Transcript ECOLOGY

ECOLOGY
Dominican College, Griffith ave.
Section 1 – Factors affecting
Organisms
Environmental Factors Affecting
Organisms
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Environmental Factors
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Abiotic Factors
Biotic Factors
Climatic Factors
Edaphic Factors
Aquatic Factors
Abiotic Factors
These are non-living factors and include:
Currents: Plants and animals get washed
away. There is a need for attachments. eg
Limpets have a muscular foot: Seaweeds
have holdfasts
Steepness: Steep slopes lose water
quickly. Fewer organisms will grow higher
up the shore where it is very steep
Abiotic Factors
Exposure: Plants and animals lose
water when the tide is out. To
prevent dessication, plants and
animals have shells or mucilage.
Aspect: This is the direction a
surface faces. South facing slopes
have more plant growth.
Biotic Factors
These are living Factors:
Food: The more available food, the
more organisms that will survive. eg
More plankton…more limpets…more
dog whelks
Predation: These reduce the
number of prey. eg More dog
whelks…less limpets
Biotic Factors
Humans: May have a negative
effect on the environment. eg
Pollution
Competition: Competition for scarce
resources (food/space/light/mates).
eg Limpets and barnacles compete for
space on a rock. Seaweeds compete
for light
Climatic Factors
Refers to weather over a period of time
Temperature: Determines the rate of
reactions. eg the amount of growth in
a plant
Salinity: Organisms need to be
specialised to live in such a harsh
environment like saltwater (Crabs
have osmoregulators)
Climatic Factors
Light Intensity: This affects the rate
of photosynthesis. eg Plankton
grows best in the upper layers of
water due to the higher rate of light
intensity.
Humidity: The more the humidity,
the less the evaporation.
Edaphic Factors
Pertaining to soil.
Soil Type: Sandy soil loses water
while clay soil retains
Soil pH: Plants are adapted to
specific soil pH’s.
Humus: Vital to plant life. Binds soil
particles…retains water and
minerals… provides food for worms.
Edaphic Factors
Air Content: Oxygen is essential for
life.
Water content: Essential for life.
Mineral content: Necessary for
healthy growth.
Aquatic Factors
Light: May not penetrate too far
down into the water.
Currents: May wash away
organisms.
Wave Action: May physically
damage organisms.
O2 Conc: Not as plentiful in water as
Air.
Section 2 – Energy flow
Trophic Levels
This refers to the feeding level/stage to
which an organism belongs
Trophic Level 1
Producer
Trophic Level 2
Primary Consumer
Trophic Level 3
Secondary Consumer
Trophic Level 4
Tertiary Consumers
(PROBABLY the top
carnivore)
Energy Flow
All food is ‘grass’. ‘Grass’ absorb only
1% of the suns energy.
Producers only pass 10% of their
energy to the next trophic level.
For this reason food chains are
limited. In general should only have
a max of 4 trophic levels.
Food Chain
The simplest way to represent the
flow of energy in an ecosystem.
Plankton
Limpet
Whelk
Producer
Primary
Consumer
Secondary
Consumer
Food Web
Two or more interlinked food chains.
Food Web
Two or more interlinked food chains.
Section 3 – Definitions
Ecology
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The study of the interactions
between living things (organisms)
and between organisms and their
environment.
Biosphere
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That part of the planet containing
living organisms.
The biosphere is the living world. It
extends high into the atmosphere,
to the bottom of the ocean, and
deep down into caves.
Ecosystem
This is a group of clearly distinguished
organisms that interact with their
environment as a unit.
Habitat
A habitat is a place in which you find
animals and plants.
The kind of animals and plants which
can live in a habitat depend upon
what the habitat is like. Is it very
hot or cold? Is it very wet or dry?
Producers & Photosynthesis
Green plants are producers: this
means that they use the sun's
energy in photosynthesis to produce
new living material.
All food chains start with a producer.
Carnivores & Herbivores
Animals, fungi and bacteria are all
consumers. They get their energy
by eating other living things.
Primary consumers eat plants, we
also call them herbivores. Some
herbivores, like limpets, graze on
plants.
Carnivores are secondary consumers,
they eat other animals.
Carnivores
Omnivores
Some animals can choose between
being a herbivore and being a
carnivore: they eat both animals
and plants and they are called
omnivores.
They are either primary or secondary
consumers.
Scavengers
Scavengers are also consumers, but
they wait for their prey to die first.
eg. Sandhoppers and bacteria
Niche*****
This is the functional role of an
organism in an ecosystem or
habitat (The feeding role of the
organism).
 What it eats
 What it is eaten by
 How it interacts with others and
with its abiotic environment.
Pyramid of Numbers
Represents the number of organisms
at each stage (trophic Level) in a
food chain. (Makes it easy to
compare numbers at a glance).
Pyramid of Numbers Cntd
Normal Pyramid of Numbers:
Gull
Starfish
Mussels
Plankton
Pyramid of Numbers Cntd
Inverted Pyramid of Numbers:
Hawk
Blackbirds
Spiders
GreenFly
Oak Tree
Pyramid of Numbers Cntd
Inverted Pyramid of Numbers:
Pyramid of Numbers Cntd
Parasitic Pyramid of Numbers:
Mites
GreenFly
Rose Bush
Section 4 – Recycling
Nutrient Recycling
This is the way in which elements or
minerals are:
 Absorbed by organisms
 Released when organisms die
 Absorbed by other organisms
Elements are exchanged between the
living and non-living components
The Carbon Cycle
Carbon is normally exchanged in the
form of CO2.
The carbon cycle is the way in which
CO2 is taken from and added to the
environment
The Carbon Cycle
The Carbon Cycle
The Carbon Cycle
The Carbon Cycle
3 groups of organisms have roles to play.
 Plants – Remove Carbon by Photosynthesis
and release it by Respiration
 Animals obtain Carbon by eating plants and
release it by Respiration
 Microbes decompose dead materials and
return Carbon to the environment
The Nitrogen Cycle
The Nitrogen Cycle
The Nitrogen Cycle
Human Impact on ecosystems
A.
B.
C.
Pollution
Conservation
Waste Management
A) Pollution
Any undesirable change to the
environment.
 Domestic – household waste
 Agricultural – disposal of slurry
sileage effluent as well as overuse
of fertilisers
 Industrial – smoke causing acid rain
Case Study 1: Air Pollution and the
Depletion of the Ozone Layer
Ozone is a gas that surrounds the earth and
protects the earth from the harmful UV
rays.
The Cause:
It is being depleted by the use of:
 CFC’s in aerosols
 Freon gas in fridges
 Industrial detergents
Case Study 1
The Effects:
 Increased numbers of skin cancers
 Serious damage to crops
 Concern that Plankton numbers will
be depleted……less food……less
organisms
Case Study 1
The Control:
 Reduction of use of CFC’s
 Replacement of CFC’s with HFC’s
which break down more quickly
 Don’t dump fridges into landfill
which will release the freon gas.
Case Study 2 – Excessive Fertiliser or
Animal Waste on Grassland
The Cause:
 Excessive fertiliser or animal wastes
may wash into streams.
Case Study 2
The Effect:
 The minerals in the fertiliser cause
algae to grow in the water.
 The oxygen in the water gets used
up.
 All living things die
(Process is called eutrophication)
Case Study 2
Case Study 2
The Control:
 Limit the use of fertilisers so that
excess is not washed away.
 Slurry (animal waste) should only
be spread on grassland when the
weather is dry
B) Conservation
The wise management of our existing
natural resources in order to allow
as many species as possible to
survive.
B) Conservation – One Practice
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Don’t destroy hedges (food for
birds)
Reduce fishing quotas
Use of larger mesh size when netfishing
C) Waste Management
The basic principle here is that the
waste produced is recycled in a safe
manner.
eg Animal waste in the form of slurry
is stored in concrete pits (no
leakage), only spread in dry
conditions and never near lakes or
streams
Waste Management Cntd.
Minimised:
 Reduce
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Re-use
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Recycle
Waste Management Cntd.
Problems with waste disposal:
Waste may contain disease causing
microbes
Landfills are smelly and rodent
infected
Toxic chemicals may leak into the
water table
Waste Management Cntd.
Role of Microbes:
Break down the biodegradable
matter
Small amounts of sewerage
released into rivers/sea are broken
down by the bacteria and fungi that
live naturally there
Waste Management Cntd.
Role of Microbes:
Bacteria and fungi are used in
secondary sewerage treatment.
Primary treatment involves
screening (getting rid of plastic
containers etc. )and sedimentation
(separating solids sludge from
water!)
Waste Management Cntd.
Role of Microbes Cntd:
Secondary treatment is where the
sludge is placed into an enclosed
tank and broken down by bacteria.
Methane is produced in the process
and may be collected and used as a
fuel source
Waste Management Cntd.
Role of Microbes Cntd:
The liquid portion is passed into
larger open shallow tanks, where
98% of the organic material is
broken down by microbes.
At the end waste waters are treated
with chlorine
Section 5 – Symbiosis
Symbiosis
Symbiosis occurs when two
organisms from different species
live, in close association, where at
least one of them benefit.
Parasitism: One species gains at the
expense of the other
Mutualism: Both organisms benefit
Parasitism
eg Lice living on a dog/human
Mutualism
eg Lichens
Structurally, lichens are among the
most bizarre of all forms of life.
That's because every lichen species
is actually composed of two,
possibly even three, distinct
species of organisms.
Mutualism Cntd.
One species is a kind of fungus.
Usually the other species is an
alga, but sometimes it can be a
photosynthesizing bacterium known
as a cyanobacterium.
Mutualism Cntd
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Fungus: Absorbs water and
minerals
Algae: Carries out photosynthesis