Principles of Ecology
V. Hassell
Everything on Earth- air, land, water, plants and animals=
is connected. Understanding these connections help us
keep our environment clean, healthy and safe..
Uses qualitative (descriptive) and quantitative
research

The study of

from
interactions that
take place between
organisms and their
environment
Uses techniques

Math

Chemistry, physics,
geology

Other branches of
biology
POPULATION

A group of organisms

population compete with each
of the same species
other for food, water, mates,
which can interbreed
and live in the same
area at the same time
Because members of the same
and other resources.

Competition increases when
resources are in short supply

a group of
interacting
populations of
different species
occupying a
particular place
 a pond community

The organisms
in a plant
population and
the biotic and
abiotic factors
which impact
on them.
The area on earth which supports life (where life is found)

Thin layer.

Supports a diverse group of organisms in a
wide range of climates

Living things are affected by nonliving and
living factors.


1. biotic

living or derived
from living things
2. abioticnonliving
factors;
 sunlight,
temp.
water, soil

Limits of Tolerance conditions under which growth
will occur

Optimum Range- the best conditions for growth

Limiting factors- A nutrient in short supply which
limits an organisms growth. It keeps populations
from spreading beyond areas to which they are best
adapted
2 types of Ecosystems

Terrestrial ecosystems- on land

Include forest, measows and rotting logs

Aquatic ecosystems include fresh water and
saltwater forms

Fresh water- Includes ponds, lakes, streams

Salt water – called Marine ecosystems, make up 70%
of earth’s surface

Organisms must be able to adapt to
changing conditions.

Coastal organisms spend part of the day
underwater.

Tides affect salinity (salt content)
Where an organism lives its life

Prairie dogburrows in prairie

Birds- nest in trees
or on the ground

Others- Wetlands,
ponds, oceans

1st Producer


Autotroph
Photosynthesis
plant
competition

It is an advantage

same needs can’t exist
to have a different
for long together
nich than other

One will gain control
species in the

Other become extinct,
habitat

2 species with the
Less competition
move elsewhere or
adapt

Adaptations to
survive in different
habitats include

Cypress knees

Polar bears
Organisms living together in close, permanent
association

Types

Mutualism- both species benefit

Commensalism- one species benefits, the
other is not affected

Parasitism- one benefits, one is harmed

Spanish moss

Orchids

barnacles
Harmful to one species, beneficial to another

Endoparasite

Hook worms

Do they care if their
host dies?

Exoparasiteoutside

Tick, fleas

Compare how organisms satisfy their
nutritional needs.

Trace the path of energy and matter in an
ecosystem

Analyze how matter is cycled in the abiotic and
biotic parts of the biosphere
Autotrophs


The ultimate source

Autotrophs
of energy is the sun

Producers
Plants use
 Plants
photosynthesis to
 Some protist & algae
produce food from
light energy.
Other organisms
depend on thes for
energy
Consumers are Heterotrophs

Can not make its
own food

Obtain nutrients by
eating other
organisms

Heterotrophs

Omnivore

Carnivore

Scavenger
Breakdown and release materials

Breakdown complex compounds of dead
and decaying organisms into simpler
substances

Fungi, bacteria

Matter is composed of carbon, nitrogen and
other elements

Moves through the food chain from
producers to consumers
Flow of energy

Arrows indicaate direction in which energy
is transferred

May be as few as one or two – or unlimited

Plants decomposers

Plantscowmandecomposer (bacteria)
Shows
relationships for
organisms that
feed on more
than one
species
Only 10 % of energy is passed to next level

Food chains, food webs and ecological
pyramids are all models that show how energy
moves in only one direction through the tropich
levles of an ecosystem

Some energy lost to heat

Sunlight is souce

energy is neither lost or gained. Some is
transferred at each tropic level enerters the
environment as heat, but the total amount
of energy remains the same.

Each level in a
pyramid of biomass
represents the
amount tht the
level above needs
to consume to meet
it’s needs
Matter is recycled (never lost) and is not replenished like
energy from sunlgiht

There is a finite amount of matter

The atoms that make up the boies of
organisms alive today are the same atoms
that have been on Earth since the beginning
of time.
Evaporation, condensation, transpiration,
precipitation
Life on earth is a carbon based. Carbon is molecule of life
78 % of atm- not available to plants
Ammonia (urine), lightning, manure,

can cause major algae
blooms and harm an
ecosystem

causes blue baby
syndrome
All organisms need phosphorus
It is Necessary for growth and
development


Short cycle

Long cycle
Plants absorb from

Phosphates wash
into water and are
soil

Eaten, animsl dies ,
decompose and is
returned to soil
locked in rock

Millions of years
later- rock is
exposed