ECOSYSTEM
ecology The branch of biology that deals with the interactions among organisms and between organisms and their environment The biotic, or living, factors include all the living organisms in the environment and their effects, both direct and indirect, on other living things. The abiotic, or nonliving, factors include water, oxygen, light, temperature, soil, and inorganic and organic nutrients
BIOTIC and ABIOTIC
ABIOTIC FACTORS Light : The energy for almost all living things on earth comes directly or indirectly from sunlight. Both the intensity, or strength, of sunlight and the duration, or length, of daylight vary with latitude Light conditions also vary in aquatic environments. Thus the amount of light present decreases with increasing depth photic zone aphotic zone, where there is no light.
2.Temperature Temperature patterns on the earth's surface vary with latitude and with altitude. Altitude is the vertical distance below or above sea level 3. Water The release of water from the atmosphere in such forms as rain, snow, dew, and fog is called precipitation 4. Soil and Minerals Soil consists of both inorganic and organic materials. The dark, rich organic matter in the topsoil is called humus. It is formed from the decay of dead plants and animals 5.
BIOTIC FACTORS Individual, a single organism The simplest grouping of organisms ina prescribe area at the same time is a population All the populations of different organisms within a given area which are potentiallyinteraction and make up a community An ecosystem includes a community and its physical environment. In an ecosystem, both the biotic and abiotic factors are included. An ecosystem includes all kinds of organisms—microorganisms, plants, and animals Biome, ecosystem in a certain area, which are largely determined by the same geographical climate The portion of the earth in which living things exist is the biosphere
NUTRITIONAL AND ENERGY RELATIONSHIPS IN AN ECOSYSTEM Autotrophs are organisms that can synthesize all the organic nutrients they need from inorganic compounds. Most autotrophs carry on photosynthesis; however, a few carry on chemosynthesis. Heterotrophs are divided into several groups, depending on what they eat and how they obtain their food. Heterotrophs include herbivores, carnivores, omnivores, and saprobes Herbivores are animals that feed only on plants. Rabbits, cattle, horses, sheep, and deer are herbivores.
Carnivores are animals that feed on other animals Carnivores are animals that feed on other animals. Among the carnivores, some are predators. Predators, such as lions, hawks, and wolves, attack and kill their prey and feed on their bodies. Omnivores are animals that feed on both plants and animals. Humans and bears are omnivores. Saprobes are organisms that obtain nutrients by breaking down the remains of dead plants and animals. Many bacteria and fungi function as saprobes.
Symbiotic Relationships Mutualism, both organisms benefit from their association, ex: Cows have a similar association with microorganisms that live in their digestive tracts. Commensalism, one organism benefits from a symbiotic relationship and the other is not affected. Ex: the remora is a small fish that lives attached to a shark by a sucker Parasitism one organism benefits from a symbiotic relationship while the other one is harmed. The organism that benefits is called the parasite, while the organism that is harmed is the host.
Producers, Consumers, and Decomposers Autotrophs (phototrophs and chemotrophs) are the only organisms in an ecosystem that can produce organic compounds (food) from inorganic compounds, they are called producers Heterotrophs must obtain nutrients from other organisms, they are called consumers Saprobes play an important role in an ecosystem. They function as organisms of decay, or decomposers. They break down the remains of dead plants and animals, releasing substances that can be reused by other members of the ecosystem. Detritivor, are groups of organism that decompose organic compounds into anorganic compound, like worm, centipede,
Food Chains and Food Webs Within an ecosystem, there is a pathway of energy flow that always begins with the producers. Energy stored in organic nutrients synthesized by the producers is transferred to consumers when the plants are eaten Herbivores, which feed on plants, are the primary consumers The carnivores that feed on the plant-eating animals are secondary consumers For example, mice feed on plants and are first-level consumers. The hawk that eats the mice is a second-level consumer. Each of these feeding relationships forms a food chain
Food Chain
Food Web There are many types of organisms at each feeding level, and there are always many food chains in an ecosystem. These food chains are interconnected at various points, forming a food web. The decomposers can be thought of as the final consumers in every food chain and food web.
Food Web
Pyramids of Energy and Biomass The amount of energy available in a food web decreases with each higher feeding level. The greatest amount of energy is present in the producers—the base of the pyramid—and the least energy is present at the top of the pyramid—the highest-level consumers. The amount of available energy in an ecosystem is commonly shown in the form of a pyramid—the pyramid of energy Since the total amount of energy available decreases with each higher feeding level, the total mass of living organisms that can be supported at each level decreases, too.
PYRAMID of ENERGY
Habitat and Niche Each type of organism within an ecosystem has a particular part of the environment in which it lives. This is its habitat. For example, slime molds live on the damp floors of forests. The role of a species in an ecosystem is its niche. An organism's habitat is part of its niche, but only part. Also included are how, when, and where it obtains nutrients, its reproductive behavior, and its direct and indirect effects both on the environment and on other species within the ecosystem.
NITROGEN LIFE CYCLE
NITROGEN of LIFE CYCLE
CARBON and OXYGEN LIFE CYCLE
WATER LIFE CYCLE
SUCCESSION
ECOSYSTEM