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Ecology
The study of interactions of
living organisms with one
another and with their
environment
Habitat is the place a
plant or animal lives,
while its niche is its total
way of life.
Niche
Abiotic


The physical non –
living parts of a
habitat.
include climate,
soil, temperature,
water, air, sunlight,
humidity, pH, and
atmospheric gases.
Biotic


The living
organisms in a
habitat.
includes plants,
animals, fungi, &
microorganisms.
They may be
producers,
consumers, or
decomposers.
Organism

Any single living thing
Population

Members of the same species living in
one place.
Community
All the populations living in an area (habitat).
Ecosystem
Is made up of a community
and all the physical aspects of a
habitat
(such as soil, water, and weather).
Biosphere

All living & nonliving things on earth.
Biome
Ecosystems covering wide
areas & with similar climates &
organisms
There are many types of Biomes:
•Water
•Tropical rain forest
•Deserts
•Temperate forest
• Coniferous forests
•Savannas
•Chaparral
•Tundra
•Temperate grasslands
Water

Water
– Marine
– Fresh
Aquatic Biomes

Oceans cover about 75% of the Earth’s surface

Light and the availability of nutrients are the
major factors that shape aquatic communities.
Deserts
Temperature: very hot,
and cold (Antarctica!)
 Rainfall: dry
 Plants: none, deep rooted shrubs,
succulents.

– waxy coating to prevent water loss
– many seeds that remain dormant until it rains


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Sunlight: extreme
Habitats: burrows, active at night
Animals: ants, birds, rodents, lizards,
snakes, & hawks.
Temperate
forests






Temperature: cold winter, hot summer
Rainfall: high precipitation
Plants: deciduous trees (oak, hickory, maple)
Habitats: rich soil, leaf litter, burrow
Animals: invertebrates, mice, shrew, squirrels,
birds, bobcats, foxes, bears, & mountain lions.
Most destroyed by loggers & urban
development.
Coniferous forests
Taiga



Temperature: long cold winters, short wet
summers
Rainfall: considerable precipitation (snow)
Plants: cone bearing evergreens
– (spruce, pine, fur)
Habitats: soil thin & acidic
 Animals: moose, elk, bears,
wolves, hares, migratory birds.
 Heavily logged.
 Largest terrestrial biome!

Tropical
forests





Temperature: warm
Rainfall: varied - heavy
Plants: thorny shrubs, deciduous trees, &
succulents. (very diverse)
Sunlight: little reaches the forest floor.
Habitats: floor –> canopy.
– Poor soil, due to high temp & heavy rains
(leaching).

Animals: monkeys, birds, snakes, bats,
frogs – tree dwelling.
Savannas



Temperature: warm year round
Rainfall: moderate rainfall
Plants: grasses & scattered trees.
– growing point below ground & resistance to
periods of drought.

Habitats: migratory
– Poor soil, lack of moisture, grazing animals, &
fires inhibit most trees.

Animals: large grazing mammals, insects,
burrowing animals, predators (lions &
cheetahs).
Chaparral



Temperature: mild winter, hot summer
Rainfall: rain in winter, dry in summer
Plants: dense shrubs with tough evergreen
leaves. Seasonal plants.
– Food reserves in roots allow for rapid growth after
frequent fires.
– Seeds only germinate
after hot fire.

Animals: deer, birds, rodents,
lizards & snakes
Tundra


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Temperature: extremely cold
Rainfall: little
Plants: no trees, shrubs, grasses, mosses, and
lichens.
– Permafrost prevents deep root penetration



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Sunlight: little light for much of the winter, constant
daylight in summer
Habitats: migratory (summer is a breeding ground),
high altitude, permafrost, soil continually saturated
due to poor drainage and slow evaporation.
Animals: well insulated (oxen & caribou), lemmings,
fox, snowy owl.
During the summer, clouds of
mosquitoes fill the air due to the
Producer
Make their own food through
photosynthesis or chemosynthesis.
 Includes plants, algal protists, and
some other bacteria.

Consumer

Can’t make their own food.
– Herbivores – plant eating
– Carnivores – feed only on animals
– Omnivores – feed on plants and animals
Decomposers

Breaks down dead plants and animals
– Called Detritus
Recycles nutrients.
 They are called Detritivores

form the excrement into a small ball and roll it
into a hole that was previously dug in the
soil. They lay an egg on the ball of dung and
cover it with soil to serve as a nursery for their
larvae.
How Organisms
Interact
Predation
Parasitism
Mutualism
Commensalism
Competition
Predation
Act of one organism feeding on another
Parasitism
One organism feeds on and usually lives
on or in another.
Mutualism
A symbiotic relationship in which both
participating species benefit.
Commensalism
A symbiotic relationship in which one
species benefits and the other is neither
harmed nor helped.
Energy of Life

FOOD CHAIN: diagram showing the
relationship between organisms and
their food supply.
Energy of Life

Food web
– A network of interconnecting food chains

Keystone species
– A species whose
impact on its
community is larger
than its biomass or
abundance indicates
– Occupies a niche that
holds the rest of its
community in place
Energy of Life

Trophic structure
– A pattern of feeding relationships
consisting of several different levels
Each level receives
only one-tenth the
energy available to the
previous level.
90% of the energy is
lost as heat.

A pyramid of production
– Illustrates the cumulative loss of energy
transfer in a food chain (90%)
Energy of Life

Producers
– Support all other trophic levels
– Autotrophs
–
Photosynthetic producers
– Plants on land
– Cyanobacteria in water

Consumers
– Heterotrophs
–
–
–
Primary consumers (1)
Secondary consumers (2)
Tertiary consumers (3)
1
2
3

Also applies to humans!
Succession

Succession: the series of ecological
changes that every community
undergoes over long periods of time.
– A success of change gradually replaces
other species
Succession

Primary succession
– Begins in a virtually lifeless area with no
soil

Secondary succession
– When a disturbance destroyed an
existing community but left the soil intact
 Disturbance
= Storms, fire, floods, droughts,
overgrazing, or human activity
Cycles

All the organisms in a community as
well as the abiotic environment

Components of ecosystems
– Energy flow
–
Passage of energy through the ecosystem
– Chemical cycling
–
Transfer of materials within the ecosystem
Oxygen Cycles
OXYGEN CYCLE:
1.
2.
3.
4.
Plants take in water, carbon dioxide, and
sunlight
Through photosynthesis, plants produce
oxygen and food (glucose) to provide their
energy
Animals take in oxygen and food (glucose)
produced by plants
Through cellular respiration, animals
produce water, carbon dioxide, and energy
for their use.
Water Cycle
1.
2.
3.
4.
5.
6.
Water comes to Earth in the form of precipitation
and is stored in oceans, lakes, and rivers.
All living things take in water and release water
to the atmosphere.
Plants release water through TRANSPIRATION:
loss of water through the leaves of plants
Animals release water through evaporation and
respiration.
Once in the atmosphere, water condenses in
clouds and precipitation occurs.
The sun provides the heat energy required for
the cycle to continue.
Carbon Cycle
Carbon is the major ingredient of all
organic molecules
 The return of CO2 to the atmosphere
by respiration closely balances its
removal by photosynthesis
 The carbon cycle is affected by
burning wood and fossil fuels

Nitrogen Cycle
Nitrogen is an essential component of
proteins and nucleic acids
 Nitrogen has two abiotic reservoirs

– Air
– Soil

Nitrogen fixation converts N2 to
nitrogen used by plants
– Carried out by some bacteria and
cyanobacteria