abiotic factors in biology
Post on 13-May-2017
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Abiotic Factors
• Physical and chemical properties
of the enviroment – temperature,
water and humidity, light
• Subgroup of ecological factors
Temperature
• Considering the body temperature, animals
can be:
– Poikilothermic or ectothermic
– Homeothermic or endothermic
– Heterothermic
Poikilothermic or ectothermic animals
• Variable body temperature – depends on the
enviroment
• Often change body temperature
• Fish, reptiles, invertabrates,
amphibians
Homeothermic or endothermicanimals
• Constant body temperature
• Birds (38-42°C) and mammals (36.9°C)
• To mentain their body temperature they have:
– Feathers and hair
– Fat tissue
– Developed cardiovascular
system
Heterothermic
• Depending on their needs, they can turn on
endothermy or ectothermy
• Changes occur on a daily or on an annual basis
• Some bugs, birds and
bats
Diapauses
• State of animal dormancy, in which an
organism uses its fat reserves to survive
• Amphibians, reptiles and insects
Aestivation
• State of animal dormancy, characterized by
inactivity and a lowered metabolic rate
• Used to survive high temperatures and
drought• Snails, amphibians and
rodents• http://www.youtube.com/watch?v=Fd_uqpAE
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Moulting
• Change of feathers by birds or change of hair
by mammals
• Preparation for new
weather conditions
Hibernation
• State of animal dormancy, characterized by
inactivity, lowered body temperature and
lowered metabolic rate
• Hedgehogs, dormouses,
raccoons, bats and
some marsupials
Plant Dormancy
• Seeds – dormant until temperature, humidity
and light are ”just right”
• Trees:
– deciduous plants lose their leaves
– evergreens stop all new growth
Migrations
• Some animals avoid cold weather by
migrationg to warmer areas
• Whales, bats,
some fish,
butterflies and
some birds
Body Temperature
• Affects basal metabolism – bigger animals
have slower metabolism
• Extreme values affect enzymes which controll
important chemical processes within an
organism
Water and humidity - Xerophytes
• Plants which adapted to low water and
humidity enviroments by growing small hairs
on their leaves (prickly saltwort) or by
covering them with wax (laurel)
• Olive
Mesophytes
• Transitional form from xenophytes to
hygrophytes
• Most decidous
trees – oak, beech
Hygrophytes
• Inhabit moist woods and meadows
• Leaves with
many stomata
• Canes, sedges,
spearworts
Hydrophytes
• Plants whose vegetational parts live
underwater, float on water or are partially
submerged in water
• Rice, lotus
Animal adaptations to water loss
• Bugs – chitin shell• Reptiles – scales• Desert camel:– thick hair – sun protection– hump – fat tissue, can contain up to 49 liters of
water– Can drink 90 liters of water in 10 minutes
Light
• Diurnal animals – active during daylight
– Cheetahs, snakes
• Nocturnal animals – active at night
– Bats, owls
Light
• Olms are fully adapted to life in absolute darkness– Stunted eyes– No pigment
Echolocation
• ”Looking with ears”
• Sonar principle
• Bats emit sound signals which bounce from
their surroundings and enter their ears, and
this is how they evaluate distance
• http://www.youtube.com/watch?v=p08Y0oRA
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