Chapter 3 Flashcards
adaptation
Any heritable behavioural,
morphological or physiological trait, evolved by
natural selection*, that maintains or increases
fitness of the organism in prevailing environmental
conditions
examples of adaptation
Opuntia polyacantha (plains pricklypear) is common in Western North
America, including the Canadian prairies:
1. Spines protect
against herbivores,
dissipate heat and
reflect radiation.
2. Succulent
stems store
water over dry
periods
3. CAM
photosynthesis
saves water
what are some of adaptation that North American beaver requires?
- Waterproof fur keeps the skin dry and warm
- tail acts as rudder and enables to warn other beavers
- teeth allow to cut wood for food, and build dams to allow winter survival
t/f: An adaptive trait to certain conditions can be a disadvantage
under different conditions
true
T/F: Warm and waterproof skin almost
led to extinction of beaver after Europeans arrived is an example of advantage of adaptation trait
false/ it is an example of disadvantage of adaptation
Trade-off
An adaptive response to one environmental constraint
may be a disadvantage under other circumstances, thus an organism cannot have it all.
what are some examples of trade-off?
- Waterproof fur of beavers almost lead to their
extinction. - Cacti tolerate drought, but are not competitive
under productive conditions.
T/F: based on evolution by natural selection Organisms are adapted
to the environment they live in,
otherwise they would not survive
True
T/F: Species’ adaptation enables predictions about their occurrence
T
T/F: Adaptation to harsh conditions usually means that the species is
less competitive under more productive conditions
True
Fitness
Proportionate contribution of
an individual to future generations.
Fitness increases with the number of
surviving progeny
T/F: Intraspecific
genetic variation
can be large
True
what are some of the examples of genetic variation within one species as a result artificial selection by humans?
Brassica Oleracea: wild cabbage, Kale, Red cabbage, Cauliflower.
t/f: Local adaptations within a species
result in ecotypes
true
what are some different affects of natural selection?
- Directional
- Stabilizing
- Disruptive
T/F: Hand-raised blackbirds from urban populations
tolerate more stress than those of rural populations.
The difference is genetic
True
Trade-off mitigation
The advantage of great nesting sites under highway
bridges is dampened by the disadvantage of an increased risk of death by
cars. This trade-off can be mitigated by increasing agility (shorter wings)
convergent evolution
a result of adaptation to
similar environmental conditions
T/F: Cacti (America) and Euphorbs (Africa) represent convergent
evolution to similar environmental conditions
True
Divergent evolution
a result of adaptation to
different environmental conditions
Allen’s rule
In homeothermic animals that are adapted to cold climates
the body surface area-to-volume ratio is lower (shorter
limbs, smaller bodily appendages) than in animals adapted
to warm climates
Adaptive Radiation
Evolution of different species from a common
ancestor, all adapted to distinct features of the
environment, such as food items or habitat. Often found on islands, where a few individuals of
an newly arriving species evolve to several species,
filling the different available ecological niches
