Ecology How the World Works
Ecology is the study of interactions between living organisms and other living organisms and non living resources that they interact with. Levels of Organization Organism- a single living thing Population- all of the interacting organisms of one species in one place in a particular time period Community- all of the interacting populations that are in one particular place at one particular time
Ecosystem- The living community in an area and all of the abiotic factors that those living organisms affect and are affected by Biome- A Climactic ecosystem or group of ecosystems Biosphere- All of the ecosystems or biomes on Earth put together: The thin layer of the Earth and its atmosphere and waters that support life. Biotic factors- Living things Abiotic factors- Nonliving things
The theme of ecology is INTERCONNECTEDNESS. Ecology is the study of how all biotic and abiotic factors are interconnected. Changing numbers of living organisms of a given population or amounts of abiotic materials will result in measurable changes in other populations or materials. Ecological models- any diagram, graphic, or equation that describes or predicts interactions between factors in an ecosystem (abioticabiotic, biotic-biotic, abiotic-biotic.)
Tolerance Curve- A graphic that shows how an organism performs plotted against an environmental factor such as temperature or humidity. Acclimation- The process by which an organism or species adjusts to an environment (shifts its tolerance curve) Conformers are organisms that are dependent on their environment to control their internal conditions Regulators expend energy to maintain the optimal internal condition regardless of the external conditions
Dormancy- the period of reduced metabolic and absent intentional physical activity to sleep or hibernate through environmentally unfavorable conditions. Migration is a method of avoiding unfavorable conditions by moving to an new geographical area that has more favorable conditions. Resources- the materials that an organism needs to survive. Niche- The role that an organism has in an ecosystem. A niche is more than physical needs and donations, it includes behavior and interactions.
Fundamental niche refers to the range of conditions that an organism can potentially survive within and roles it can fill. Realized niche refers to the range of conditions that an organism actually does survive within and roles it does fill. Generalists are species that have very broad niches and large tolerances Specialists have very specific niches and usually a low tolerance for loss of resources within that niche.
Symbiosis- any one of the five types of close interactions between organisms *Predation- relationship in which one organism captures, kills, and consumes another. -Predator- consumer in a predation interaction -Prey- organism that dies in a predation interaction -Mimicry-Method of improving survival odds by looking like something you are not. Often referred to a camouflage, it can also include looking like another, more harmful or less harmful species
-Herbivores-Predators or parasites of plants -Defenses that plants have developed include spines, thick bark, mechanical responses, and secondary compounds. -secondary compounds- chemicals that are produced by plants to cause irritation, poor flavor, or even death for organisms that consume them
*Parasitism-Interaction between two organisms in which one organism is harmed while the other benefits. -Parasite- is an organism that survives at the expense of another organism. Parasites do not intentionally kill their host -Host-Organism that is harmed in a parasitic relationship -Ectoparasite- Parasites that live on the outside of their host -Endoparasite- Parasites that live inside of their host
*Competition-Interaction between two species which have overlapping niches resulting in the two species working against each other for some of the same resources Competitive Exclusion- when one species uses a resource so much more efficiently than another species that one is eliminated from an area. Character Displacement- Anatomical or habitual differences that arise in a species to avoid relying on a resource under competitive pressure Resource Partitioning- When two or more species that are competing for the same resource only utilize separate parts of that resource and prevent competition.
*Mutualism- Interaction between two species in which both species benefit. *Commensalism-Interaction between two species in which one species benefits while the other species experiences no effect. Species Richness- How many different species there are in a community. Species Diversity- How many different species there are in an area and how populous those species are in a community.
Species richness and diversity tend to increase as you approach the equator. Food Chain- a simple one dimensional diagram that illustrates energy transfer from one organism to another Food Web- two dimensional diagram that shows several ways in which energy may be transferred. This often shows how multiple food chains are interconnected and interdependent. Trophic level- defines where an organism is in regard to energy transfer. Producers make up the first trophic level, herbivores make up the second trophic level, etc.
Energy Transfer Producers- organisms that actually make energy rich molecules that can be passed through the food chain Chemosynthesis- uses high-energy chemicals to make new, biologically usable chemicals. Photosynthesis-uses the sun s energy and common chemicals to make biologically usable chemicals. Biomass- material that producers add to an ecosystem by making organic molecules. Consumers- organisms that use energy rich molecules from other organisms.
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Herbivores-consumers which eat Producers only Carnivores-consumers that eat only other consumers. Omnivores-consumers that eat other consumers as well as producers. Detritivores are consumers that eat only recently dead organisms Decomposers break complex organic molecules down into less complex molecules
Trophic levels create the energy pyramid. The energy pyramid sets trophic levels on top of one another. The most energy is always contained in producers. Herbivores which eat the producers can only contain a fraction of that energy at that level and so on. General rule of thumb, for every increase in trophic level, energy contained in that level drops to 1/10 the energy contained in the previous level. 1000 calories of phytoplankton=> 100 calories of insect => 10 calories of minnow =>1 calorie of bass
Community Stability- The ability of a community to resist change. The more diverse a community, the more it resists change. Succession- The gradual change from one community to another in an area over time. Primary succession- The development of a community in an area that has not previously supported life.
Pioneer species- Species that are hardy, very tolerant, often generalists, and quick to grow and reproduce. These are well suited to invade and occupy disturbed habitats. Secondary Succession- The replacement of one community in an area with another Climax Community- The final community in secondary succession, This community will not be replaced short of a environmental change or community destruction.
food webs, food chains, and energy pyramids help us understand species interactions. Abiotic cycles Water, carbon, oxygen, and nitrogen cycles are all crucial to life. The Water Cycle- The interaction of condensation, precipitation, runoff, transpiration and groundwater in recycling water through organisms and the environment.
Population Ecology- The interactions of populations of species in an ecosystem. Food webs are good resources to predict what will happen to connected populations as other populations are manipulated.