Abiotic Factors Part I Adaptations to environmental conditions

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Abiotic FactorsPart I Adaptations to
environmental conditions
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All organisms are limited in their distribution
by abiotic factors

• Each organism has a range of conditions within
  which it can survive
• We call this an animals niche
• If conditions are outside this range the organism
  cannot survive

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Organisms occupy a wide rage of conditions

• Arctic and Antarctic (Temp lt - 40 C)
• Deserts and tropics (Temp gt40 C)
• Extreme conditions in thermal vents support
  extensive biological communities
• Water temperature 400 C
• Extreme pressure prevents boiling
• No light

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Niche

• The range of conditions to which a species is
  adapted is called its ecological niche
• Different species will evolve different
  adaptations depending on the environmental
  conditions they face
• As a result, different species will tolerate
  different ranges of environmental conditions
  depending on their evolutionary history

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Species coexist

• Because they are adapted to different conditions
• They occupy different niches
• No one species dominates everywhere because
  conditions vary from place to pace

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Fundamental Niche

• We sometimes call the range of conditions to
  which a species is adapted is called its
  fundamental niche to distinguish from the range
  of conditions actually occupied
• The realized niche

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Realized Niche

• The realized niche is often smaller the
  fundamental niche
• Because as organisms approach the extremes of
  their tolerances, they may be able to tolerate
  the conditions but they are often inferior
  competitors

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Niche
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Moisture and temperature

• Moisture and temperature are two factors that
  play an important roles in ecosystems

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Moisture gradients

• Amphibians are distributed along moisture
  gradients

Increasing Moisture Gradient
Ephemeral Pool Semi-permanent Wetland
Permanent Wetland Lake
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Moisture gradients
Increasing Moisture Gradient
Ephemeral Pool Semi-permanent Wetland
Permanent Wetland Lake
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Moisture gradients

• Wood frogs
• Live in ephemeral pools
• Need to breed and develop quickly
• Ephemeral pools lack predators like fish
• Woods frogs grow quickly in predator-free
  environments because they dont spend energy on
  predator avoidance

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Moisture gradients

• Green frogs and Bull frogs live in lakes
• Predators like fish require tadpoles to devote
  time and energy to avoiding predators
• Growth is slower
• Dont become adults until their second summer

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Moisture gradients
Ephemeral Pool Semi-permanent Wetland
Permanent Wetland Lake

• The period of water availability and the
  resulting differences in predator communities
  determine where amphibian species occur

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Plant gradients

• Plants are distributed along moisture and water
  depth gradients
• Each species has a different range of conditions
  within which it can live

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Adaptations to the abiotic Environment

• All species face similar challenges
• Different species have evolved very different
  solutions to the same environmental challenges
• Big brown bats, black-capped chickadees and
  yellow warblers are all adapted to survive cold
  Canadian winters
• But their solutions to the same challenge are
  very different

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Big brown bats

• Insectivore
• Endothermic
• Hibernate underground
• Heterothermic

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Yellow warblers

• Insectivorous endothemic like the big brown bat
  
• But have evolved a different solution
• Migrate south
• (lack the ability to hibernatehomeothermic)

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Black-capped chickadees

• Stay and remain active
• Switch to eating seeds
• Store food

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Adaptations can involve

• Behavioural, physiological and morphological
  adaptations

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Behavioural adaptations

• Migration e.g., bats, birds, insects
• Diet shifts e.g., birds switching from insects
  to seeds

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Physiological adaptations

• Torpor (hibernation, daily torpor)
• Extreme freeze tolerance
• Wood frogs, red bats

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Morphology

• Body size
• Feathers and fur

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Different categories are not mutually exclusive

• Most organisms that are cold tolerant have
  adaptations involving multiple levels of
  organization
• e.g., hibernating bats

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Hibernation

• Behaviour migration
• Physiology torpor
• Morphology roosting mechanism

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Cold tolerance is not the only abiotic factor
organisms must deal with

• Temperature
• Humidity
• Nutrient levels
• Disturbance frequency
• Etc.

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A niche is an n-dimensional hyper-volume not a
two dimensional graph