124 Types of Adaptations
CL N AS OT SR F OO OR M US E
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Key Idea: An adaptation is any heritable trait that equips an organism for its functional role in the environment (its niche). An adaptation is any heritable characteristic (trait) that equips an organism for its niche, enhancing its exploitation of the environment and contributing to its survival and
successful reproduction (fitness). Adaptations may be structural (morphological), physiological, or behavioural. The adaptations of species are the result of their evolution in particular environments. Traits that are not helpful to survival and reproduction will not be favoured and will be lost.
Kangaroo adaptations
PR E O V N IE LY W
The red kangaroo (below) is the largest living marsupial. It is powerfully built and adapted for high speed, hopping locomotion, and survival in dry habitats. They are active mainly at night, roaming in small groups over a home range of 8 km2 (or larger when resources are scarce). Dominant males establish exclusive mating rights by boxing.
Behavioural adaptations
Physical adaptations
` Licking the pads of the front paws assists in
` Robust, high crowned
cooling by evaporation.
molar teeth. The molars are replaced as they wear down as an adaptation to a diet of abrasive grass.
` Kangaroos often live in groups (mobs) which helps increase protection from predators.
` Kangaroos are active during the cooler parts
` Dense, fine fur provides
of the day and seek shade in the hottest parts of the day.
insulation against excessive heat loss or gain. Fur is reflective, especially on the flanks.
` Foot thumping is used to signal danger to others in the mob.
` Fighting between males involves both wrestling
` Hind limbs heavily
Physiological adaptations
` Long foot bones help
muscled and high speed hopping is extremely energy efficient. Energy is stored in the tendons and elastic recoil is used to power the next jump.
with the forearms and kicking with the hind limbs, using the tail as a balance.
` Females may breed all year. They may have
balance. The second and third digits are fused and the fourth is much larger and longer than the others.
a joey at heel, one in the pouch, and a dormant embryo ready to replace the pouch offspring as soon as it leaves. In unfavourable conditions, embryos can be reabsorbed by the mother if resources are scarce.
` Stout, tapering tail acts
as a fifth limb in slow fivepoint movement. In bipedal hopping the tail acts as a counterweight.
` Thin skin well supplied with blood vessels,
especially on the forelimbs, to assist heat loss by evaporation.
` Females are able to produce two different
kinds of milk simultaneously for the newborn and the older joey still in the pouch.
1. (a) What is an adaptation?
(b) How do adaptations contribute to an organism's fitness?
A-3
CL
3. Describe two physical adaptations for locomotion in red kangaroos:
N AS OT SR F OO OR M US E
2. Describe two behavioural adaptations for protection against predators in red kangaroos:
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