ECOLOGY

“Viewed from the distance of the moon, the astonishing thing about the earth… is that it is alive.” –Lewis Thomas (science writer)

What is ecology?• Ecology studies the

interactions of organisms with one another & with their physical surroundings

• "ecology" comes form the Greek work oikoswhich means "house"

Ecological Hierarchy

The Planet can be broken down into basic parts

1. Biosphere2. Ecosystems3. Communities4. Populations5. Organisms

Ecological Hierarchy• Ecologists study interactions of

organisms at a variety of levels– Individual organism, where it lives, its

prey/predators, interactions with similar/different individuals, etc…

Predator-prey relationships

• The ecology of this planet functions within several different areas in which we live and function.– Lithosphere– Atmosphere– Hydrosphere– Ecosphere/Biosphere

• Lithosphere: Earth’s crust and upper mantle – rocks and soil

• Atmosphere: Thin envelope of air around the planet – oxygen, nitrogen, carbon dioxide, ozone etc.

– Hydrosphere: Earth’s liquid water, both above and underground

– Ecosphere/Biosphere: Portion of the Earth in which living (biotic) organisms live and interact with each other and their nonliving (abiotic) environment

Ecosystems• Are a community of different species interacting with

one another (biotic factors) and with their nonliving environment of matter and energy (abiotic factors)– Can be natural or artificial– Interactions and relationships are the key– Size is arbitrary

• Abiotic factors are all the nonliving components in an organisms environment– Examples rocks,

temperature, light, humidity

• Biotic factors are all the living organisms that live in an environment– Grass, moles, fungi,

bacteria

What are some biotic and abiotic factors in this picture?

Biotic and abiotic factors determine…

• the survival and growth of an organism

• the productivity of the ecosystem in which the organism lives

Major Types of Ecosystems

1. Terrestrial (land) portion of ecosphere classified into biomes

2. Aquatic (water) portions of the ecosphere divided into aquatic life zones. Aquatic life zones are the aquatic equivalent of biomes.

Terrestrial Ecosystems– Biomes: large regions (forests,

deserts, grasslands) characterized by a distinct climate and specific life-forms, especially vegetation, adapted to it.

– Climate: long-term weather: main factor determining what type of life will thrive in a given land area

– Each biome consists of many ecosystems whose communities have adapted to differences in climate, soil, and other factors.

Aquatic Ecosystems– Two major aquatic

biomes• Freshwater: ponds,

lakes, rivers• Marine (salt water):

oceans, seas– Biomes and aquatic

life zones are each divided into numerous ecosystems.

• Communities– Community: all

organisms living in an area

– A change within 1 population in a community can cause change with another in the same community• Wolf and moose

populations on Isle Royale

• Populations – Populations: group

of organisms of one species that interbreed and live in the same area

– Compete with each other when resources are limited

– Species adapt so they can coexist with each other

• Frog life cycle

• Organisms– Organism

• Any form of life, classified into species.

– Species• Groups of organisms that

resemble one another in appearance, behavior, chemistry, and genetic endowment.

• Ability to reproduce and produce fertile offspring.

– 5 million to 100 million species exist on the earth.(estimated)

» Most are insects and microorganisms.

– Biologists know a fair amount about roughly one-third of the known species—but understand the detailed roles and interactions of only a few.

Organisms in Ecosystems• Habitat (address)= area where an

organism lives– Includes biotic and abiotic factors

• Niche (job)=full range of physical and biological conditions in which the organism lives and the way the organism uses those conditions– Ex: place in the food web, range of

temperatures the organism needs to survive, food the organism eats

Types of Niches• Potential Niche – full

range of conditions and resources an organism could use and occupy if there were no competition with other organisms.

• Realized Niche – actual range of conditions an organism uses. Not full potential because of competition with other organisms.

Types of Niches

• Realized Niche – actual range of conditions an organism uses. Not full potential because of competition with other organisms.

Types of Species1. Wild species

– One that exists as a population of individuals in a natural habitat

2. Domesticated species– One that has been

removed from normal ecological environment to support the needs and wants of humans

3. Generalist Species – have broad niche. – Live in many places, eat a variety of foods. – Are tolerant of a variety of environmental

conditions.– Examples: Raccoon, coyote, many insects

4. Specialist Species – have narrow niches – live in specific types of environments or habitats. – Tolerate only a narrow range of climate conditions, and

only eat specific foods. – Not tolerant to major environmental change. – Examples: Pandas, many plants, some amphibians, some

birds

Any Advantages between a Specialist and a Generalist?

Generalist does well in disturbed areas where there is a lot of environmental change, they can adapt.

Specialists do well in stable environments. They have a specific niche in an environment and are able to out compete a generalist.

5. Nonnative Species/Exotic species/Alien Species – species not native to a given area. – Often able to out

compete natives due to having no natural predators etc.

– They take over the niche of native species. (Blackberry, bullfrogs, Kudzu)

6. Indicator Species –species that serve as indicators that an area or an ecosystem is being damages. – Often are specialist

species due to their intolerance of environmental change. (Birds, fish, amphibians, lichen)

7. Keystone Species -plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass.

Examples: Sea Otters, Puget Sound Starfish, Prairie Dogs

Summary of Ecological Hierarchy

Species Interactions• Organisms in an ecosystem interact

constantly– Shapes the ecosystem

• Ways of interaction– Competition– Predation– Symbiosis

• Mutualism• Commensalism• Parasitism

Resource=necessity of life• Competition= when

organism try to use a resource at the same place/time– Two lizards want to eat

the same type of insect• Predation= one

organism captures and feed on another– Cheetahs

Symbiosis= two species live closely

1. Mutualism= both species benefit from the relationship

Flowers and insectsCoral and algaeMycorrhizae and plantsSharks and cleaner fish

2. Commensalism= one species benefits, the other is not helped or harmed

Whales and barnacles

3. Parasitism= One organism lives on/inside the other and harms it

TapewormTrichinellaFleasTicks