Unit 8

__Ecology__

the scientific study of interactions among organisms and between organisms and their environment

entire planet.

The ‘environment’ ranges in size from a single cell to the

Biosphere

The largest environment is the __**——**__– the combined

         portions of the planet in which all life exists, including

         land, water, and air.

__**Species**__

group of organisms so similar to one another that they can breed and produce fertile offspring.

__**Populations**__

–groups of individuals that belong to the same species and live in the same area

__**Communities**__

assemblages of different populations that live together in a defined area

__**Ecosystem**__

collection of all the organisms that live in a particular place, together with their nonliving environment

__**Biome**__

group of ecosystems that have the same climate and similar dominant communities

Biosphere

combined portions of the planet in which all life exists

__**Producers**__

organisms that either capture energy from the sun or chemical energy

__**Consumers**__

organisms that rely on other organisms for their energy and food supply

Herbivore

Plant eater

Carnivores

meat eater

Omnivore

Can eat both plant and meat

__**Food Chain**__

series of steps in which energy is transferred by eating or being eaten. Starts with producers and is transferred to consumers

__**Food Web**__

when the feeding relationships among the various organisms in an ecosystem form o network of complex interactions

__**trophic level**__

Each step in a food chain or food web is called a __**- -**__ producers make up the first trophic level, and consumers make up the second, third, or higher trophic levels 

__**Competition**__

when an organism of the same or different

          species attempt to use an ecological resource in the same

          place at the same time

__**Predation**__

interaction in which one organism feeds on

          another organism.

__**Symbiosis**__

any relationship in which two species live closely

         together

__**Mutualism**__

both species benefit from the relationship

__**Commensalism**__

one species benefits while the other is neither helped nor harmed.

__**Parasitism**__

one organism lives on or inside another organism and harms it.

__**Primary Succession**__

occurs on surfaces where no soil exists. Usually when a volcanic eruption occurs or bare rock

is exposed when glaciers melt

__**Pioneer Species**__

first species to populate an area

__**Secondary Succession**__

when a disturbance of some kind changes an existing community without removing the soil.

__**Population Density**__

number of individuals per unit area

        B Three factors affect population size: number of births,

            number of deaths, and the number of individuals that

            enter (immigration) or leave (emigration) the population.

Immigration

is the movement of individuals into a population, while emigration is the movement of individuals out of a population.

Slow or stops

As resources become less available, the growth of the population

Support

Carrying capacity is the number of individuals of a specific species that the environment can

defined area

Carrying capacity relies on the amount of resources available in that

Species

Will lead to either an increase or decrease in competition among

Charles Darwin

In 1831, sent out on the *Beagle* for a voyage around the world During his voyage and through his numerous observations, he would propose the theory of evolution.

__**Evolution**__

change over time. Process by which modern organisms have descended from ancient organisms.

__**Theory**__

well-supported testable explanation of phenomena that have occurred in the natural world.

__**Natural Variation**__

differences among individuals of a species. Found all the time.

__**Artificial Selection**__

nature provides the variation among different organisms, and humans select those variations that they find useful.

__**Ex**__

breeding and farming techniques

__**Struggle for existence**__

members of each species compete regularly to obtain living space, food, water, and other necessities of life.

__**Survival of the Fittest**__

individuals that are better suited to their environment survive and reproduce more successfully.

__**Fitness**__

ability of an individual to survive and reproduce in its environment.

__**adaptations**__

Increased fitness usually comes about from __**- -,**__ which is an inherited characteristic that increases an organisms chance of survival.