Ecology

Ecology  Study of the interactions between organisms and their environments.  Environmental levels of organization:

1. Biosphere  Broadest level of ecological organization.  The thin volume of Earth and atmosphere where life is found.

2. Ecosystem  Smaller unit of the biosphere.  Includes the organisms and non-living environment in a particular place.  Ex: A pond ecosystem- fish, frogs, algae, pH, temperature

3. Community  All the interacting organisms in an area.  Ex: Pond community- fish, turtles, algae and bacteria

4. Population  The members of a single species.  Ex: Population of frogs in a pond.

5. Organism  Simplest level of organization.  Ex: A frog

Where does an organism live?  Habitat: Environmental area where a species lives.

Niche  The role or interactions an organism has in its environment.  Includes: range of conditions that the species can tolerate, the resources it uses, the methods it uses to obtain resources, the number of offspring.

Generalists  Species with broad niches; they can tolerate a wide range of conditions and use a variety of resources.

Specialists  Species that have narrow niches; they are very limited in the conditions and resources they can use.

Why does it live there?  Generally depends on several environmental factors:  Abiotic  Biotic

Abiotic Factors  The physical and chemical characteristics of an environment.  Includes: soil, temperature, pH, salinity, oxygen concentration, sunlight, and precipitation, etc.  Varies by place and over time.

What is soil?  Soil: is a complex mixture of inorganic minerals, decaying organic matter, water, air, and living organisms

How is soil produced?  Produced by a process called weathering, which breaks down rocks via erosion and decomposition

Layers of Soil  Topsoil: uppermost layer that consists of twigs, leaves, insects, etc  Subsoil: consists of rock particles and minerals  Weather Rock: made of bits of rock broken (bedrock)

How Does Soil Differ?  Differs according to mineral content, pH, organic content, etc.  Differs according to location or biome that it is found in.

Biotic Factors  The living factors that affect an organism.  Includes the presence of organisms, and their interactions  Ex. Parasitism, disease, predation

Competition  When two or more species use the same limited resource.  Results in reduction of species population or elimination of one species  Example of resources: food, light, soil

Predation  Important interaction that controls population size.  Results in adaptations of both predator and prey.  Think of examples:

Camouflage  Body pattern or coloration, allows species to blend in with surroundings

Mimicry: one species resembles another  Harmless resembles a harmful

Top: Harmless species Bottom: Poisonous species

Mimicry: one species resembles another  Harmless resembles a harmful  Several harmful species resemble each other.

Various wasp species

Symbiosis  A close, long-term relationship between organisms of two species.  3 types:  Parasitism  Mutualism  commensalism

Parasitism  The host is harmed and the parasite is benefitted.  Parasites tend to be highly adapted for the host they feed on.  Ectoparasites feed outside the body.  Endoparasite live inside the body.

Examples of parasitism  Leeches, mosquitoes, tapeworms

Mutualism  Both species benefit.  Think of some examples:

Commensalism  One species benefits and the other species is unaffected.

Example: epiphyte- grows on a host plant for support.