ecology dominican college, griffith ave.. section 1 – factors affecting organisms
TRANSCRIPT
ECOLOGY
Dominican College, Griffith ave.
Section 1 – Factors affecting Organisms
Environmental Factors Affecting Organisms
Environmental Factors 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 holdfastsSteepness: 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 whelksPredation: These reduce the number of prey. eg More dog whelks…less limpets
Biotic Factors
Humans: May have a negative effect on the environment. eg PollutionCompetition: 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 timeTemperature: Determines the rate of reactions. eg the amount of growth in a plantSalinity: 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 retainsSoil 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 ProducerTrophic Level 2 Primary ConsumerTrophic Level 3 Secondary ConsumerTrophic 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 WhelkProducer Primary Secondary
Consumer Consumer
Food Web
Two or more interlinked food chains.
Food Web
Two or more interlinked food chains.
Section 3 – Definitions
Ecology
The study of the interactions between living things (organisms) and between organisms and their environment.
Biosphere
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:
Plankton
Mussels
Starfish
Gull
Pyramid of Numbers Cntd
Inverted Pyramid of Numbers:
Hawk
Oak Tree
Blackbirds
Spiders
GreenFly
Pyramid of Numbers Cntd
Inverted Pyramid of Numbers:
Pyramid of Numbers Cntd
Parasitic Pyramid of Numbers:
Rose Bush
Mites
GreenFly
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. PollutionB. ConservationC. 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
Don’t destroy hedges (food for birds)
Reduce fishing quotas Use of larger mesh size when net-
fishing
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
Re-use
Recycle
Waste Management Cntd.
Problems with waste disposal:Waste may contain disease causing microbesLandfills are smelly and rodent infectedToxic chemicals may leak into the water table
Waste Management Cntd.
Role of Microbes:Break down the biodegradable matterSmall 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 otherMutualism: 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
Fungus: Absorbs water and minerals Algae: Carries out photosynthesis