Go to Section: 3–1What Is Ecology? Pages A.Interactions and Interdependence B.Levels of Organization C.Ecological Methods 1.Observing 2.Experimenting 3.Modeling Section 3-1 Section Outline

Go to Section: 3.1 What Is Ecology? Interactions & Interdependence *Ecology is the study of interactions among organisms and between organisms and their environment *Biosphere- contains the combined portions of the planet in which all of life exists, including land, water and air, or atmosphere; extends 8 kilometers above Earth’s surface to as far as 11 km below the surface of the ocean *Interactions within the biosphere produce a web of interdependence between organisms and the environment in which they live.

Go to Section: Levels of Organization *Some ecologists study interactions between a particular kind of organism and its surroundings. *Species- a group of organisms so similar to one another that they can breed and produce fertile offspring. *Populations- groups of individuals that belong to the same species and live in the same area. *Communities- assemblages of different populations that live together in a defined area *Ecologists may study a particular ecosystem- collection of all the organisms that live in a particular place together with their nonliving environment. *Biomes are groups of ecosystems that have the same climate and similar

Go to Section: dominant communities. *Regardless of the tools they use, scientists conduct modern ecological research using three basic approaches: observing, experimenting, and modeling. *Observing- 1 st step in asking questions *Experimenting- used to test hypotheses; some are conducted in labs, some in natural ecosystems *Modeling- gives insight into complex phenomena such as the effects of global warming on ecosystems

Go to Section: Section 3-1 Figure 3-2 Ecological Levels of Organization

Go to Section: 3–2Energy Flow A.Producers 1.Energy From the Sun 2.Life Without Light B.Consumers C.Feeding Relationships 1.Food Chains 2.Food Webs 3.Trophic Levels D.Ecological Pyramids 1.Energy Pyramid 2.Biomass Pyramid 3.Pyramid of Numbers Section 3-2 Section Outline

Go to Section: Section 2 Energy Flow One of the most important factors that determine whether an ecosystem can sustain life.

Go to Section: 3-2A. Producers Autotrophs – use energy from the environment to make their own food. Sunlight is the main energy source for life on Earth. Chemical energy – Mineral water flowing underground can release energy needed by some organisms.

Go to Section: A-1 Energy from the sun a. Photosynthesis – uses light energy to power chemical reactions that convert CO 2 and H 2 O into oxygen and energy rich carbohydrates such as sugars and starches.

Go to Section: A-1 Continued 2. Land – plants are the main autotrophs Freshwater – algae Wet ecosystems – cyanobacteria

Go to Section: A-2 Life without Light Chemosynthesizers – use chemical energy to produce carbohydrates. (Deep sea vents)

Go to Section: 3-2B. Consumers 1.Obtain energy from other organisms because they cannot produce their own energy. 2.Heterotrophs – organisms that must rely on other organisms for their food and energy supply

Go to Section: Continued…. Types of Heterotrophs: a.Herbivores – eat only plants; cow, deer b.Carnivores – eat only animals; snakes, owls, dogs c.Omnivores – eat both plants and animals; humans, bears, crows

Go to Section: continued d. Detritivores – eat plant and animal remains and other dead matter (detritus); mites, earthworms, snails e. Decomposers – break down organic matter; fungus & bacteria

Go to Section: 3-2C Feeding Relationships Introduction: Energy is a one way path from the sun to autotrophs to heterotrophs 1. Food chains – a series of steps in which organisms transfer energy by eating and being eaten

Go to Section: C-2 Food Webs Show more complex feeding relationships; more realistic Links all food chains in an ecosystem together

Go to Section: Section 3-2 Figure 3-8 A Food Web

Go to Section: C-3 Trophic Levels a.Each step in a food chain or web b.Producers always make up the first trophic level c.Consumers make up the second, third, fourth, etc. d.Each consumer depends on the trophic level before it for energy

Go to Section: 3-2D Ecological Pyramids Introduction: A diagram that shows the relative amount of energy or matter contained within each trophic level in a food chain or food web.

Go to Section: D-1 Energy Pyramid Only about 10% of the energy in the previous tropic level is transferred to the next level. The energy is used for life processes such as growth, reproduction, and movement. (lost as heat) Usually because the organisms are bigger and harder to maintain.

Go to Section: D-2 Biomass Pyramid Biomass – the total amount of living tissue within a given trophic level It represents the amount of potential food available for each trophic level in an ecosystem.

Go to Section: D-3 Pyramid of Numbers Number of individual organisms at each trophic level.

Go to Section: 3–3Cycles of Matter A.Recycling in the Biosphere B.The Water Cycle C.Nutrient Cycles 1.The Carbon Cycle 2.The Nitrogen Cycle 3.The Phosphorus Cycle D.Nutrient Limitation Section 3-3 Section Outline

Go to Section: Condensation Seepage Runoff Precipitation Transpiration Evaporation Root Uptake Section 3-3 The Water Cycle

Go to Section: CO 2 in Atmosphere CO 2 in Ocean Section 3-3 Figure 3-13 The Carbon Cycle

Go to Section: N 2 in Atmosphere NH 3 NO 3 - and NO 2 - Section 3-3 Figure 3-14 The Nitrogen Cycle

Video Click the image to play the video segment. Cycles in Nature

Go to Section: 3.3 Cycles of Matter 1.More than 95% of an organism’s body is made up of oxygen, carbon, hydrogen, and nitrogen *RECYCLING IN THE BIOSPHERE 1.Unlike the one-way flow of energy, matter is recycled within and between ecosystems. 2.Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles. 3.Matter can cycle through the biosphere because biological systems do not use up matter, they transform it. 4.Biogeochemical cycles pass the same molecules around again and again within the biosphere.

Go to Section: The Water Cycle 1.All living things require water to survive. 2.Water molecules enter the atmosphere as water vapor when they evaporate from the ocean or other bodies of water. 3.The process by which water changes from liquid form to an atmospheric gas is called evaporation. 4.Water can also enter the atmosphere by evaporating from the leaves of plants in the process of transpiration. 5.Sun heats atmosphere during the day. 6.As warm air rises, it cools. 7.Water vapor condenses into droplets that form clouds. 8.When droplets become large enough, they return to Earth’s surface in the form of precipitation.

Go to Section: 9. On land, much of the precipitation runs along the surface of the ground until it enters a river or stream that carries runoff back to an ocean or lake.

Go to Section: Nutrient Cycles All the chemical substances that an organism needs to sustain life are its nutrients. Nutrients are needed for: building tissues and carrying out essential life functions Nutrients are passed between organisms and the environment through biogeochemical cycles The Carbon Cycle- carbon is a key ingredient in living tissue- in the form of calcium carbonate, carbon is an important component of animal skeletons and is found in different rocks. CO2 is taken in by plants during photosynthesis and is given off by both plants and animals during respiration 4 main types of processes move carbon through its cycle:

Go to Section: 1.Biological processes, such as photosynthesis, respiration, and decomposition take up and release carbon and oxygen 2.Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans. 3.Mixed biogeochemical processes such as the burial and decomposition of dead organisms and their conversion under pressure into coal and petroleum, store carbon underground. 4.Human activities such as mining, cutting and burning forests, and burning fossil fuels, release carbon dioxide into the atmosphere.

Go to Section: In the atmosphere, carbon is present as CO2. *CO2 is released into the atmosphere by volcanic activity, by respiration, by human activities and by decomposition. Plants take in CO2 and use the carbon to build carbs during photosynthesis. Carbs passed along food webs to animals. In the ocean, carbon is found in the form of calcium carbonate, which is formed by marine organisms. Accumulates as a chalky substance in the bones and shells of organisms. Compounds break down and the carbon returns to the atmosphere.

Go to Section: The Nitrogen Cycle All organisms require nitrogen to make amino acids, which in turn are useful to build proteins N2 makes up 78% of Earth’s atmosphere. NH3 (Ammonia), nitrate ions, and nitrite ions are found in wastes produced by many organisms Plant fertilizers add nitrogen to the biosphere Nitrogen gas is the most abundant form of nitrogen on Earth Only certain bacteria can use this form of nitrogen directly Some bacteria convert nitrogen gas into ammonia by nitrogen fixation When organisms die, decomposers return nitrogen to the soil as ammonia Other soil bacteria convert nitrates into nitrogen gas by

Go to Section: dentrification.

Go to Section: The Phosphorus Cycle 1.Phosphorus- impt in the formation of DNA and RNA 2.Not common in the biosphere 3.Does not enter the biosphere 4.Remains mostly on land in rock and soil minerals 5.Exists as inorganic phosphate 6.As rock and sediment wear, phosphate is released 7.Washes into rivers and streams where it dissolves; some makes its way to the oceans, where it is used by some marine organisms 8.Some phosphate stays on land and cycles between organisms and the soil. 9.When plants absorb phosphate form the soil or from water, the plants bind the phosphate into organic compounds.

Go to Section: Nutrient Limitation 1.Primary Productivity- rate at which organic matter is created by producers; controlled by the amount of available nutrients; limiting nutrient- when an ecosystem is limited by scarce nutrients 2.Fertilizers containing nitrogen, phosphorus, and potassium are added to crops to boost productivity. 3.When an aquatic ecosystem receives a large input of a limiting nutrient, the result is often an immediate increase in the amount of algae and other producers- algal bloom

Section 1 Answers Interest Grabber Answers 1. What living things are found in and around your school? Living things in the school are students, teachers, principal, assistant principals, clerical staff, custodians, lunchroom staff. Students may also include animals in science labs. Living things around the school include grass, trees, shrubs, insects, birds, and so on. 2. What nonliving things are found in your school? The building, furniture, desks, books, papers, and so on 3. Into what large groups are the students in your school divided? 9th, 10th, 11th, 12th grades, or years 4. Into what smaller groups are these large groups divided? Classes 5. Are these groups ever divided into even smaller groups? If so, what are these groups? Students may say that science classes are divided into lab groups; other classes may be divided into groups for projects.

Go to Section: Section 2 Answers Interest Grabber Answers 1.Make a list of five foods that you like to eat. Indicate whether the food comes from a plant (producer) or an animal (consumer). Student lists will be individualized. One possible example would be a hamburger, which comes from a cow or steer. 2.Like many birds, chickens eat grains, which are seeds. Where do seeds come from? Seeds come from plants. 3.Meat comes from beef cattle. What do cattle eat? Cattle eat grass or grains. 4.Construct a diagram showing how one of your favorite foods obtains its energy. Include as many levels as you can. Student diagrams will be individualized based on their food choice. Using the hamburger example, the beef in the hamburger comes from cattle. The cattle feed on grass or grain. Grass or grains are plants, which use energy from the sun to make their own food.

Section 3 Answers Interest Grabber Answers 1.When rain falls on the ground, it either soaks into the soil or runs across the surface of the soil. When rainwater runs across the land, what body of water might collect the rain? Possible answers: a stream, river, pond, or lake 2.From here, where might the water flow? Into a river, and eventually into the ocean 3.After the rain, the sun comes out and the land dries. Where does the water that had been on the land go? It evaporates and becomes a gas in the atmosphere. 4.Construct a diagram that would illustrate all the places a molecule of water might go. Begin with a raindrop and end with a cloud. Student diagrams may include the following: a raindrop —> lawn —> a stream —> river —> large lake —> atmosphere —> cloud.