Chapter Three Review

1. Chapter Three Review Audra Miller & Christina Geissman

2. Vocabulary Anaerobic Respiration: a form of cellular respiration involving the breaking down of glucose, also called fermentation Aquatic Life Zones: divisions of the watery parts of the biosphere Autotrophs:organisms that make their own food, also called producers Biomass: dry weight of all organic matter contained in organisms Biomes: large sections of the biosphere with distance climates and specific species adapted to them Biosphere: all the earth’s ecosystems together

3. Carnivores: meat eaters Chemosynthesis: the process of converting simple inorganic compounds into more complex nutrient compounds without sunlight Community: consists of all the populations of a different species that live and interact in a particular area Consumers: get nutrients by eating something else; cannot make them Decomposers: specialized organisms that recycle nutrients in ecosystems Ecological Efficiency: the percent of usable energy from one trophic level to another

4. Ecology: the study of how organisms react with their environments and each other Ecosystem: a community where populations of different species interact with each other and their environment Fermentation: the same as anaerobic respiration Food Chain: a sequence of organisms in which each organism is food for the next Food Web: many interconnected food chains

5. Gaia Hypothesis: earth behaves like a single self-regulating system Gross Primary Productivity (GPP):the rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass Herbivores: plant eaters Humus: partially decomposed bodies of dead plants and animals Hydrosphere: consists of the world’s water Infiltration: the downward movement of water through soil Leaching: when water in soil dissolves various organic matter in upper layers and carries them down to lower layers of the soil

6. Limiting Factor: one factor more important in regulating population growth than any other Lithosphere: the earth’s crust and upper mantle Natural Greenhouse Effect: as radiation interacts with molecules in the air, it increases kinetic energy, helping warm the troposphere and the earth’s surface Nutrient (Biogeochemical) Cycles: when nutrients move in cycles through air, water, soil, rock, and living organisms

7. Nutrients: the elements and compounds that organisms need to live, grow, and reproduce Omnivores: organisms that live off both plants and animals Population: a group of interacting individuals of the same species in a specific place Pyramid of Energy Flow: illustrates the loss of energy through the food chain Range of Tolerance: the physical and chemical variations in an environment Soil: thin covering over most land

8. Soil Horizons: horizontal layers of mature soil Soil Profile: a cross-sectional view of soil horizons Soil Texture: relative amounts of different sizes of minerals found in soil Species: groups of organisms which resemble one another in appearance, behavior, chemistry, and genetic makeup Stratosphere: the layer above the troposphere, the layer with gaseous ozone which filters incoming ultraviolet radiation Trophic Level: a feeding level Troposphere: the innermost layer of the atmosphere

9. Objectives • What is ecology? Ecology is the study of how organisms interact with one another and with their nonliving environment. In effect, it is a study of connections in nature—the house of Earth’s life.

10. What are the major components of an ecosystem? Multitudes of a species interact in groups called populations; populations of different species living and interacting in an area form a community, and a combination of communities constitute an ecosystem. Within an organism’s habitat are biotic (living) and abiotic (nonliving) factors, that affect the overall success of the ecosystem. Examples of each are: (biotic) co-inhabitants, plants, (abiotic) climate, day-to-day weather, and food supply. These factors influence the relationships between organisms, as well as their survival.

11. What happens to energy in an ecosystem? Energy in an ecosystem is neither created nor destroyed. Rather, it is passed from one trophic level to the next—10% of the usable energy from each tropic level is passed from level to level. An ecosystem survives by a combination of energy flow and matter recycling. The survival of any individual organism depends on the one-way flow of matter and energy through its body. However, an ecosystem as a whole survives primarily through a combination of matter recycling and one way energy flow. Decomposers complete the cycle of matter by breaking down organic matter into inorganic nutrients that can be reused by producers.

12. Energy Flow in an Ecosystem

13. What are soils and how are they formed? *Soil is a slowly renewed resource that provides most of the nutrients needed for plant growth. It also helps to purify water. Soil is a thin covering over land consisting of eroded rock, mineral nutrients, decaying organic matter, water, air, and microscopic decomposers. *Soil is formed when bedrock gets broken down physically, chemically, and biologically into rock fragments. This process is called weathering. Dying lichen and other organisms in the soil add organic matter. *Infiltration and leaching bring nutrients from the upper layers of the soil to the lower layers.

14. The O-horizon consists of surface litter, including leaves and animal wastes The A-horizon (topsoil) consists of clay, silt, and sand The B-horizon is subsoil The C-horizon is made up of parent material

15. Objectives, con’t. • What happens to matter in an ecosystem? Biogeochemical cycles explain the flow of matter through an ecosystem.

16. Nitrogen Cycle

17. Carbon Cycle

18. Oxygen Cycle

19. Phosphorous Cycle

20. Hydrologic Cycle

21. How do scientists study ecosystems? Scientists study ecosystems through observation and field research, in which samples are collected, technology is installed, and the area is monitored over time. Controlled experiments are also a method of gathering information, through creating and monitoring aquariums, tanks, greenhouses, etc. in a laboratory setting. These are often simplified forms of field research, and as such are more economical, and yield faster results. Finally, scientists can create models and computer simulations to predict an outcome, or to gain a general idea of a topic.

22. What basic processes keep us and other organisms alive? Multitudes of tiny microbes such as bacteria, protozoa, fungi, and yeast help keep us alive. Microbes, especially bacteria, help purify the water you drink by breaking down wastes. Bacteria in your intestinal tract break down the food you eat. Some microbes in your nose prevent harmful bacteria from reaching your lungs. Other bacteria are the sources of disease-fighting antibiotics, including penicillin, erythromycin, and streptomycin. Scientists are researching these bacteria not only to help humans in disease-fighting, but also to extract metals from ores, and help clean up polluted water and soils.