Intro to Ecology Notes

QQ#1: What is Ecology?

What is Ecology?▪ The study of

interactions among organisms and between organism and their environment, or surroundings.

▪ Basically…– Why animals are where

they are and how they interact.

Levels of Organization▪ To understand these

relationships within the biosphere, scientists ask questions about events and organisms that range in complexity from a single individual to the entire biosphere.

QQ#2: What is a species?

Levels of Organization

▪ Species: a group of organisms so similar to one another that they can breed and produce fertile offspring

Levels of Organization▪ Populations: Groups

of individual of the same species that live in the same area

Levels of Organization▪ Communities: two or

more populations that live in a defined area.

QQ#3: What is an ecosystem?

Levels of Organization▪ Ecosystems: collection

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

Levels of Organization▪ Biome: group of ecosystems that have the same

climate and similar dominant communities

What Shapes an Ecosystem?

Biotic and Abiotic FactorsNiche

Community InteractionsSuccessions

Biotic and Abiotic Factors◊ Biotic factors:

• Biological influences on organisms within an ecosystem

• Living or once-living

◊ Abiotic Factors:• physical factors

that shape an ecosystem

• Non-living

BIOTIC ABIOTIC

QQ#4: What are some examples of biotic factors? abiotic factors?

Biotic and Abiotic Factors◊ Examples of Biotic

factors:• Plants and animals• Aquatic (water)• Benthic (bottom-

dwelling)• Terrestrial (land)

◊ Examples of Abiotic Factors:

•Temperature•Water •Sunlight •Salinity - amount of dissolved salt

•Wind, rocks and soil•Catastrophes - earthquakes, fires, floods, landslides, toxic spills

Biotic and Abiotic Factors◊ Biotic and abiotic factors

determine the growth and survival of an organism

◊ Also determine the productivity of the ecosystem in which an organism lives

◊ Habitat: area where an organisms lives (biotic and abiotic included)

Niche◊ Niche: the full range of physical

and biological conditions in which an organism lives and the way the organism uses those conditions.• Place in the food web

◊ Food it eats, how it obtains it, etc.

• Physical conditions needed to survive◊ Temperatures it can survive in

Niche◊ No two species can share the same

niche in the same habitat.◊ Can occupy different niches that are

very similar.

Community Interactions◊ Organisms that live together in

ecological communities constantly interact.• Competition• Predation• Symbiosis

◊ All affect an ecosystem

Competition

◊ Occurs when organisms of the same or different species attempt to use a resource at the same place and time.• Resource: any necessity of life (water,

food, light, space, etc.)

Competition

◊ Direct competition• Results in a

winner and a loser• Losing organism

fails to survive.

QQ#5

◊ A bear catches and eats a fish for food.

◊ Who benefits?◊ Who doesn’t?

Predation◊ An interaction in

which one organism captures and feeds on another organism

◊ Predator: the one that does the killing/eating

◊ Prey: the one being eaten

Symbiosis◊ Any relationship in which two

organisms live closely together• Means “living together”

◊ 3 Main classes in nature:• Mutualism• Commensalism• Parasitism

QQ#6◊ The ant cares for

the aphids and protects them from predators. The aphids produce a sweet liquid that the ant drinks.

◊ Who benefits? Who doesn’t?

Mutualism

◊ Both species benefit from the relationship

Clownfish and Sea Anemone

Bee and Flower

QQ#7◊ The orchid benefits from its perch

in the tree as it absorbs water and minerals from rainwater and runoff.

◊ Who benefits? Who doesn’t?

Commensalism

◊ One member in the relationship benefits, while the other is neither helped nor harmed.

Barnacles and Whales

QQ#8

◊ A tick feeds on the blood of its host and may also carry disease-causing microorganisms.

◊ Who benefits? Who doesn’t?

Parasitism◊ One organism lives

on or inside another organisms and harms it.

◊ Parasite obtains all or part of its nutritional needs from the host

◊ Generally weakens but does not kill their host a tomato hornworm is covered

with cocoons of pupating braconid wasp

Ecological Succession

◊ Ecosystems are constantly changing due to natural or human disturbances.

◊ Older inhabitants gradually die out and new organisms move in, causing changes in the community.

Ecological Succession◊ Ecological Succession: series of

predictable changes that occur in a community over time.

◊ Succession may result from:• Slow changes in physical environment• Sudden disturbance from human

activities

Primary Succession

◊ Occurs on surface where no soil exists.• Where lava rock is

from volcanic explosion

• On rock exposed when glaciers melt

Primary Succession

◊ Pioneer species: first species to populate the area

◊ On volcanic rock, often lichens (fungus and aglae that can grow on bare rock)• When they die, add organic material to help

form soil for plants to grow.

Secondary Succession

◊ When the natural or human disturbance is over, community interactions tend to restore the ecosystem to its original conditions.

Succession in a Marine Ecosystem

◊ Occurs when a large whale dies and sinks to the bottom.

◊ Attracts scavengers and decomposers.◊ Decomposition of body enriches surrounding

sediments.◊ Heterotrophic bacteria decompose oils in bone that

release chemical compounds that serve as energy sources.