1. Ch. 4: Ecosystem and Communties

2. Ch. 4 Outline 4-1: The Role of Climate –What is Climate? –The Greenhouse Effect –The Effect of Latitude on Climate 4-2: What Shapes an Ecosystem –Biotic and Abiotic Factors –The Niche –Community Interactions –Ecological Succession

3. Ch. 4 Outline 4-3: Biomes –The Major Biomes –Other Land Area 4-4: Aquatic Ecosystem –Freshwater Ecosystems –Estuaries –Marine Ecosystems

4. What is Climate? Weather: the day-to-day condition of the Earth’s atmosphere at a particular time and place Climate : the average, year-after-year conditions and temperature and precipitation in a particular region –Caused by many factors including latitude, wind currents, ocean currents, etc. The energy of incoming sunlight drives Earth’s weather and helps determine climate.

5. The Greenhouse Effect Temperature on Earth remain in a suitable range for life because of the atmosphere. –Carbon dioxide, methane, water vapor and a few other atmospheric gases trap heat energy and maintain the Earth’s temperature range.

6. Greenhouse Effect Greenhouse effect : the natural situation in which heat is retained by the layer of gases around Earth –Gases in the atmosphere allow solar energy in but do not allow it to pass out as easily (after it bounces off the Earth and heads in the other direction). This is how heat is trapped inside the Earth’s Atmosphere.

7. Greenhouse Effect Sunlight Some heat escapes into space Greenhouse gases trap some heat Atmosphere Earth’s surface Greenhouse Effect

8. The Effect of Latitude on Climate Earth is tilted on its axis. As a result, sunlight hits the Earth at different angles. –Ex. In the tropics (around the equator), sunlight hits directly year round. Because of this, earth has three different climate zones: polar, temperate, and tropical.

9. The Effect of Latitude on Climate Polar zone : cold areas where the sun’s rays strike the Earth at a low angle. –Around North and South Poles Temperate zones : located between polar zone and tropics –Climates ranges in these zones depending on the season Tropical zone : near the equator –Receive direct sunlight year around.

10. The Effect of Latitude on Climate Sunlight Most direct sunlight Sunlight 90°N North Pole 66.5°N 23.5°N 0° 23.5°S 66.5°S 90°S South Pole Arctic circle Tropic of Cancer Equator Tropic of Capricorn Arctic circle Different Latitudes

11. Heat Transport in the Biosphere The unequal heating of Earth’s surfaces drives wind and ocean currents Warm air tends to rise and cool air sinks. Warm air above the equator rises and cool air from the poles sinks. As a result, air currents (winds) form. –A similar pattern occurs in the oceans Winds and Ocean currents transport heat

12. Biotic and Abiotic Factors Ecosystems are influenced by a combination of biological (living) and physical (nonliving) factors. Biotic Factors : biological influences on an ecosystem Abiotic Factors : physical or non- living factors –Ex. Temperature, humidity, wind, soil, etc…

13. Biotic and Abiotic Factors These types of factors together determine the survival and growth of an organism and the productivity of the ecosystem Habitat : the area in which an organism lives –Includes both abiotic and biotic factors

14. Biotic and Abiotic Factors Biotic Factors ECOSYSTEM Abiotic Factors

15. Community Interaction When organisms live together in a community, they constantly interact. These interactions (such as predation, competition, and symbiosis) greatly affect an ecosystem.

16. Community Interactions Competition: –Occurs when organisms try to use the same resources at the same time and place – Resource : any necessity of life (ex. Food) – Competitive exclusion principle : no two organism can occupy the same niche in the same habitat One will always have a reproductive advantage over the other (even if very small) and will “win” over the other  survive and pass on their genes!!!

17. Community Interaction Predation – Predation : an interaction in which one organism captures and feeds on another organism –Predator vs. Prey Symbiosis: – Symbiosis : any relationship in which two species live closely together –3 main classes of symbiotic relationships: 1.Mutualism : Both Species benefit Ex. Mycorrhizae 2.Commensalism : One benefits, the other is neither helped nor harmed 3.Parasitism : one benefits, the other is harmed Ex. Tapeworms in mammal intestine.

18. Ecological Succession Ecosystems are always changing. They change in response to natural and human disturbances. Older inhabitants gradually die out and new organisms move in, causing even further change. Ecological succession : a series of predictable changes that occurs in a community over time.

19. Ecological Succession Two types of succession: 1.Primary succession : Succession that occurs where no soil exists –Ex. After a volcano Erupts – Pioneer species – first species to populate the area (often lichens) 2.Secondary Succession : occurs when changes happen without removing the soil. –Ex. When a forest is cleared for farming.

20. Biomes Biome : a complex of terrestrial communities that covers a large area and is characterized by certain soil and climate conditions and particular groups of plants and animals Plants and animals have specific adaptations to help them survive in a particular biome. – Ex. Leaves of cacti are small to prevent water loss.

21. The Major Biomes Tropical Rain Forest Tropical Dry Forest Tropical Savanna Desert Temperate Grassland Temperate Woodland and Shrubland Temperate Forest Coniferous Forest Boreal Forest Tundra All of these biomes are characterized by a unique set of abiotic factors (mostly climate) and groups of plants and animals.

22. The Major Biomes Ten Major Biomes BiomePrecipitationTemperatureSoilDiversityTreesGrasses Tropical Rain Foresthighhotpoorhighdensesparse Tropical Dry Forestvariablemildrichmoderatemedium Tropical Savannavariablemildclaymoderatesparsedense Desertlowvariablepoormoderatesparse Temperate Grassland moderatesummer hotrichmoderateabsentdense Temperate woodland and Shrubland summer low, winter moderate summer hotpoorlowmedium Temperate Forestmoderatesummer moderate, winter cold richhighdensesparse Northwestern Coniferous Forest highsummer mild, winter cold rocky, acidiclowdensesparse Boreal Forestmoderatesummer mild, winter cool poor, acidicmoderatedensesparse Tundralowsummer mild, winter cold poorlowabsentmedium

23. World’s Major Biomes Tropical rain forest Tropical dry forest Tropical savanna Temperate woodland and shrubland Desert Temperate grassland Boreal forest (Taiga) Northwestern coniferous forest Temperate forest Mountains and ice caps Tundra

24. Other Land Areas Some areas of Earth do not fall neatly into a major biome category –Ex. Mountain Ranges and Polar Ice Caps Mountain ranges: –On mountains, abiotic and biotic conditions vary with elevation Polar Ice Caps: –Cold and Icy all year round –Dominant life includes penguins and other marine mammals (in Antarctica) and polar bears and insects (North Pole)

25. Aquatic Ecosystems Almost ¾ of the Earth is covered in Water. Aquatic ecosystems are determined primarily by the depth, flow, temperature, and chemistry of the overlying water. Aquatic biomes are mostly grouped by the abiotic factors that affect them, rather then geography.

26. Freshwater Ecosystems Only 3% of the surface water on Earth is Fresh water. Types of Freshwater ecosystems: –Flowing-water Ecosystems Rivers, Streams, creeks Organisms there have adapted to the rate of flow –Ex. Anchoring Structures

27. Freshwater Ecosystem Standing Water Ecosystems –Lakes and ponds –Water circulates within them to distribute nutrients –Provide habitats for plankton : tiny, free-floating organisms Ex. Phytoplankton – type of algae Ex. Zooplankton – animals that feed on phytoplankton

28. Freshwater Ecosystems Freshwater Wetlands – Wetland : Ecosystem in which water covers the soil (or at least near the surface of soil) for part of the year. –Water may be standing or flowing –Freshwater or saltwater (brackish) –Common breeding ground for many animals –Three types: bogs, marshes, swamps

29. Freshwater Ecosystem Duck Dragonfly Phytoplankton Frog Water lilies Mosquito larvae Snail Diving beetle Trout Pickerel Duckweed Snail Benthic crustaceans Hydra Frogs lay eggs in the shallow water near shore.The eggs hatch in the water as tadpoles and move to the land as adults. The shore is lined with grasses that provide shelter and nesting places for birds and other organisms. The roots of water lilies cling to the pond bottom, while their leaves, on long flexible stems, float on the surface. The bottom of the pond is inhabited by decomposers and other organisms that feed on particles drifting down from the surface. Fish share the pond with turtles and other animals. Many of them feed on insects at the water’s edge. Plankton and the organisms that feed on them live near the surface where there is enough sunlight for photosynthesis. Microscopic algae are among the most important producers. Crayfish Spoonbill

30. Estuaries Estuaries : Wetlands formed where rivers meet the sea They contain a mixture of fresh and salt water. Most are shallow so sunlight reaches the bottom (photosynthesis can happen there!)

31. Estuaries Primary producers there: Plants, algae, bacteria Most organic matter is not consumed by herbivores, but enters the food web as detritus – Detritus : tiny pieces of organic material Clams, worms, and sponges all feed on detritus. Estuaries support a large amount of biomass. Many fish are born there. Other animals feed and grow in estuaries, where they head out to sea to mature but return to reproduce.

32. Estuaries Salt Marshes : Temperate-zone estuaries dominated by salt-tolerant grasses and seagrasses underwater. –Found on East Coast of North America. Mangrove swamps: found in tropical regions, have salt-tolerant trees called mangroves –Ex. Florida’s Everglades National Park

33. Marine Ecosystems Photic zone : Upper layer of water where photosynthesis can occur Aphotic zone: no light penetrates the water In addition to the division between the photic and aphotic zone, scientists divide the ocean into zones based on the depth and distance from shore – Intertidal zone – Coastal Ocean – Open Ocean Benthic zone: covers ocean floor

34. Zones of the Marine Ecosystem land Coastal ocean Open ocean Ocean trench Aphotic zone Photic zone Continental shelf Continental slope and continental rise Abyssal plain 200m 1000m 4000m 6000m 10,000m

35. Marine Ecosystem Intertidal Zone –Organisms that live here are exposed to many changes in their surroundings. Competition often leads to zonation. Zonation : the horizontal banding of organisms that live in a particular habitat

36. Marine Ecosystem Coastal Ocean –Extends from the low-tide mark to the outer edge of the continental shelf (the shallow border that surrounds the continents). –Most of the coastal oceans fall in the photic zone so it is rich in many organisms –In tropical coastal oceans, coral reefs exist

37. Marine Ecosystem Open Ocean –Begins at the edge of the continental shelf and extends outward. It covers more than 90% of the surface area of the world’s oceans. –Productivity here is low because there are low levels of nutrients deep in the ocean. Fish dominate the open ocean.

38. Benthic Zone The Ocean Floor Benthos : Organisms that live attached to or near the ocean floor – Ex. Sea Stars Depends on food from organisms that grow in the photic zone. Detritus that rains down to the floor.