Principles of Ecology

What is Ecology?  Ecology is the study of organisms and their environment.  People have always shown an interest in nature and the environment around them…even you!  Do you have a pet?  Have you ever played outside?  Did you ever have a weather station?  Have you ever collected shells or leaves?  Have you ever watched shark week?  Ecology combines the study of biology with geology, chemistry, physics, math, and anthropology.

The Biosphere  The Biosphere is the part of the earth that supports and contains living things.  This includes the atmosphere, land, and water of earth. Although this may seem like a large space in comparison to the whole of earth it is but a small part.

Living and Nonliving Things  Anything alive is considered to be biotic.  A biotic factor is any organism that affects a particular environment.  Anything not alive is considered to be abiotic.  An abiotic factor is a nonliving thing that is part of the environment.  Air, temperature, rocks, dirt, water, heat, etc.  They are both essential parts of the environment.

Levels of Organization in the Biosphere  Organism  Species  Population  Community  Ecosystem  Biome  Biosphere

Organism  An individual living thing. It is  Made up of cells.  Uses Energy  Reproduces  Responds  Grows  Develops

Species  A group of individuals that can interbreed and reproduce.

Population  A group of organisms of the same species who live in the same geographical area together and interbreed.

Community  Several populations of different species that live in the same geographical area together.

Ecosystem  A community of plants and animals that interact with each other in a given geographic area and the abiotic parts of that area.

Biome  A large group of ecosystems that share the same type of climax community.  A climax community is what you typically see in an area.  In a rainforest:  In a coral reef:  On the South Pole:

Biosphere  The Biosphere is the portion of the earth that supports life.

Ecosystems  An ecosystem is made up of interacting populations in a community and that community’s abiotic factors.  There are some ideas and terms that we must know to understand an ecosystem: 1. Habitat-where an organism lives its’ life 2. Niche-a particular role that is filled by an organism  Only a certain number of organisms can occupy one niche at a time.  An organism must use certain adaptations and strategies to stay in its’ niche.  Think of our school…

Relationships Between Organisms  Predation  Symbiotic Relationships  Mutualism  Commensalism  Parasitism

Predation  When one organism hunts and consumes another for food.

Mutualism  Both organisms benefit from helping each other.  A bird eating food out of a crocodile’s mouth.  A clownfish and a sea anemone

Commensalism  One organism benefits and the other is not affected.  Think of a remora hanging out by a shark.  Think of a dung beetle.

Parasitism  One organisms benefits and the other is harmed.  Think of a tick or a leech.  Think of a tapeworm.

Obtaining Energy  Organisms can be either autotrophs or heterotrophs.  Autotrophs collect their energy from the sun or heat.  Heterotrophs collect their energy from other organisms (by eating them).  Carnivores eat only meat  Herbivores eat only plants  Omnivores eat both  Decomposers get their energy from breaking down dead organisms which also releases their nutrients back into the environment.

Food Chains and Food Webs  A food chain describes the flow of energy in a series of organisms  A food web contains many interconnected food chains.  A trophic level represents a feeding step in a food chain or food web.  Only 10% of the energy is passed from one trophic level to the next.  Fewer organisms make up each successive level.

Trophic Levels  Trophic levels consist of:  Producers  Primary Consumers  Secondary Consumers  Tertiary Consumers  (Sometimes) Quaternary Consumers Some organisms can fall into more than one category.

Food Chain Activity

Energy Pyramid  A model that represents all of the energy in an ecosystem.  Biomass is the total weight of all matter at each level or in the whole pyramid.

Cycles in Nature  The Water Cycle  The Carbon Cycle  The Nitrogen Cycle  The Phosphorus Cycle

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The Hunters and the Hunted 