The Biosphere

• Ecology is the scientific study of interactions among organisms and between organisms and their physical environment.
• Levels of Organization:
1)individual organism (A species is a group of similar organisms that can breed and produce fertile offspring.) ex-zebra
2)population- a group of individuals that belong to the same species and live in the same area;exgroup of zebras

3)community- an assemblage of different populations that live together in a defined area; ex-group of zebras, group of lions, group of elephants
4)ecosystem-all the organisms that live in a place, together with their physical environment; excoral reef & all abiotic factors that affect it
5)biome-a group of ecosystems that share similar climates & typical organisms;ex-tundra, desert,etc.

6)biosphere-all life on Earth and parts of the
Earth in which life exists, including land, water, and the atmosphere
What are abiotic and biotic factor?
*abiotic factors-any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, soil types, and so on.
*biotic factors-any living part of the environment with which an organism might interact, including animals, plants, mushrooms, and bacteria.

What Is abiotic and biotic?
What is grass? Clouds? Air? Trees? Wind?

• Autotrophs(producers)- organisms that make their own food through photosynthesis or chemosynthesis;ex-algae, certain bacteria, and plants
• Heterotrophs(consumers)-organisms that rely on other organisms for energy and nutrients
Types of Consumers
1)Carnivores-meat eaters; ex-snake, frog, fox

2)Herbivores-plant eaters; ex-cow, deer
3)Omnivores-eat both plant & animal; exbears,pigs
4)Scavengers-animals that eat the carcasses of other animals that have been killed by predators or other causes; ex-vulture
5)Decomposers-organisms that feed by chemically breaking down organic matter; exbacteria & fungi(like mushrooms)

6)Detritivores-organisms that commonly digest decomposers that live on, and in, detritus particles;ex-earthworms, mites, snails, shrimp, and crabs
*primary producers-the 1 st producers of energy-rich compounds that are later used by other organisms
*photosynthesis-captures light energy & uses it to power chemical reactions that convert carbon dioxide & water into oxygen & carbohydrates

*chemosynthesis-process in which chemical energy is used to produce carbohydrates; takes place in deep-sea volcanic vents, hot springs, and tidal marshes along the coast
How does energy flow through ecosystems?
Energy flows through an ecosystem in a one-way stream, from primary producers to various consumers

Food Chain
Food chain-a series of steps in which organisms transfer energy by eating and being eaten.
Trophic level-each step in a food chain or food web

• Food web-network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

Food Web

Energy pyramid
Pyramids of energy show the relative amount of energy available at each trophic level of a food chain or food web.

How much energy is lost from one trophic level to the next on an energy pyramid? Scientists say that on average 90% of the available energy is used for life processes such as respiration, photosynthesis, reproduction, and transformed to heat energy before an organism is consumed.
This means only about 10% of the original energy is left to feed the next level. This 10% is stored in the tissues(leaves, stems, muscles, organs, fat, etc.) of the organism.

• Water Cycle
Step 1: A large quantity of water evaporates from the surface of the ocean. Evaporation is the conversion of liquid water to a gaseous form of water called water vapor.
Step 2: The water vapor then condensed to form clouds. Most of this condensed water will then precipitate back into the ocean, but some will travel on & eventually float over land.
Precipitation means to condense from a vapor & fall as rain or snow .

Step 3: The condensed water (clouds) that floats over land picks up more water vapor from evaporation & transpiration. Transpiration is the evaporation of water from leaves of plants.
Step 4: The accumulated water vapor will then fall to the ground as rain.
Step 5: The rain water makes its way back to the ocean through streams & rivers & starts the cycle all over again

Step 1: Carbon enters the atmosphere as carbon dioxide from respiration(breathing) & combustion
(burning).
Step 2: Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis. These producers then put off oxygen.
Step 3: Animals feed on the plants. Thus passing the carbon compounds along the food chain. Most of the carbon these animals consume however is exhaled as carbon dioxide. This is through the process of respiration. The animals & plants then eventually die.

Step 4: The dead organisms (dead animals & plants) are eaten by decomposers in the ground. The carbon that was in their bodies is then returned to the atmosphere as carbon dioxide. In some circumstances the process of decomposition is prevented. The decomposed plants & animals may then be available as fossil fuel in the future for combustion.

Step 1: A special type of bacteria called nitrogen fixing bacteria take in atmospheric nitrogen and produce ammonia.
Step 2: Other bacteria use this ammonia to produce nitrates & nitrites, which are nitrogen and oxygen containing compounds.
Step 3: The nitrates & nitrites are used by plants to make amino acids which are then used to make plant proteins.

Step 4: Plants are consumed by other organisms which use the plant amino acids to make their own.
Step 5: Decomposers convert the nitrogen found in other organisms into ammonia and return it to the soil. A few of these types of bacteria return nitrogen back to the atmosphere by a process called denitrification, however this amount is small.

Step 1: Over time, rain and weathering cause rocks to release phosphate ions & other minerals. This inorganic phosphate is then distributed in soils & water.
Step 2: Plants take up inorganic phosphate from the soil.
The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil.
Step 3: Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is called mineralization.

Step 4: Phosphorus in the soil can end up in waterways & eventually oceans. Once there, it can be incorporated into sediments over time.