ECOSYSTEMS

New Vocabulary

Ecology: is the scientific investigation and analysis of interactions among organisms, populations, and communities and their responses to external factors in their environment

Ecosystem: all organisms that live in a place, together with their physical environment

New Vocabulary

Biosphere: consists of all life on Earth and all parts of the Earth in which life exists Ex: land, water, and the atmosphere

Biome: is a group of ecosystems that share similar climates and typical organism

Levels of Organization in Ecology

What is the correct level of organization?

atom molecule organelle cell tissue organ organ system organism population community ecosystem

Populations vs. Communities

What is the difference between a biological population and a biological community?

A biological population is “a group of organisms of one species that interbreed and live in the same place at the same time

biological community is “a group of interdependent organisms living and interacting with each other in the same habitat.”

Limiting Factors

Do populations often grow exponentially?

What are limiting factors? Limiting factors are any factors (things)

that affect an organism’s ability to survive in its environment. These factors affect population growth.

Examples? Availability of food and water, predators,

temperature, space/shelter, and disease

Density-Dependent Factors

What are density-dependent factors? Factors that depend upon the size of the

population. These factors will have an increasing effect as the population size increases.

Examples? Availability of food and water,

competition, predators, and disease

Competition What is competition?

Competition is “a symbiotic relationship between or among living things for resources, such as food, space, shelter, mate, ecological status, etc.”.

Examples? Trees that grow very close together vie for

sunlight and soil nutrients, lions and tigers that vie for similar prey, and a farm of rice paddies with weeds growing in the field

Competition

What happens to competition between individuals as population size increases?

Competition will also increase. If the demand for resources exceeds the

supply, then the population size will eventually decrease.

Density-Independent Factors

What are density-independent factors? Factors that are not dependent upon the

size of the population and can affect any population.

Examples? Temperature, weather (storms, floods,

drought), and habitat disruption by humans

Carrying Capacity

Carrying capacity is the “largest number of individuals of a particular species that can survive over long periods of time in a given environment.”

Why is knowing carrying capacity important to ecologists?

Symbiotic Relationship

Symbiotic: relationship in which two species live close together

Types of symbiosis Mutualism Commensalism Parasitism predation

Mutualism

A symbiotic relationship in which both organisms benefit

Examples Clownfish and sea anemone

Commensalism

A symbiotic relationship in which one organism benefits and the other neither benefits nor harmed

Examples Shark and Pilot fish

Parasitism

A symbiotic relationship in which on organism benefits and the other is harmed

Examples Tapeworms, liver flukes, fleas, ticks,

roundworms, hookworms

Predation

A symbiotic relationship in which one organism preys on (and eats) another organism

Examples Lion and zebra

Discussion

What kinds of relationship do humans have with other organisms?

What are some examples of these relationship?