Chapter 3 Answers

3) Soil Horizon: horizontal zones that make up a particular mature soil. Each horizon has a distinct texture and composition that vary with different types of soil.
-Soil Layers
A horizon: top soil. Mixture of hummus (partially decomposed organic material) and some inorganic mineral particles.
B horizon: subsoil
C horizon: parent material
4) Fertile soil has a thick top soil with a lot of hummus. Dark brown or black topsoil means the soil is rich in nitrogen and organic matter. Loam topsoil is the best for plants, it is the perfect mixture of clay, silt, sand, and gravel. Loam's texture is crumbly and spongey and its particles are loosely clumped together. Soil should be pourous enough to absorb water without preventing infiltration or leaching.
(#3-4 by Eliza Lasky, 5th period)

hey guys- might be some info missing from here so feel free to add!! - Christine

1. Ecology is the study of connections in nature. (how organisms interact with one another and with their nonliving environment. Matter is divided into species, populations, communities, ecosystems and biospheres.

2. Lithosphere: the earth’s crust and upper mantle. Hydrosphere: the earth’s water (liquid, ice, and water vapor) Atmosphere: a thin envelope or membrane of air around the planet. Ecosphere: zone of earth where life is found. (same as biosphere)
Solar energy, the cycling of matter (nutrients), and gravity sustain the earth’s life. Solar energy provides energy in food matter, the cycling of nutrients recycles earth’s limited supply of resources, and gravity enables movement of chemicals between air, water, soil, and organisms in the matter cycles.

5. Biogeochemical Cycles
The hydrologic cycle: a vast global cycle that collects, purifies, distributes, and recycles the earth’s fixed supply of water. Humans alter it by withdrawing large amounts of fresh water, clearing vegetation and eroding soils, and polluting surface/underground water.
Collects, Purifies, and Distributes Water
-Solar energy evaporates water from Earth's surface
-Water returns to Earth as precipitation
*some is locked in glaciers
*some infiltrates (downward movement) and percolates (horizontal movement) under ground into aquifers
*some becomes surface runoff, which flows into streams, lakes, and eventually the ocean, and the cycle begins again
-Causes soil erosion, dissolves nutrients (transports nutrients within/between ecosystems), and purifies (evaporation and precipitation act as a natural distillation process; flowing water is filtered/purified by chemical and biological processes)

Carbon Cycle: Carbon recycles through the earth’s air, water, soil, and living organisms. It mainly cycles through the respiration of organisms along with oxygen and hydrogen, but some carbon buried underground turns into fossil fuels that are later expelled into the air. Human activities such as burning fossil fuels and clearing photosynthesizing vegetation faster than it is replaced can increase earth’s average temp by adding excess co2 to the atmosphere.
Based on photosynthesis and respiration
-Produces remove CO2 from atmosphere and convert it to complex carbohydrates
-Consumers and decomposers metabolize producers and carry out aerobic respiration, releasing CO2
-Buried dead matter is compressed into fossil fuels, which release CO2 when burned

Nitrogen Cycle: Different types of bacteria help recycle nitrogen through the earth’s air, water, soil, and living organisms. First step = nitrogen fixation: soil/aquatic bacteria convert gaseous N to ammonia for plant use. Then, nitrification occurs where soil bacteria convert ammonia to nitrite ions, and then to nitrate ions. Roots take up the nitrate ions and then animals eat/expel them. Ammonification occurs, where bacteria convert detritus to compounds. In denitrification, bacteria in waterlogged soil convert the compounds into gas. Humans add large amounts of nitrogen-containing compounds to the earth’s air and water and remove nitrogen from soil.

Phosphorus Cycle: Phosphorus cycles fairly slowly through the earth’s water, soil, and living organisms. Phosphate sediments are mined from the ocean and terrestrial rock formations for fertilizer, circulated in land food webs, washed back to the ocean, then circulated in marine food webs. Phosphate is also circulated by birds when they excrete and form reserves of phosphates in guano. Humans remove large amounts of phosphate from the earth to make fertilizer, reduce phosphorus in tropical soils by clearing forests, and add excess phosphates to aquatic systems.

Sulfur Cycle: Sulfur cycles through the earth’s air, water, soil, and living organisms. It is released from active volcanoes and organic swamp matter, from sea spray, dust storms, and forest fires, but mostly exists underground or under the ocean in rocks and minerals. Humans add sulfur dioxide to the atmosphere by burning coal and oil, refining oil, and producing some metals from ores. In the atmosphere, sulfur dioxide is converted to sulfuric acid and sulphate salts, which fall to Earth as acid deposition, harming both terrestrial and aquatic organisms.
(Elizabeth)

6. Abiotic component of an ecosystem: nonliving such as water, air, nutrients, and solar energy.
-Physical factors include: sunlight, temperature, pressure*, and precipitation
-Chemical factors include: salinity*, dissolved oxygen*, and nutrient availability
(*aquatic ecosystems)
(Elizabeth)

7. Law of Tolerance: the existence, abundance, and distribution of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the range tolerated by that species. (species thrive where conditions are best for them)

Terrestrial limiting factors: precipitation, soil nutrients Aquatic limiting factors: temperature, sunlight, nutrient availability, dissolved oxygen content, salinity

8. Biotic component of an ecosystem: living biological components such as plants, animals, and microbes. Producers: organisms that make their own food from compounds obtained from the environment (aka autotrophs. Ex. Plants, algae, and phytoplankton). Photosynthesis: producers capture sunlight to make complex compounds. Chemosynthesis: some producers convert simple compounds from their environment into more complex nutrient compounds without sunlight.
Consumers: organisms that obtain energy and nutrients by feeding on other organisms of their remains. Carnivores feed on meat Omnivores feed on both plants and animals Herbivores feed on plants Decomposers (mostly bacteria and fungi) recycle organic matter in ecosystems Detritivores (a kind of decomposer) feeds on detritus (debris) to get nutrients

Aerobic respiration: oxygen converts organic nutrients back into carbon dioxide and water Anaerobic respiration: ??

9. Food Chains: a sequence of organisms, each of which serves as a source of food for the next, determining how energy and nutrients move from one organism to another through the ecosystem.
Food Web: a complex network on interconnected food chains.

Energy becomes less useful as it is transferred, therefore, animals at higher trophic levels consume food with less energy. (that’s why they eat more)

Pyramids of numbers and biomass might change depending on the size and amount of trophic levels from year to year, but the pyramid of energy flow is always consistent because energy is always lost at higher levels.

10. The ecosystems that show the highest ave. net primary production (NPP) are tropical rain forests, swamps and marshes, and estuaries. The open ocean contributes most to the global NPP.

11. Field research involves going into nature and observing and measuring the structure of ecosystems and what happens in them. Recently geographical information systems have been used to store info

Laboratory research is used to set up, observe, and make measurements of model ecosystems and populations under lab conditions. System Analysis: ecologists develop mathematical and other models to simulate the behavior of ecosystems.

12. Ecosystem services: Natural services or natural capital that support life on the earth and are essential to the quality of human life and the functioning of the world’s economies.

Principles of Sustainability:

Our lives, lifestyles, and economies are totally dependent on the sun and earth Everything is connected to, and interdependent with, everything else. We can never do just one thing (always side effects) We cannot indefinitely sustain a civilization that depletes and degrades the earth’s natural capital, but we can sustain one that lives off the biological income provided by the earth’s natural capital.

Christine Donaldson (period 5)

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License