Transcript Ecosystems - Mr Goldbaum`s Biology CLass Page

Ecosystems
Ecosystems
 Ecology
is the study of Ecosystems
 Ecosystems consist of both biological and
physical factors interacting, known as
biotic and abiotic factors.
 Examples of ecosystems – marine, alpine,
desert
 Ecosystems are largely self-sustaining they can continue into the future largely
without inputs from outside the system.
 Ecosystems are the most complex level of
biological organisation.
 Biomes are broad categories of
ecosystems on a world-wide scale.
Biomes are classified largely on climate.
Biotic Factors
A
COMMUNITY is the biological part of an
ecosystem, and consists of all the different
populations of species living in one place
at a time.
 A POPULATION is all the individuals of one
particular species living in the same area
at the same time.
 DIVERSITY – the richness or number of
different species present.
– the relative distribution
(evenness) of abundance
of species.
Habitat
 Habitat
is a the type of place where
and organism lives.


Example – a water lily in a pond
Example – you in a house
 Organisms
can be limited to one
habitat or have a range of habitats
 Microhabitats are smaller localised
areas within a habitat.


Example – your bedroom in your house
Example- moss on a tree trunk in a forest
Niche
 The
role of a species within its community
 The way of life of an organism

Where an organism lives, feeds, what it
eats, when it eats, conditions it can tolerate
 Where
a species survives – it’s status in its
habitat
 Different features allow species to occupy
different niches
Ecological Communities
 Littoral
Zone – Biology Camp
 Open
Forest – Toolangi State Forest
 Mallee
Ecosystem
Ecological Groups
 Living
communities in the 3 different
ecosystems mentioned previously, contain
very different species.
 BUT - There is a common pattern to each
community.
 Members of every community can be
identified as belonging to one of the
following ecological groups:
 producers
or autotrophs
 consumers or heterotrophs
 decomposers.
Producers/Autotrophs
 Members
of an ecological community
that manufacture organic compounds
(glucose=chemical energy) from simple
inorganic compounds (carbon dioxide),
using an abiotic energy source (sunlight).
 Make chemical energy available for both
their own use and use by all other
community members of that ecosystem.
PHOTOSYNTHESIS
Examples of Producers
AQUATIC
TERRESTRIAL
MICROSCOPIC
PHYTOPLANKTON
TREES
MACROSCOPIC
ALGAE
GRASSES
SEAGRASSES
FLOWERING PLANTS AND
PINES
FRESH WATER PLANTS
FERNS/MOSSES
NB: CYANOBACTERIA (BLUE-GREEN ALGAE) ARE ALSO
PRODUCERS
CONSUMERS/HETEROTROPHS
 Obtain
energy by eating other organisms
 All animals – divided into four sub-groups:
 HERBIVORES
– EAT PLANTS eg. Caterpillars
and koalas
 CARNIVORES – EAT ANIMALS eg. Snakes,
numbats and lions
 OMNIVORES – EAT PLANTS AND ANIMALS eg.
Humans and crows
 DETRITIVORES – EAT DECOMPOSING MATTER
(detritus) eg. Earthworms, dung beetles and
crabs.
NB: Detritivores are different to DECOMPOSERS
DECOMPOSERS
 Release
enzymes to break down organic
matter outside their bodies and then absorb
some of the broken down products as their
source of chemical energy.
 Examples of broken down matter not
absorbed by decomposers are Nitrates,
Phosphates and other important mineral
nutrients which are taken up by producers.
 Eg. Various species of fungi and bacteria
Interactions Within Ecosystems
 Occur
all the time between living things
(biotic) and their physical environment
(abiotic), in every ecosystem.
 Tolerance range for abiotic factors
determines an organisms ability to survive.
 Interactions occur within abiotic
surroundings – eg large storms can
change the physical landscape and the
pH of soil and water.
Ecological Interactions between organisms
(biotic) and their environment (abiotic and
biotic)
Types of Interactions
 There
are several types of interactions
between species, referred to as:





competition
predator–prey relationships
parasitism
mutualism
commensalism.
Interactions in a living community
 Interactions
can involve members of the
same or of different species.
 Competition within and between species
occurs when resources are limited:


Intraspecific competition: within a species
Interspecific competition: between more than
one species.
 Competition
between populations in a
community is reduced when there is niche
separation.
 Competition
can be in the form of visible
fighting and threats or in a non-visible
form known as:
 ALLELOPATHY – Chemical inhibition – the
release of a chemical be a plant, which
prevents the germination or growth of
another plant species.
 Pine trees are renowned for this.
 Pheromones – are very important
chemicals used for non-competitive
communication between organisms,
usually to attract a mate.
Predator-Prey Relationships
 One
species (predator) kills another (prey)
 Carnivorous heterotrophs have:
 Structural,
physiological and behavioural
features assisting them to obtain food.
Eg. Spiders build webs, big cats have canine
teeth, cooperative hunting by dolphins.
 They have different strategies in obtaining
their prey. Eg Coral polyps capture their prey,
including fish, using the stinging cells on their
‘arms’ and a lion will stalk and then pounce,
surprise and chase it’s prey and use teeth and
claws to kill it.
Prey are not always caught
 Due
to structural, behavioural and
biochemical features.
 Structural:
camouflage- look like something
else to disguise and mimicry – look like
something that is not appetising.
 Behavioural: remaining still or playing dead,
keeping lookout and hiding, schooling –
safety in numbers.
 Biochemical: some animals eat plants which
makes them distasteful to others. These are
often brightly coloured to warn predators eg.
Monarch Butterfly.
Herbivore-Plant Relationships
 Most
herbivores are insects
 Plants cannot run away or hide from
herbivores so how do they defend
themselves?
 Horns,
spines, stinging hairs;
 Various plant species also produce
allelochemicals

Some of these chemicals include cyanide which can kill
or deform insects
Ecosystems Collaborative Task
Download diagrams from the student portal.
Use Bubbl.us.com to create your own ecosystem mind map –
to be done in pairs.
Use as many keywords as you can from the list below. Use the
diagrams as a guide to include examples where possible.
1.
2.
3.
•
•
•
•
•
•
•
4.
5.
Ecosystem
Community
Population
Habitat
Microhabitat
Niche
Autotrophs
•
•
•
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Heterotrophs
Decomposers
Detritivores
Biotic and Abiotic Factors
Competition
Predator–prey
Herbivore-plant
In a PowerPoint slide, insert one diagram.
Using the text box function, label your diagram with as many
of the keywords as possible (listed above).
Parasite-Host Relationships
 In
Animals:
 an
organism (the parasite) lives on or in
another kind (the host) and feeds on it,
typically without killing it, but:
 the host suffers various negative effects in this
relationship and only the parasite benefits.

Eg ticks and mammals
 It’s
estimated that parasites outnumber freeliving species by about four to one.
 EXOPARASITES – live ‘on/outside’ their host.

Eg. Fleas, ticks, leeches and fungi such as Tinea.
 ENDOPARASITES

– live ‘in’ their host.
Eg. Tapeworm and roundworm
Parasitoids
Are a varied group of organisms, mainly
small wasps and flies, that are like
parasites. (The suffix -oid means ‘like’.)
Parasitoids kill their hosts, which are usually
another kind of insect.
 They take some time to do this, unlike a
predator-prey relationship in which the
death of they prey is very quick.

Parasite-Host Relationships in Plants
 Two
kinds of parasite–host relationship
can be recognised,:
 Holoparasitism, in which the parasite is
totally dependent on the host plant for all
its nutrients.
Eg. Rafflesia - forms largest flower on earth
 Hemiparasitism, in which the parasite
obtains some nutrients, such as water and
minerals, from its host but makes some of
its own food through photosynthesis.
Eg. Mistletoe
Mutualism
A
prolonged association of two different
species in which both partners gain some
benefit.
 Eg.
Lichens consist of algae and fungi
 Trapezia crab and coral polyps
 Nitrogen fixing bacteria and certain plants
which cannot extract Nitrogen form the air.
Commensalism

(= ‘at the same table’) refers to the
situation in which one member gains
benefit and the other member neither
suffers harm nor gains apparent benefit.
 Eg.
Clown fish and Sea Anemones
Symbiosis
 Interactions
such as parasitism, mutualism
and commensalism are sometimes
grouped under the general term
symbiosis (= ‘living together’) - close
associations between two species that
have evolved over geological time.
Summary of Symbiotic Relationships
Interaction
Species 1
Species 2
Parasitism
parasite: benefits
host: harmed
Mutualism
species 1: benefits
species 2: benefits
Commensalism
species 1: benefits
species 2: neither
harm done nor
benefit gained
Natural Succession

In an ecosystem, changes to physical and
chemical features can cause a community to
change.

Succession - The natural replacement over time of
one community by another community with
different dominant species.


Primary succession: ecological succession occurring in an
area that was not previously colonised. Eg after a larval
flow creates a new plateau.
Secondary succession: establishment over time of
replacement communities in an area following an event
that removes the original community. Eg a bushfire
Pioneer Species




The first species to become established in a
‘new’ habitat.
can survive under harsh conditions .
adapted for dispersal and rapid
reproduction.
typically r-selected species.
Climax Community



Succession stops when a stable community
becomes established, with no further
change in the dominant species.
This stable community is known as
the climax community.
The climax community depends on the
physical features in the area (aspect,
altitude, temperature, rainfall and soil type)
Read example page 448