Transcript Chp 13 Adaptations - AdventuresinScienceEducation

V.C.E. Biology Unit 2
Environmental factors and adaptations
Environmental Factors
 Tolerance Range – the range of a specific
environmental factor, such as pH that an
organism can survive in.
 Limiting Factors – a requirement of an
organism that is in short supply, eg. Nest
sites.
 Distribution – these two concepts limit the
places where an organism can be found.
 Adaptation – unless it changes itself in some
way to survive within broader ranges or with
less of a limiting factor.
Structural Adaptations
 Structural adaptations are special
body parts of an organism that help it to
survive in its natural habitat, for
example, its skin color, shape and body
covering.
 For example, xerophytes – arid land
plants, have thicker waxy cuticles, hairs
that cover the leaves, fewer stomata
that are sunken in pits, reduced leaf
size and orient their leaves away from
the sun. All this is done to avoid water
loss.
Physiological Adaptations
 Physiological adaptations are systems
present in an organism that allow it to perform
certain biochemistry reactions.
 For example: making venom, secreting slime,
or being able to keep a constant body
temperature.
Behavioural Adaptations
 Behavioural adaptations are special ways a
particular organism behaves to survive in its
natural habitat
 For example, many burrowing animals huddle
together under ground during winter to share
body heat and keep warm.
Living in Water
 pH – the pH range of Australian inland waters
is about 6 – 9. Organisms must be able to
tolerate this range.
 Temperature – this fluctuates from summer to
winter, but in Australia our organisms rarely
need to deal with frozen water.
 Light – Blue light is able to penetrate up to
20m in clear water, but the other wavelengths
diminish much earlier, limiting the spread of
plants in aquatic environments.
Marine Environments
 Coastal marine environments show large
daily variations with the movement of the
tides determining the availability of food,
shelter, water, sunlight etc.
 Other marine environments are also ever
changing with the availability of food and
water temperature changing seasonally and
even daily, but the ranges tend to be less
severe.
Terrestrial Environments
 There are many harsh environments on land.
Organisms need to be able to tolerate wide
variations in water availability, temperature,
light availability, soil conditions, wind
conditions and the seasonal availability of
food.
 They have a broad range of adaptations to
achieve this.
Surviving Disturbances
 Australian organisms need to be able to cope
with broad scale disturbances to their
environment.
 Flood
 Drought
 Fire – there are some special adaptations in
plants with epicormic buds, lignotubers,
particularly tough seeds, but this is much
harder for animals.