Chapter 3 The Biosphere 3 1 What Is

Chapter 3 The Biosphere

3. 1 What Is Ecology Biosphere Consists of all of the life on earth and parts of the Earth where life exists • Land, water, and atmosphere • Bacteria underground to spores in the atmosphere • From 8 km above the Earth to 11 km below surface of the ocean

3. 1 What Is Ecology Scientific study of interactions among organisms and between organisms and their physical environment Relationships Eaten plants and animals Competition • Food • Habitat – Rainforest Pollution

3. 1 What Is Ecology Levels of Organization Individual organism Population Community Ecosystem Biome Biosphere

3. 1 What Is Ecology FIGURE 3. 1 on page 65

3. 1 What Is Ecology Biotic Factor Any living part of the environment that an organism might interact with • Animals, plants, bacteria Abiotic Factor Any nonliving part of the environment • Sunlight, heat, precipitation

3. 1 What Is Ecology

3. 1 What Is Ecology List biotic and abiotic factors

3. 2 Energy, Producers, and Consumers Primary Producers Living systems operate by expending energy • Growth, reproduction, and metabolic processes NO organism can make its own energy • Sunlight is the ultimate source of energy for most life on earth • For some organisms, chemical energy stored in inorganic compounds serves as the ultimate energy source

3. 2 Energy, Producers, and Consumers Autotrophs Use solar or chemical energy to produce food • Assembling inorganic compounds into complex organic molecules Store energy in forms that make it available to other organisms that eat them “PRIMARY PRODUCERS”

3. 2 Energy, Producers, and Consumers Energy From the Sun Photosynthesis • Captures light energy and uses it to power chemical reactions – Converts CO 2 and H 2 O into O 2 and energy rich carbohydrates – Makes Sugars and Starches – Removes CO 2 from the atmosphere and adds O 2

3. 2 Energy, Producers, and Consumers Photosynthesis

3. 2 Energy, Producers, and Consumers Life Without Light Chemosynthesis • Producers harness chemical energy from inorganic materials – Hydrogen sulfide • Uses this chemical energy to produce carbohydrates

3. 2 Energy, Producers, and Consumers Chemosynthesis

3. 2 Energy, Producers, and Consumers Heterotrophs Must acquire energy from other organisms • By ingesting them in one way or another Can not make own food Called consumers

3. 2 Energy, Producers, and Consumers Types of Consumers Carnivores Herbivores Omnivores Scavengers Decomposers Detritivores

3. 2 Energy, Producers, and Consumers FIGURE 3. 6 Page 71

3. 2 Energy, Producers, and Consumers

3. 3 Energy Flow in Ecosystems Food Chain Energy flows in a one way stream • From primary producer to various consumers Series of steps in which organisms transfer energy by eating and being eaten

3. 3 Energy Flow in Ecosystems Food Web Network of all feeding interactions In most ecosystems, feeding relationships are much more complex

3. 3 Energy Flow in Ecosystems Trophic Levels Each step in the food chain or food web Primary producers always make up the first trophic level Each step is further removed from the primary producer

3. 3 Energy Flow in Ecosystems Making a Food Web Primary producers are on the bottom and carnivores are on the top following trophic levels Arrows point in direction of energy flow

3. 3 Energy Flow in Ecosystems Pyramid of Energy Shows the relative amount of energy available at each trophic level Organisms expend much of their energy • Respiration, movement, growth, and reproduction Most of remaining energy is lost as heat Very little is stored • Only about 10% is passed on

3. 3 Energy Flow in Ecosystems Why are food chains usually short?

3. 3 Energy Flow in Ecosystems

3. 3 Energy Flow in Ecosystems Pyramid of Biomass and Numbers Pyramids of biomass show the total amount of living tissue at each trophic level A pyramid of numbers shows the relative numbers of organisms at different trophic levels

3. 4 Cycles of Matter Energy Passes through an ecosystem Gets use or released as heat Matter Cycles through an ecosystem Constantly getting reused

3. 4 Cycles of Matter Water cycle Water moves between the ocean, the atmosphere, and land. • Evaporation & Transpiration • Condensation • Precipitation

3. 4 Cycles of Matter Carbon Cycle Carbon is a key ingredient of all organic compounds Adds CO 2 • Burning • Respiration • Geologic activity Removes CO 2 • Photosynthesis • Dissolves in rainwater

3. 4 Cycles of Matter Nitrogen Cycle Nitrogen is needed by all organisms to build proteins • Nitrogen fixation – Converts nitrogen gas to ammonia • Denitrification – Converts nitrates to nitrogen gas • Primary producers use nitrogen to make proteins and nucleic acid • Consumers eat producers and reuse nitrogen to make own compounds • Decomposers release nitrogen back to soil • Fertilizers add extra nitrogen to soil

3. 4 Cycles of Matter Phosphorus Cycle Phosphorus is needed for molecules such as DNA and RNA • Cycles among land, ocean, and organisms • Does not enter the atmosphere in significant amounts • Fertilizers add extra phosphorus to soil