, grow and reproduce from its surroundings.

3. Prairie Dog • The place where an organism lives and that provides the things the organism needs is called its habitat. • Organisms live in different habitats because they have different requirements for survival. • Example: the prairie dog could not survive in a tropical rain forest or on the rocky ocean floor

4. Niche • An organism’s particular role, or how it makes its living, is called its niche. • A niche includes: • The type of food the organism eats • How it obtains the food • Which other species use the organism as food • When and how the organism reproduces

5. Compare and contrast a habitat and a niche. Niche Habitat

6. Biotic Factors • The living parts of an ecosystem are called biotic factors. • What are the biotic factors can you identify in the above picture?

7. Abiotic Factors • The nonliving parts of an ecosystem are called abiotic factors. • Abiotic factors also affect living things in the ecosystem. • What are some abiotic factors that could be found in an ecosystem? Water, sunlight, oxygen, temperature, soil

8. Populations • A species is a group of organisms that are physically similar and can reproduce with each other. • All the members of one species in a particular area are referred to as a population. • Example: all the pigeons in New York city make up a population and all the daisies in a field make up a population

9. Do all of the trees in a forest make up a population? Why or why not? No, because they do not all belong to the same species. Some of the trees may be pines, maples, etc.

10. Limiting Factors • A limiting factor is an environmental factor that prevents a population from increasing. • Some limiting factors for populations are food, space, and weather conditions. • Example: a flood or hurricane can wash away nests and burrows

11. Carrying Capacity • The largest population that an environment can support. • Example: • Suppose a giraffe needs 10 kg of leaves per day to survive. Trees in the area can provide 100 kg of leaves per day. Five giraffes could easily live in this area (since that is only a total of 50 kg). Fifteen giraffes could not survive—there would not be enough food. The carrying capacity of this area is 10 giraffes

12. Communities • Most ecosystems contain more than one type of organism. • All the different populations that live together in an area make up a community. http://www.wrightgroup.com/download/lit/ces_tg_g3_4_samples.pdf

13. Symbiosis • A close relationship between two species that benefits at least one of the species. • The 3 types of symbiosis are: • Mutualism • Commensalism • Parasitism

14. Mutualism • A relationship in which both species benefit. • Example: • Termites and intestinal flagellates • These flagellates live in the gut of termites to digest and convert wood into sugars

15. Commensalism • A relationship in which one species benefits and the other species is neither helped nor harmed. • Example: • Cattle Egret • Perch on top of cows feeding off of the ticks and other insects.

16. Parasitism • Involves one organism living on or inside another organism and harming it. • The organism that benefits is called a parasite, while the organism it lives in or on is called the host. • Example: • Fleas, ticks and leeches • Tapeworms

17. Energy Roles • An organism’s energy role in an ecosystem may be that of a producer, consumer or decomposer.

18. Producer • An organism that can make its own food is a producer. • Many producers make their food through photosynthesis. http://techalive.mtu.edu/meec/module19/images/Photosynthesis.jpg

19. What is the source of energy for this forest? Sunlight What do plants do with the energy? Convert it to food through photosynthesis http://johnmartintaylor.com/images/200203_s_175-111_sch_fb_0011h1.jpg

20. Consumer • An organism that obtains energy by feeding on other organisms is a consumer. • Consumers are classified by what they eat: • Herbivores eat plants • Carnivores eat animals • Omnivores eat both plants and animals • Scavengers are carnivores that feed on dead organisms.

21. http://www.sheppardsoftware.com/content/animals/kidscorner/foodchain/decomposers.gifhttp://www.sheppardsoftware.com/content/animals/kidscorner/foodchain/decomposers.gif

22. Food Chains • A food chain is a flow of energy from one organism to the next and the next and so on… http://www.umaine.edu/umext/earthconnections/images/foodchain.gif

23. Food Webs • A food web consists of the many overlapping food chains in an ecosystem. http://www.cals.ncsu.edu/course/ent425/images/tutorials/ecology/trophic_levels/foodweb.gif

24. Food Webs • Arrows are used to indicate the direction of energy flow. http://king.portlandschools.org/files/houses/y7/animalmaineia/files/species/rdovefi/foodweb/Food_Web3.gif

25. Energy • Ecosystems must constantly be supplied with energy, usually in the form of sunlight. • Energy enters an ecosystem and moves from producers to consumers to decomposers.

26. Nitrogen Cycle • Nitrogen is a necessary building block in the matter that makes up living things. • The air around you is 78% nitrogen gas, however most organisms can not use the nitrogen gas in the air. • Most organisms can use nitrogen only once it has been “fixed” or combined with other elements.

27. Nitrogen Cycle • The process of changing nitrogen gas (in the air) into a usable form is called nitrogen fixation. • Most nitrogen fixation is performed by certain kinds of bacteria.

28. Nitrogen Cycle Nitrogen moves from the air to the soil, into living things, and back into the air. How do consumers obtain nitrogen? By eating nitrogen compounds in plants. www.kidsgeo.com/images/nitrogen-cycle.gif

29. Carbon Cycle • Carbon is the building block for the matter that makes up the bodies of living things. • It is present in the atmosphere in the gas carbon dioxide. • Producers take in carbon from the atmosphere during photosynthesis.

30. Carbon Cycle • Producers use carbon from the carbon dioxide to produce other carbon-containing molecules such as sugars and starches. • Consumers break these molecules down into simpler molecules to obtain energy from them.

31. Carbon Cycle Notice the roles of photosynthesis and respiration in the carbon cycle. http://www.kidsgeo.com/images/carbon-cycle.gif