CHAPTER 3ECOSYSTEMS

By: Landon and Christian

What is Ecology?• Ecology- is a study of connections in nature.• Ecology (from Greek: οἶκος, "house"; -λογία, "study of") is the scientific

study of the relation of living organisms with each other and their surroundings. Ecosystems are defined by a web, community, or network of individuals that arrange into a self-organized and complex systems and several levels of bigger systems constituting systems of smaller systems within them. Ecosystems create biophysical feedback between living (biotic) and nonliving (abiotic) components of an environment that generates and regulates the biogeochemical cycles of the planet. Ecosystems provide goods and services that sustain human societies and general well-being. Ecosystems are sustained by biodiversity within them. Biodiversity is the full-scale of life and its processes, including genes, species and ecosystems forming lineages that integrate into a complex and regenerative spatial arrangement of types, forms, and interactions.

What basic process keep us and other organisms alive?

• Photosynthesis:

• Photosyntheis: is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some algae (Kingdom Protista). Plants need only light energy, CO2, and H2O to make sugar. The process of photosynthesis takes place in the chloroplasts, specifically using chlorophyll, the green pigment involved in photosynthesis. Photosynthesis takes place primarily in plant leaves, and little to none occurs in stems, etc. The parts of a typical leaf include the upper and lower epidermis, the mesophyll, the vascular bundle(s) (veins), and the stomates. The upper and lower epidermal cells do not have chloroplasts, thus photosynthesis does not occur there. They serve primarily as protection for the rest of the leaf. The stomates are holes which occur primarily in the lower epidermis and are for air exchange: they let CO2 in and O2 out. The vascular bundles or veins in a leaf are part of the plant's transportation system, moving water and nutrients around the plant as needed. The mesophyll cells have chloroplasts and this is where photosynthesis occurs.

Food chain

• Food Chain: A food chain is the sequence of who eats whom in a biological community (an ecosystem) to obtain nutrition. A food chain starts with the primary energy source, usually the sun or boiling-hot deep sea vents. The next link in the chain is an organism that make its own food from the primary energy source -- an example is photosynthetic plants that make their own food from sunlight (using a process called photosynthesis) and chemosynthetic bacteria that make their food energy from chemicals in hydrothermal vents. These are called autotrophs or primary producers.

• Next come organisms that eat the autotrophs; these organisms are called herbivores or primary consumers -- an example is a rabbit that eats grass.

• The next link in the chain is animals that eat herbivores - these are called secondary consumers -- an example is a snake that eat rabbits.

• In turn, these animals are eaten by larger predators -- an example is an owl that eats snakes.

• The tertiary consumers are are eaten by quaternary consumers -- an example is a hawk that eats owls. Each food chain end with a top predator, and animal with no natural enemies (like an alligator, hawk, or polar bear).

• The arrows in a food chain show the flow of energy, from the sun or hydrothermal vent to a top predator. As the energy flows from organism to organism, energy is lost at each step. A network of many food chains is called a food web.

• Trophic Levels:The trophic level of an organism is the position it holds in a food chain.

Food Web• Food web: A food web is a

graphical description of feeding relationships among species in an ecological community, that is, of who eats whom It is also a means of showing how energy and materials flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called "links", and the species are sometimes referred to as "nodes" in food web diagrams.

Water cycle• The earth has a limited

amount of water. That water keeps going around and around and around and around and (well, you get the idea) in what we call the "Water Cycle". This cycle is made up of a few main parts:

• evaporation (and transpiration)

• condensation• precipitation• collection

• Evaporation: Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air.

• Condensation: Water vapor in the air gets cold and changes back into liquid, forming clouds. This is called condensation.

• You can see the same sort of thing at home... pour a glass of cold water on a hot day and watch what happens. Water forms on the outside of the glass. That water didn't somehow leak through the glass! It actually came from the air. Water vapor in the warm air, turns back into liquid when it touches the cold glass.

• Precipitation: Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow

Carbon cycle• The Carbon Cycle is a complex series of

processes through which all of the carbon atoms in existence rotate. The same carbon atoms in your body today have been used in countless other molecules since time began. The wood burned just a few decades ago could have produced carbon dioxide which through photosynthesis became part of a plant. When you eat that plant, the same carbon from the wood which was burnt can become part of you. The carbon cycle is the great natural recycler of carbon atoms. Unfortunately, the extent of its importance is rarely stressed enough. Without the proper functioning of the carbon cycle, every aspect of life could be changed dramatically.

Nitrogen cycle• Plants need nitrogen to grow, develop and

produce seed. The main source of nitrogen in soils is from organic matter. Soils in Missouri commonly contain one to four percent organic matter. Organic matter largely arises from plant and animal residues. The nitrogen in organic matter is largely in organic forms that plants cannot use. Bacteria found in soils convert organic forms of nitrogen to inorganic forms that the plant can use. Nitrogen is taken up by plant roots and combined into organic substances in the plant, such as enzymes, proteins and chlorophyll. Chlorophyll gives the plant its green color. When the plant dies, it decays and becomes part of the organic matter pool in the soil. The basic nitrogen cycle is illustrated in. It shows nitrogen changing from organic matter in the soil, to bacteria, to plants and back to organic matter.

Sulfur Cycle• Sulphur is one of the components that

make up proteins and vitamins. Proteins consist of amino acids that contain sulphur atoms. Sulphur is important for the functioning of proteins and enzymes in plants, and in animals that depend upon plants for sulphur. Plants absorb sulphur when it is dissolved in water. Animals consume these plants, so that they take up enough sulphur to maintain their health.

Major components of an ecosystem

• An ecosystem consists of the biological community that occurs in some locale, and the physical and chemical factors that make up its non-living or abiotic environment. There are many examples of ecosystems -- a pond, a forest, an estuary, a grassland. The boundaries are not fixed in any objective way, although sometimes they seem obvious, as with the shoreline of a small pond. Usually the boundaries of an ecosystem are chosen for practical reasons having to do with the goals of the particular study. The study of ecosystems mainly consists of the study of certain processes that link the living, or biotic, components to the non-living, or abiotic, components. Energy transformations and biogeochemical cycling are the main processes that comprise the field of ecosystem ecology. As we learned earlier, ecology generally is defined as the interactions of organisms with one another and with the environment in which they occur. We can study ecology at the level of the individual, the population, the community, and the ecosystem.

• Studies of individuals are concerned mostly about physiology, reproduction, development or behavior, and studies of populations usually focus on the habitat and resource needs of individual species, their group behaviors, population growth, and what limits their abundance or causes extinction. Studies of communities examine how populations of many species interact with one another, such as predators and their prey, or competitors that share common needs or resources.

• In ecosystem ecology we put all of this together and, insofar as we can, we try to understand how the system operates as a whole. This means that, rather than worrying mainly about particular species, we try to focus on major functional aspects of the system. These functional aspects include such things as the amount of energy that is produced by photosynthesis, how energy or materials flow along the many steps in a food chain, or what controls the rate of decomposition of materials or the rate at which nutrients are recycled in the system

Chapter 3 Vocab1. Anaerobic respiration- form of cellular reparation in which

some decomposers get energy they need through the breakdown of glucose in absense of oxygen

2. Aquatic life zones- Marine and freshwater portions of the biosphere

3. Autotrophs- organisms that use solar energy or chemical the organic compounds it needs

4. Biomass – organic matter produced by plants and other photosynthetic producers

5. Biomes- terrestrial regions inhabited by certain types of life, especially vegetation

6. Biosphere- zone of earth where life is found7. Carnivores- animal that feeds on other animals

8.Chemosynthetic – process in which certain organisms extract inorganic coumpunds from their environment and convert them into organic nutriets compunds without the

presence of sunlight9. community- populations of all species living and

interacting in an area at a particular time10. Cosumers- organisms that cannot synthesize the

organic nutrients it needs and gets its organic nutrients by feeding on the tissues of producers or other consumers11. Decomposers- organisms that digest parts of dead organisms and cast off fragments and wastes of living

organisms by breaking down molecules12. detrivors- consumer organisms that feed off parts of

dead organisms13.Ecological efficiency- percentages of energy tansferred from one trophic level to another in a food chain or web

14. ecology- biological science that studies the relationships between living organisms and their

environment15. ecosystem- community of different species

interacting with one another and with the chemical and physical factors making up its nonliving

environment16. fermentation- decomposers get energy from breakdown of glucose in the absence of oxygen

17. Food chain- series of organisms in which each eats or decomposes the preceding one

18. Food web- complex network of many interconnected food chain and feeding relationships

19. Gaia hypothesis-

20. Gross primary productivity- rate at which an ecosystems producers capture and store a given amount of chemical energy as biomass in a given length of time

21. herbivores- plant eating organisms22. humus- slightly soluble residue of undigested or

partially decomposed organic materials in topsoil23. Lydrosphere- earths liquid water and water vapor in

the atmosphere24. Infiltration- downward movement of water through

soil25. leaching- process in which various chemicals in upper

layers of soil are dissolved and carried to lower layers26. Limiting factor- single factor that limits the growth,

abundance, or distrubution of the population of a species in an ecosystem

27. lithosphere- outer shell of the earth, composed of the crust and the rigid , outermost part of the mantle

outside the asthenosphere28. natural greenhouse effect- heat buildup in the

troposphere because of the presence of greenhouse gases

29. nutrients (biogeochemical) cycles- natural process that recylces nutrients in various chemical forms from

the nonliving environment to living organisms and then back to the non living

30. nutrients- any food or element an organism must take in to live grow or reproduce

31. omnivores- animals that can use both plants and other animals as food sources

32. Population- group of individual organisms of the same species living in a particular area

33. Pyramid of energy flow- diagram representing the flow of energy through each trophic level in a

food chain or food web34. Range of tolerance- range of chemical and

physical conditions that must be maintained for populations of particular species to function

35. soil- complex mixture of inorganic minerals decaying organic matter, water, air, and living

organisms36. Soil horizons- horizontal zones that make up a

particular mature soil37. Soil profile- cross sectional ciew of the horizons

of soil38. Soil texture- determined by the relative amonts of the different seizes and types of mineral particles

39. species- group of organisms that resemble one another in appearance, behavior, chemical makeup and processes, and genetic structure

40. stratosphere- second layer of the atmosphere, contains small amounts of gaseous ozone.

41. Tropic level- all organisms that are the same number of energy transfers away from the

original source of energy that enters an ecosystem

42. troposphere- Inner most layer of the atmosphere and contains 75% of the mass of the

earths air