Unit 1-Ecology

Chapter 3-The Biosphere

Ecology

Study of interactions

among organisms &

between organisms and

their environment

Ernst Haeckel

1866 coined word “ecology”

Based on oikos = “house”

Biosphere

The portion of the Earth that supports life

Composed of two parts:

1. Biotic factors – the living organisms that inhabit

an environment • All organisms depend on others directly or indirectly for food, shelter,

reproduction, or protection

2. Abiotic factors – the nonliving parts of an

organisms environment • Air currents, temperature, light, moisture

• Have effect on living things and often determine which species can survive

in an area

Levels of organization in ecology

In Ecology, we begin with the

individual and move through the

levels to the planet, Earth

Species

Group of organisms with similar characteristics

Able to breed and produce fertile offspring

Species Hybrid

Populations

Group of individuals

(of the same species)

that live in the same

area

Example?

All the fire ants in

a pasture

Community

Groups of different

populations that live

together

Examples?

All the ants, birds,

grass, cows, etc

in a pasture

Ecosystem

Collection of all organisms (biotic) that live in a particular area, together with their non-living (abiotic) parts of an environment

Examples of abiotic factors??

Climate, soil type, amount of rainfall, etc

Southern Pine Ecosystem

Fort Bragg, North Carolina

Levels of organization in an

organism

Chemicals make up cells…

Which make tissues…

Organs…

Systems…

And finally, the individual organism

Community Ecology

Habitat – a specific place where an organism

lives out his life

Niche – the role an organism

plays in the environment

Symbiotic Relationships – two

organisms living together

1. Competition (-/-)

compete for limited resource

Food, mate, territory

2. Predation (+/-) – Hunt and kill your prey

3. Parasitism (+/-)

4. Mutualism (+/+)

lichens (algae & fungus)

5. Commensalism (+/0)

barnacles attached

to whale

Symbiosis

Mutualism

The act of two organisms utilizing one another.

Both thrive and help each other.

Commensalism

The act of one organism utilizing another living

organism. One thrives and the other is neither

harmed nor helped

Parasitism

The act of one organism feeding upon another

living organism. The parasite thrives and the host

is harmed.

commensalism

predation competition

mutualism

+/0

+/+

+/-

-/-

Symbiotic Relationships

Herbivores (a.k.a. primary

consumers)

feed directly on

producers

Types of Consumers:

Carnivores (a.k.a.

secondary consumers)

feed on other animals

Types of Consumers:

Omnivores

feed on both plants

and animals

can be either primary

or secondary

consumers,

depending on food

chain

Types of Consumers:

Scavenger

an animal or other organism that feeds on

dead organic matter

Decomposers/Saprophyte/Detritivores

feed on (and recycle) dead or decaying matter

completing the chain, by returning nutrients needed by producers to the environment

Scavengers eat dead

things but do not recycle

Decomposers feed on dead

things AND recycle them

Types of Consumers:

Energy flow through the biosphere

Autotrophs (producers) organisms that make their own food

Heterotrophs (consumers)

Rely on other organisms for their food supply

What’s the ultimate source of energy for all life?

AUTOTROPHS

Water + CO2 Sugar + O2

HETEROTROPHS

Sugar + O2 water + CO2

Food chain

Series of steps in which organisms transfer energy by eating and being eaten

Arrow always points to the consumer

Food Chain

The pathway of

energy that

DECREASES as

it passes through

the trophic

(feeding)

levels Trophic level of an

organism is the position it

occupies in a food chain

Food web

Network of complex

interactions, linking

all of the food

chains together

Show ALL the

possible feeding

relationships

Many connections

throughout

ecosystem

Ecological Pyramids

Energy Pyramid

Biomass Pyramid

Pyramid of numbers

Hawk-eye Question: Why are they shaped as a pyramid?

What is the relationship between the numbers of

producers and Consumers?

How does this relate to the energy flow through the

ecosystem?

pyramid of numbers

So fewer and fewer

organisms can be

supported at each level

ONLY 10% of energy is passed on to next level Energy Pyramid

Biogeochemical cycles:

Water (hydrologic) cycle

Driven by solar energy

Recycles water, which is primary component of all life

Phosphorus

Cycle driven by decomposing

bacteria & fungi

phosphorus is an

important component of

ATP, Nucleic acids, &

phospholipids

Carbon Cycle The Carbon Cycle is driven

mainly by TWO processes:

Photosynthesis the process

by which producers convert

sunlight into a useable form

of energy

Cellular Respiration overall

process by which the body

gets and uses oxygen and

gets rid of carbon dioxide

CO2 in

Atmosphere

CO2 in Ocean

Nitrogen Cycle driven by decomposition by nitrifying bacteria and fungi

atmospheric nitrogen must be converted to a usable (by plants) form

N2 in Atmosphere

NH3

NO3 –

and NO2 –

Ecological Succession

IV. Ecological Succession transition in species composition over time

SLOW process, can take years or decades

usually occurs after a disturbance

Two types: Primary and Secondary

Mt. St. Helens

1. Primary Succession

Takes place over land where there are NO living organisms.

Ex. Bare rock, volcano created new island

Succession of Species

lichens & mosses grasses

trees bushes & small trees

pioneer species

climax forest

compete well in high sunlight

more shade tolerant species

shade tolerant species

stable community

2. Secondary Succession

Existing community cleared, but base soil

is still intact

Ex. Forest fire, harvesting, hurricane

burning releases

nutrients formerly

locked up in the

tissues of tree

the disturbance

starts the process

of succession

over again

IIV. Species diversity

• Greater biodiversity offers:

more food resources

more habitats

more resilience in face of environmental change

Greater diversity = greater stability