Presentation on theme: "ECOSYSTEMS AND COMMUNITIES"— Presentation transcript:
1ECOSYSTEMS AND COMMUNITIES CHAPTER 4ECOSYSTEMS AND COMMUNITIES
24-1: THE ROLE OF CLIMATEWeather includes the daily conditions of Earth’s atmosphere at a particular time and placeWeather includes temperature and precipitationClimate involves the average, year after year conditions of temperature and precipitation in a particular regionClimate is caused by the trapping of heat by the atmosphere, latitude, the transport of heat by wind and ocean currents, and the amount of precipitation that results
3WHAT AFFECTS TEMPERATURE? solar energypresence of certain gases in the atmosphere
4THE GREENHOUSE EFFECTThe natural insulating blanket of the biosphere=atmosphereCarbon dioxide, methane, water vapor, and a few other atmospheric gases trap heat energy and maintain Earth’s temperature range
5GREENHOUSE EFFECT CONT. Greenhouse gases allow solar energy to penetrate the atmosphere in the form of sunlightMost sunlight hits the surface of our planet and is converted into heat energy and radiated back into the atmosphereHeat energy is not allowed to pass out of the atmosphere as readily as light energy enters itThe greenhouse gases trap heat inside the earth’s atmosphere
6THE EFFECT OF LATITUDE ON CLIMATE Earth is a sphere tilted on its axis, so solar radiation strikes different parts of Earth’s surface at an angle which varies throughout the year0 degrees latitude=equator=sun is directly overhead at noon all yearmore heat90 degrees latitude=north and south poles=sun is lower in the sky for months at a timeless heatThe difference in heat distribution with latitude has important effects on Earth’s climate zones
7THREE MAIN CLIMATE ZONES Polar zones: cold areas where sun’s rays strike Earth at low angles. Located in areas at the North and South poles, between 66.5 degrees and 90 degrees N and S latitudeTemperate zones: between the polar zones and tropics; climate ranges from hot to cold, depending on the seasonTropical zone (Tropics): near the equator between 23.5 degrees N and S latitude. The tropics receive direct or nearly direct sunlight all year, making the climate almost always warm
8HEAT TRANSPORT IN THE BIOSPHERE Unequal heating of Earth’s surface drives winds and ocean currents, which transport heat throughout the biosphereWinds form because the warm air rises and cool air sinks. Air at the equator rises at the same time, cool air from the poles sinks. The upward movement of warm air and downward movement of cool air creates air currents (wind) that move heat through the atmosphere from regions of sinking air to regions of rising airPrevailing winds bring warm or cold air to a region
9HEAT TRANSPORT CONTINUED Similar patterns of heating and cooling occur in oceansOcean currents transport heat energy within the biosphere; the surface ocean currents warm or cool the air above them, which affects weather and climate of the land massesMountains cause moist air masses to rise, clouds form and precipitation begins on the mountains. Once the air mass reaches the far side of the mountain, it has lost moisture=this is called a rain shadow.Read chapter 4 section 1 in your book and complete chapter 4 section 1 guided reading worksheets!!!!
104-2: WHAT SHAPES AN ECOSYSTEM? Biotic factors are living things within an ecosystem.Examples: trees, birds, plants, bacteriaAbiotic factors are physical, non-living factors that affect an ecosystemExamples: temperature, precipitation***Together, biotic and abiotic factors determine the survival and growth of an organism and the productivity of the ecosystem in which the organism lives.
11SHAPING AN ECOSYSTEM CONTINUED Habitats are areas where organisms liveA niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditionsExample: the type of food the organism eats, how it obtains this food, and which other species use the organism as food
12COMMUNITY INTERACTIONS Competition, predation, and various forms of symbiosis can powerfully affect an ecosystemCompetition occurs when organisms of the same or different species attempts to use an ecological resource in the same place at the same timeResources are necessities for life. Examples include water, nutrients, light, food and space
13Competitive exclusion principle: no two species can occupy the same niche in the same habitat at the same timeDirect competition in nature results in a winner and a loser, where the losing organism fails to survivePredation: when one organism captures and feeds on another organismPredator: organism that does the killingPrey: organism that becomes the food
14SYMBIOSISSymbiosis: any relationship in which two species live closely together
15THREE TYPES OF SYMBIOSIS Mutualism: both species benefit from the relationship. Example: flowers provide insects with food and insects help flowers reproduce by pollinating themCommensalism: one member in the relationship benefits and the other isn’t affected. Example: barnacles attach themselves to whales. The barnacles benefit from the constant movement of water as it carries food particles to them. The whales are not helped nor harmed.
163. Parasitism: one organism lives on or inside another organism and harms it. Example: tapeworms are parasites that live in the intestines of mammals (host). The parasite obtains all or part of its nutritional needs; they weaken the host but rarely kill them
17ECOLOGICAL SUCCESSION Ecosystems and communities are always changing in response to natural and human disturbances.As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.This process is called ecological succession.
18SUCCESSIONPrimary succession: succession on land surfaces where no soil exists. Example: occurs on surfaces formed from volcanic eruptions that have built new islandsNo soil: just ashes and rockPioneer species: first species to populate the area (ex. Lichens, fungi and algae on rock)When pioneer species (lichens) grow, the rock breaks apartLichens die and add organic material to help form soil
19SECONDARY SUCCESSIONSecondary succession occurs when land cleared and plowed for farming is abandoned.Secondary succession also occurs after wildfires burn woodlandsClimax species: mature, stable species that don’t undergo further succession
20SUCCESSION IN MARINE ECOSYSTEMS A whale dies and sinks to the barren ocean floor; the carcass attracts scavengers and decomposers that feast on decaying meat (ex. Sharks)Within a year, most tissue has been eaten and the carcass supports a smaller number of fish, crabs, snails; the decomposition of the whale enriches sediment with nutrients where marine worms begin to liveWhen the skeleton remains, heterotrophic bacteria decompose the oils inside the whale bones which release compounds that serve as energy sources for chemosynthetic autotrophs (ex. Mussels, worms, crabs, clams)***re-read section 4-2 pages in your book and complete the guided reading worksheets***
21CHAPTER 4 SECTION 3: LAND BIOMES A biome is a physical environment that contains characteristic assembly of plants and animalsThe major biomes include:Tropical rain forestTropical dry forestTropical savannaDesertTemperate grasslandTemperate woodlands/shrublandsTemperate deciduous forestNorthwestern coniferous forestBoreal forestArctic tundra
22CLIMATE AND MICROCLIMATE The two main factors that determine climate are temperature and precipitationBoth temp. and precipitation can be summarized on a graph called a climate diagramA microclimate is a climate within a small area that differs significantly from the climate around it (example: San Francisco=certain streets within the city are blanketed with a thick fog, while the sun shines a few blocks away)
23BIOMES CONTINUEDEach biome is defined by a unique set of abiotic factors, particularly climate, and has a characteristic ecological community.Transitional areas between biomes =one biome’s plants and animals gradually become less frequent, while the organism characteristics of the adjacent biome becomes more frequent
24OTHER LAND AREASMountain ranges and polar ice caps do not fall into the major biome categoriesMountain ranges are found on all continents.Abiotic and biotic conditions vary with elevationAs you move up from base of mountain to summit, temperature becomes colder and precipitation increases. Types of plants and animals change as a result.
25***READ PAGES 98-105 AND COMPLETE 4-3 GUIDED READING WORKSHEETS*** Polar ice caps involve the polar regions that border the arctic tundra and are cold year- round***READ PAGES AND COMPLETE 4-3 GUIDED READING WORKSHEETS***
264-4: AQUATIC ECOSYSTEMS 3/4 of earth’s surface is covered in water Water communities include oceans, streams, lakes, and marshes.Water communities are controlled by biotic and a biotic factors including light, nutrient availability and oxygen.
27Aquatic ecosystems are determined primarily by the depth, flow, temperature and chemistry of the overlying water.Aquatic ecosystems are grouped according to the abiotic factors that affect themLand biomes are grouped geographically
28FACTORS AFFECTING AQUATIC ECOSYSTEMS Depth of water: distance from the shore determines the amount of light organisms receiveWater chemistry: amount of dissolved chemicals (salts, nutrients, oxygen) on which life dependsLatitude: aquatic ecosystems in polar, temperate, and tropical oceans all have distinctive characteristics
29FRESHWATER ECOSYSTEMS Two main types: flowing water and standing waterFlowing water ecosystems:rivers, streams, creeks, brooksOrganisms are well adapted to the rate of flowOriginate in mountains or hills from underground sourcesRapid water has a higher amount of distilled water but little plant lifeMoving downhill, sediments build up and plants establish themselvesSlow moving water through flat areas where turtles and river otters make their homes
302. Standing water ecosystems Lakes and pondsWater circulates within them and usually flows in and outCirculation distributes heat, oxygen, and nutrientsPlankton live here: tiny free floating or weakly swimming organisms that live in freshwater and saltwater environmentsPhytoplankton: single celled algae supported by nutrients in water and form the base of aquatic food websZooplankton: planktonic animals that feed on phytoplankton
31FRESHWATER WETLANDSA wetland is an ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the yearA wetland is usually a mixture of salt and freshwaterIt is a breeding ground for insects, fish, amphibians, and migratory birds
32THREE MAIN TYPES OF FRESHWATER WETLANDS Bogs: usually form in depressions called “kettle holes” left by icy sheets that melted thousands of years ago. Sphagnum moss grows here because water is acidic.Marshes: shallow wetlands along rivers. They may be underwater for all or part of a year. Contains cattails and tall, grasslike plantsSwamps: slowly moving water that looks like a flooded forest. Contains trees and shrubs.
33ESTUARIES Wetlands formed where rivers meet the sea Mixture of freshwater and saltwaterAffected by the rise and fall of ocean tidesMost are shallow, so sunlight reaches the bottom to begin photosynthesisPrimary producers are plants, algae and bacteriaMost primary production is NOT consumed by herbivores. Instead, it enters the food web as detritus=tiny pieces of organic material that provide food for organisms at the base of the estuary’s food web (ex. Clams, worms, sponges)
34Salt marshes: temperate zone estuaries dominated by salt tolerant grasses above the low tide line and sea grasses under waterMangrove swamps: coastal wetlands that are widespread across tropical regions. Dominant plants are salt tolerant trees and sea grasses. It is a valuable nursery for fish and shellfish. The largest in the United States is the Florida Everglades National Park
35MARINE ECOSYSTEMSPhotic zone: well lit upper layer where photosynthesis takes place. Depth of 200 meters; where algae and other producers growAphotic zone: permanently dark layer just beneath the photic zone; chemosynthetic autotrophs can survive here
36OCEAN ZONESOcean zones are based on the depth and distance from the shore. They are the intertidal zone, the coastal ocean, and the open ocean.Each zone supports distinct ecological communities
37INTERTIDAL ZONE Regular and extreme changes in surroundings One or two times, the zone is submerged in seawater. The rest of the time, it is exposed to air, sun and temperature changesBattered by waves and strong currents
38ROCKY INTERTIDAL ZONEExists in temperate regions where exposed rocks line the shoreBarnacles and seaweed permanently attach themselves to rocksSnails and sea urchins cling to rocks by their feetZonation=prominent, horizontal banding of organisms that live in a particular habitat. In the rocky intertidal zone, each band can be distinguished by differences in color or shape of the major organisms
39COASTAL OCEANExtends from the low-tide mark to the outer edge of the continental shelf.It is the relatively shallow border that surrounds the continents.Rich in plankton and other organismsExample: kelp forests=giant brown algae that can grow as much as 50 cm a day. It is found in cold, temperate seas around the world. They support a food web of snails, sea otters, fish, seals, and whales
40CORAL REEFSNamed for the coral animals whose hard, calcium carbonate skeletons make up their primary structureMost diverse and productive environments on earthCoral animals=use tentacles to capture and eat microscopic creatures; they cannot grow in cold water or water low in salt. They live in symbiosis with algae.Almost all growth in a coral reef occurs within 40m of the surface
41OPEN OCEANThe oceanic zone begins at the edge of the continental shelf and extends outwardit is the largest marine zone covering more than 90 % of surface area of the world’s oceansOrganisms are exposed to high pressure, frigid temperatures, and total darknessFish of all shapes and sizes dominate the open ocean (swordfish, octopus)Dolphins and whales could live here, but must stay near the surface to breathe
42BENTHIC ZONE The ocean floor Benthos=organisms that live attached to or near the bottom (sea stars, sea anemones, marine worms)The zone extends horizontally along the ocean floor from the coastal ocean through the open oceanBenthic ecosystems depend on food from organisms that grow in the photic zone (producers)They feed on pieces of dead organic material (detritus) that drift downward from the surface of the water
43Chemosynthetic bacteria= support life without light and photosynthesis They live near deep-sea vents where superheated water boils out of cracks on the ocean floor*Read pages in your textbook. Complete guided reading worksheets section 4-4.**Prepare for a test!!!!