Transcript document

Welcome to
Unit 2 Biology
Organisms and their
Environment
Area of Study 1 –
Adaptations of Organisms
Chapter 9
Habitats, environment and survival.
Key Knowledge
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Develop a knowledge and understanding of habitats and
the environments that exist in them.
Identify major factors that produce the environments of
various habitats and distinguish between biotic and
abiotic factors.
Give examples of structural adaptations that equip
organisms for survival under particular environmental
conditions.
Explore technologies used to record environmental factors
and track distribution of species within their habitat.
What is a habitat?
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The location or place where an organism lives at any given
time is known as its habitat.
The habitats of different kinds of organisms vary greatly.
Many habitats can be described in general terms as being
- Terrestrial (e.g. deserts, grasslands, forests etc) or
- Aquatic, which includes freshwater, marine and
estuarine.
Members of one species do not live in isolation in a
habitat.
Members of the different species that share one habitat
form the living community of the habitat.
Microhabitats
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In reality, many organisms share one habitat.
The way that they accomplish this, without becoming
overcrowded is to occupy their own individual
microhabitat.
A microhabitat is a more localised or specialised part of a
general habitat.
For example, in a freshwater pond, some organisms may
occupy the soft sediment at the bottom, while others may
live among the aquatic plants. These are two different of
many microhabitats
More on habitats
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The habitat provides the resources that are needed for the
life of a particular organism.
For a typical animal, these include water, food, shelter,
nesting and breeding sites.
Habitats are not uniform.
For example animal may feed in one part of a habitat,
while it nests in another part of the habitat, and finds
water in yet another part.
Range: the distribution
of habitats
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The geographic area that encloses all the habitats where
the species lives denotes the range or distribution map of
the species.
Over time, the range of any species may increase or
decrease, depending on its needs.
Many of our native Australian species have a shrinking
range, due to increased human population or introduced
species.
Conversely, the range of many introduced species is
increasing.
Range
Moving between habitats
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There are often reasons for animals to move between
habitats.
Animals that do this are said to be migratory.
Migrations are typically associated with access to food
resources or breeding sites or to movement from
unfavorable seasonal conditions, such as moving from
extreme cold.
Migration
Species with an annual migration of their
life cycle include:
- short-tailed shearwaters or muttonbirds
- humpback whales
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Species with a once a lifetime migration
in their life cycle include:
- short-finned eels
- bogong moths
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Diapause
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Some animals cope with seasonal lows using the state of
diapause.
This is where an animal moves into ‘energy control mode’
during times of the year that are unfavourable.
This usually includes being in a non-feeding low energy
state.
This stage is similar to that known as hibernation.
Technology
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How does technology fit into habitats???
It is an important tool in the study of habitats,
particularly those that cover large areas.
It is more accurate than the old fashioned one person in
the field with a notebook.
Different uses
for technology
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Monitoring vegetation is large scale habitats
Conventional techniques, such as aerial photography is
useful in some ways, but has the downfall of being unable
to distinguish different species of plants which may be
crucial to the survival of a certain species.
The use of remote sensing on an orbiting satellite, such as
Landsat is able to achieve this by detecting ‘signatures’
present in the vegetation of concern.
Monitoring animal movements
within habitats
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Some animals move over very large distances within their
habitat.
Several radio tracking or telemetry techniques are in
current use, but these devices are generally restricted to
larger animals with sufficient size to carry the tracking
device.
Monitoring animal movements
within habitats
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The oldest technique for tracking terrestrial animals is
very high frequency (VHF) radio tracking, that was
introduced in 1963. This involved a device being built into
a collar.
Monitoring animal movements
within habitats
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Later, satellite tracking became available. This technology
enables animals to be tracked both across large areas of
land and in the ocean. Unlike VHF tracking, satellite
tracking does not require people to be in the tracking area.
Satellite tracking
Monitoring animal movements
within habitats
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A relatively new form of tracking, called a pop off archival
tag (PAT), which is Used for aquatic animals.
This type of tag not only provides migratory information,
but also information on the environment.
These tags are programmed to collect data every few
minutes over a given period of time. At the end of that
time, the tag detaches, or ‘pops off’ the animal and floats
to the surface.
Niches
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The term ‘niche’ refers to the ‘way of life of a species’. Some
other short definitions of a niche include:
- the role or profession of a species in a community
- the way of life of an organism
- the status or role of an organism in its habitat.
The many species living in a biological community have
different ways of lives or niches.
For each animal species, a description of its niche might
include where it lives and feeds, what it eats, when it feeds
and the environmental conditions it tolerates.
Structural features equip various species to occupy
different niches in a habitat e.g. beak length.
Niche overlap
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Because they are not in direct competition for the same
food and space resources at the same time, different
species in a community in a natural habitat typically have
either zero or a low degree of niche overlap.
In general, two or more different species cannot occupy the
same niche in the same community for an extended period
of time. They will be in direct competition which could
possibly result in a depletion of resources, which could be
ultimately detrimental to both species.
Environment
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The physical, chemical and biological conditions that exist
in the habitat make up the environment.
An environment may also be described as:
A collective term for the conditions in which an organism
lives
The sum total of external influences acting on an
organism
The external surroundings in which an organism lives
and which are influenced by abiotic and biotic factors.
Environmental factors
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The various factors that produce the particular conditions
in a habitat are called environmental factors.
Biotic or living factors relate to other living organisms in
the environment and include factors such as the presence
of predators, parasites and competition between members
of one species.
Abiotic are non living factors relating to aspects of soil,
water, light, shelter, temperature etc.
These are some of the
biotic (red) and
abiotic (blue) factors
that contribute to
the environment of
the black-necked
stork.
Environmental factors
Comparing air and sea
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Air and sea water have very different properties, and in
turn, terrestrial and marine environments have very
different environments.
These differences directly influence the animals that have
evolved in each of these environments, resulting in
significant structural and physiological differences
between terrestrial and marine organisms.
Describing environmental
conditions
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An environment can be described in qualitative terms,
such as ‘warm and humid’ where ‘warm’ refers to the
air temperature and ‘humid’ refers to the water vapour
content of the air.
An environment may also be described in quantitative
terms where a numeric value is stated, such as, ‘the air
temperature is 23°c’.
When scientists measure environmental factors in a
habitat, they usually express their findings in
quantitative term. Some of the devices are shown on
the next slide.
Comparing habitats
Tolerance range
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The distribution map of each species is affected by
environmental factors. Every organism has a tolerance
range for environmental factors, such as temperature,
desiccation (drying out), oxygen concentration, light
exposure and so on.
A tolerance limit identifies the range in which an
animal can survive that particular condition.
If an environmental factor has a value above or below
the animals tolerance limits, that organism will not
survive if it cannot escape. Tolerance ranges differ for
species and are influenced by structural, physiological
and behavioral factors of an organism.
Tolerance range
Who survives where?
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The kinds of organisms found in various habitats are
determined by their ability to survive in the prevailing
environmental conditions.
Organisms have both upper and lower limits.
Any condition which approaches or exceeds the limits of
tolerance for an organism is said to be a limiting factor for
that organism.