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CHAPTER 4. Ecosystems and Communities. 4.1 Climate. Weather vs. Climate Weather Day to day conditions Climate Average conditions over a long period Year to year patterns of temperature and precipitation “Weather is how you pack your suitcase; climate is how you shop for a wardrobe”.
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CHAPTER 4 Ecosystems and Communities
4.1 Climate • Weather vs. Climate • Weather • Day to day conditions • Climate • Average conditions over a long period • Year to year patterns of temperature and precipitation “Weather is how you pack your suitcase; climate is how you shop for a wardrobe”
4.1 Climate • Solar Energy • Some energy is reflected back into space and some is absorbed • Absorbed energy is converted into heat • Some radiates into space • Some is trapped in the biosphere • Greenhouse Effect • Greenhouse Gasses • Carbon dioxide, methane, & water vapor • Allows visible light to enter but traps heat • Different wavelengths Figure 4.1 Page 97
4.1 Climate • Latitude and Solar Energy • Creates 3 different climate zones • Tropical • Temperate • Polar • Depends on amount of direct sunlight • Due to tilt and curvature of Earth Figure 4.2 Page 97
4.2 Niches and Community Interactions • Tolerance • Range of conditions under which it can grow and reproduce • Habitat • The place where a species lives • Determined by the tolerance of the species
4.2 Niches and Community Interactions • Niche • An organisms “role” in the ecosystem • How it interacts with biotic and abiotic factors as it obtains resources • What it needs to survive and reproduce • Food, water, nutrient, space, etc. • Encourages competition
4.2 Niches and Community Interactions • Competitive Exclusion Principle • No two organisms can occupy exactly the same niche in exactly the same habitat at the same time • Competition causes one species to die out or move
4.2 Niches and Community Interactions • Dividing Resources • By causing species to divide resources, competition helps determine the number and kinds of species in a community and the niche each species occupies
4.2 Niches and Community Interactions • Predation • One organism captures and eats another • Predator-prey relationship • Affect the size of prey populations
4.2 Niches and Community Interactions • Herbivory • An animal(herbivore) feeds on a producer(plant) • Affect the size and distribution of plant populations
4.2 Niches and Community Interactions • Keystone Species • Population of a single species can cause dramatic changes in the structure of the community
4.2 Niches and Community Interactions • Symbiosis • Any relationship in which two species live closely together • Three main classes of symbiotic relationships in nature: • Mutualism • Parasitism • Commensalism
4.2 Niches and Community Interactions • Mutualism • Both species benefit from the relationship • Crocodile and Plover
4.2 Niches and Community Interactions • Parasitism • One species benefits and the other is harmed • Leech and human • Parasite does not want to kill host • WHY?
4.2 Niches and Community Interactions • Commensalism • One organism is benefited and the other is neither benefited nor harmed • Barnacle and whale
4.3 Succession • Ecological Succession • Video
4.3 Succession • Ecological Succession • A series of changes that occur in a community over time • Some species die out and some new species move in • Number of species typically increases • Example: Krakatau
4.3 Succession • Primary Succession • Succession that begins in an area with no remnant of an older community • Making of new land or sterilizing existing areas • After volcanic eruptions • Pioneer species • Breakdown rock and add organic material to form soil • Lichens
4.3 Succession • Secondary Succession • Existing communities are not completely destroyed • Proceeds faster because soil survives • Fire, hurricane, logging, farming 3 years 5 years 40+ years
4.3 Succession • Five stages of succession • Stage 1 • Grasses and weeds begin to grow and scatter seeds • Insects, worms, and birds return • Lasts about 2 years • Stage 2 • Dense shrubs, vines and non-woody short plants appear • Rabbits, snakes, and mice move in • Lasts about 5 years
4.3 Succession • Five stages of succession • Stage 3 • Fast growing thin trunk trees take over (birch and popple) • Habitat for squirrels • Larger animals return • Lasts about 15 years • Stage 4 • Diverse species of diverse ages, • From ground cover and undergrowth plants to tall trees • Lasts about 40 years
4.3 Succession • Five stages of succession • Stage 5 • Climax community • Most diverse forest ecosystem
4.4 Biomes • Biomes • Described in terms of abiotic and biotic factors • Abiotic factors • Climate • Soil types • Biotic Factors • Plant life • Animal life
4.5 Aquatic Ecosystems • Water Depth • Photic Zone • Region near the surface where photosynthesis can occur • Aphotic Zone • Dark region below the photic zone where photosynthesis can not occur • Benthic Zone • Rocks and sediments at the bottom of a body of water
4.5 Aquatic Ecosystems • Why are some photic zones much deeper than others?
4.5 Aquatic Ecosystems • Temperature • Colder at poles and warmer near equator • Warmer at surface and colder at greater depths • Currents • Carry nutrients • Affected by water temperatures
4.5 Aquatic Ecosystems • Marine Ecosystems • Ocean zones are divided into zones based on depth and distance from shore • Intertidal Zone • Submerged in high tide and exposed at low tide • Costal Ocean • Brightly lit and well supplied with nutrients • Open ocean • Broken into two regions: • Photic zone • Aphotic zone
4.5 Aquatic Ecosystems Marine Ecosystems
