Unit 6: Ecosystems

1. Unit 6: Ecosystems

2. An Ecosystem is… • All the living and nonliving things that interact in a particular environment • E.x.: mountain streams, deep oceans, dense forests, and flat plains

3. Habitats • An organism obtains food, water, shelter, and other things it needs to live, grow, and reproduce from its surroundings. • The place where an organism lives and that provides the things the organism needs is called its habitat. • In a given ecosystem there may be many different habitats.

4. Factors • Biotic factors – the living parts of an ecosystem. • Includes: • Grass and plants • Other animals • Decomposers (like bacteria)

5. Factors (2) • Abiotic factors – the nonliving parts of an ecosystem • Include: • Water • Sunlight • Oxygen • Temperature • Soil

6. Check your knowledge - • How are biotic factors different from abiotic factors?

7. Ecological Organization Organism Population Community Ecosystem

8. Ecological Organization • All the members of one species in a particular area is a population • All the different populations that live together in an area make up a community • The smallest unit of organization is a single organism, which belongs to a population of other members of its species. The population belongs to a community of different species. The community and abiotic factors together form an ecosystem.

9. Population • All the members of a species in an area • Can change in size when members enter or leave the population. • Commonly by birth or death • Immigration: moving into a population • Emigration: leaving (exiting) a population

10. Limiting Factors • Environmental factor that prevents a population from increasing • Include: • Food • Carrying capacity: the largest population an environment can support • Space • Weather

11. Interactions • Every organism has a variety of adaptations that are suited to its specific living conditions • Niche: organism’s role or how it makes its living • 3 main types of interactions: • Competition • Predation • Symbiosis

12. Symbiosis • Close relationship between 2 species that benefit at least 1 of the species • 3 types: • Mutualism: when both species benefit Ex. Bacteria in your intestines • Commensalism: when 1 species benefits and the other is not helped or harmed Ex: Birds in a tree • Parasitism: when 1 species lives in or on another and harms it Ex: Fleas on a dog

13. Energy Flow in Ecosystems • Organisms have their own role in the flow of energy in an ecosystem • An organism’s energy role in an ecosystem may be: • Producer • Consumer • Decomposer

14. Producer • An organism that can make its own food • Plants, algae, and bacteria

15. Consumer • An organisms that obtains energy by feeding on other organisms • Classified by what they eat: • Herbivore: only eat plants • Carnivore: only eat animals (meat) • Omnivore: eat plants and animals • Scavenger: carnivore that feeds on bodies of dead organisms

16. Decomposer • An organisms that breaks down waste and dead organisms • Bacteria and fungi • Mold & mushrooms

17. Food Chain • Series of events in which one organism eats another and obtains energy. • Producer • First-level (primary) consumer • Second-level (secondary) consumer • Third-level (tertiary) consumer • Decomposer

18. Food Web • The many overlapping food chains in an ecosystem • Pg. 50 in your book • Note: an organism may play more than one role in an ecosystem

19. Energy Pyramid • Shows the amount of energy that moves from one feeding level to another in a food web. • The most energy is available at the producer level. At each level in the pyramid, there is less available energy than at the level below. • Pg. 52 in book

20. Ecological Organization Tertiary consumer 1kcal Secondary consumer 10 kcal Primary consumer 100 kcal Producer 1000 kcal

21. Cycles of Matter • Pg. 53-57 in book • Since energy cannot be recycled, it must continuously be supplied • Energy is transferred from the sun, to producer, consumer, and decomposer

22. Carbon and oxygen cycles • Remember: carbon is present in all living things • Producers take in CO2 from the atmosphere during photosynthesis • Producers use C from the CO2 to produce carbon-containing molecules (sugars & starches) • Consumers break these molecules down to obtain energy • Oxygen is also cycling through the ecosystem

24. Nitrogen cycle • Most organisms cannot use the nitrogen gas in the air; they can only use it when it is “fixed”, combined with other elements • Nitrogen moves from the air, to the soil, into living things, and back into the air

26. Nitrogen fixation • Conducted by types of bacteria • Mutualistic relationship between the plant (usually legumes) and the bacteria

27. Nitrogen return • Used to build proteins and other substances • Decomposers break down nitrogen in animal waste and dead organisms • Returns nitrogen to soil • Bacteria return some N as free-nitrogen in air

28. Biomes • Group of ecosystems with similar climates and organisms • Climate conditions: • temperature and rainfall in an area that determine its biome • Climate limits types of plants, and plants limit types of animals

29. Rainforest biomes • Tropical rain forests • Warm, wet (lots of rain) regions close to the equator • Many types of trees • Largest variety of plants and animals of any biome • Canopy (tallest trees) • Understorty (below the canopy) • Forest floor (very dark) • Largest variety of plants and animals of any biome

30. Rainforest biomes • Temperate rain forests • Has moderate temperatures • Northwestern U.S. • Large trees (redwoods and Douglas firs) • Heavy precipitation

31. Desert biomes • An area that receives less than 25 cm of rain per year • Undergo large shifts in temperature • Organisms are adapted to the lack of rain • Most animals are active at night when temperatures are cooler

32. Grassland biomes • Also called prairies or savannahs (receive more rain) • Receives more rain than deserts, but not enough for many trees to grow (about 25-75cm of rain per year) • Home to many large animals • Herbivores: bison, antelope, zebra, rhino, giraffe, & kangaroo

33. Deciduous Forest biomes • Full of trees who shed their leaves and grow new ones each year • Ex: oak & maple trees • Receive enough rain to support tree growth (at least 50cm per year) • Temperatures vary throughout the year • Home to many different species, although some migrate or hibernate during winter months

34. Boreal forest biomes • Full of coniferous trees (gymnosperms: fir & spruce trees) • Colder weather • AKA the taiga (TY guh) • Has lots of snow in the winter and rainy summers • Animals include: • Squirrels, insects, birds, deer, elk, moose, wolves, bears, and wolverines

35. Tundra biomes • Extremely cold & dry • Most soil is frozen year round (permafrost) • Plants include: • Shrubs, grasses, and moss • Animals include: • Insects (especially during summer), birds, caribou, foxes, wolves • Sun shines all day during summer in some places and never shines at all during some winter months

36. Freshwater biomes • Affected by: temperature, sunlight, oxygen, and salt content *Sunlight is very important because water absorbs sunlight, therefore there is only enough light for photosynthesis near the surface or in shallow water • Include: • Ponds, lakes, streams, & rivers • Ponds and lakes are bodies of standing fresh water • Organisms: algae, insects, snails, frogs, catfish, bacteria • Streams and rivers are bodies of flowing fresh water • Organisms: trout, insects, and frogs

37. Marine biomes • Water contains salt in varying amounts • Include: • Estuaries – where fresh water and salt water meet • Intertidal zone – part of shore b/w high-tide and low-tide • Neritic zone – shallow water below low-tide zone • Surface zone – all open-ocean zones (algae) • Deep zone – most water is completely dark

38. Mountains and Ice • Don’t fit into any land biome category • Climate conditions change on mountains depending on the altitude • Ice covers some parts of the world • Greenland • Antarctica • Animal species include: • Penguins, polar bears, and seals