ANIMAL ADAPTATION PHSIOLOGY
,Contents
Lecture 1: Adaptation and evolution:...........................................................2
Lecture 2: Adaptation to cold environments................................................4
Lecture 3: Adaptation and energy metabolism..........................................13
Hibernation slides practical:.......................................................................19
Lecture fish osmoregulation:......................................................................22
Lecture: Growth and moulting in crustaceans............................................27
Lecture osmoregulation in crustaceans:....................................................39
1
,Lecture 1: Adaptation and evolution:
Adaptation:
-An adaptation is a feature that improves function, or is otherwise advantageous to an individual.
-These traits are well fitted to their purpose and therefore are common in a population.
-This can be expressed in several ways, for instance in physiological responses, behaviour, physical
features, or structurally altered proteins adapted to function best at a given environmental condition
Evolution and adaptation Darwinism in a nutshell
Natural selection:
The process that drives evolution by favouring beneficial
adaptations. Individuals differ, and some differences
affecting survival and reproduction can be inherited.
Adaptations are a result of natural selection.
During the “struggle for resources”, the fittest individuals
will survive (i.e. the frequency of the beneficial gene in the
population increases) and reproduce. This is called
Survival of the fittest.
The four conditions needed for natural selection:
1. Time. Natural selection happens over many
generations.
Small changes accumulate as advantageous traits become more common.
2.There is a variation in the population (grey and white mouses)
3.Traits must be heritable
4.There has to be a difference in fitness differential reproductive success (some individuals have
more offsprings),
Survival of the fittest: Darwin’s focus on adaptation:
Fitness: an individual’s ability to survive and reproduce.
Adaptation: an inherited trait that increases survival and reproductive success.
Individuals with beneficial adaptations pass these traits to their offspring.
Understanding adaptations helps explain how evolution occurs.
Darwin’s theory of evolution
The unequal ability of individuals to survive and reproduce leads to a gradual change in a
population, with favourable characteristics (adaptations) accumulating over generations by
natural selection”
2
, • New species evolve
-Not all traits are adaptations, because many traits do not increase fitness or are not made for this
specific function
To be a adaptation, the trait has to be:
- Is the trait heritable?
- Is it a functional trait?
- Does it increase fitness?
- Did this trait arise for its current function?
Non-adaptations and related concepts
Not all traits in organisms are adaptations produced by natural selection.
Variation
Some genetic differences between individuals do not affect survival or reproduction. These neutral
traits are maintained by mutation and genetic drift, not by natural selection. Like Color of fur of
housecats
Vestigiality
Vestigial structures are inherited remnants of traits that were functional in ancestors but have lost
most or all of their function because environments and selective pressures changed.
Example: reduced legs in whales or wings in penguins.
Exaptation
An exaptation is a trait that evolved for one function but later became useful for another function
when selective pressures changed.
Example: bird feathers originally evolved for insulation but later became useful for flight.
Spandrels
A spandrel is a byproduct of another adaptation that was not directly selected for survival. It may
have no initial advantage, but it can sometimes later gain a secondary function.
Acclimatization, flexibility, and learning
These are changes within an individual’s lifetime and are not inherited:
Acclimatization: short-term physiological adjustments to environmental changes (hours to
weeks).
Flexibility: the ability of an organism to live in different habitats.
Learning: behavioral improvements based on experience.
Note: the ability to acclimatize can be an adaptation, but the acclimatization itself is not inherited.
Considering adaptations
3
,Contents
Lecture 1: Adaptation and evolution:...........................................................2
Lecture 2: Adaptation to cold environments................................................4
Lecture 3: Adaptation and energy metabolism..........................................13
Hibernation slides practical:.......................................................................19
Lecture fish osmoregulation:......................................................................22
Lecture: Growth and moulting in crustaceans............................................27
Lecture osmoregulation in crustaceans:....................................................39
1
,Lecture 1: Adaptation and evolution:
Adaptation:
-An adaptation is a feature that improves function, or is otherwise advantageous to an individual.
-These traits are well fitted to their purpose and therefore are common in a population.
-This can be expressed in several ways, for instance in physiological responses, behaviour, physical
features, or structurally altered proteins adapted to function best at a given environmental condition
Evolution and adaptation Darwinism in a nutshell
Natural selection:
The process that drives evolution by favouring beneficial
adaptations. Individuals differ, and some differences
affecting survival and reproduction can be inherited.
Adaptations are a result of natural selection.
During the “struggle for resources”, the fittest individuals
will survive (i.e. the frequency of the beneficial gene in the
population increases) and reproduce. This is called
Survival of the fittest.
The four conditions needed for natural selection:
1. Time. Natural selection happens over many
generations.
Small changes accumulate as advantageous traits become more common.
2.There is a variation in the population (grey and white mouses)
3.Traits must be heritable
4.There has to be a difference in fitness differential reproductive success (some individuals have
more offsprings),
Survival of the fittest: Darwin’s focus on adaptation:
Fitness: an individual’s ability to survive and reproduce.
Adaptation: an inherited trait that increases survival and reproductive success.
Individuals with beneficial adaptations pass these traits to their offspring.
Understanding adaptations helps explain how evolution occurs.
Darwin’s theory of evolution
The unequal ability of individuals to survive and reproduce leads to a gradual change in a
population, with favourable characteristics (adaptations) accumulating over generations by
natural selection”
2
, • New species evolve
-Not all traits are adaptations, because many traits do not increase fitness or are not made for this
specific function
To be a adaptation, the trait has to be:
- Is the trait heritable?
- Is it a functional trait?
- Does it increase fitness?
- Did this trait arise for its current function?
Non-adaptations and related concepts
Not all traits in organisms are adaptations produced by natural selection.
Variation
Some genetic differences between individuals do not affect survival or reproduction. These neutral
traits are maintained by mutation and genetic drift, not by natural selection. Like Color of fur of
housecats
Vestigiality
Vestigial structures are inherited remnants of traits that were functional in ancestors but have lost
most or all of their function because environments and selective pressures changed.
Example: reduced legs in whales or wings in penguins.
Exaptation
An exaptation is a trait that evolved for one function but later became useful for another function
when selective pressures changed.
Example: bird feathers originally evolved for insulation but later became useful for flight.
Spandrels
A spandrel is a byproduct of another adaptation that was not directly selected for survival. It may
have no initial advantage, but it can sometimes later gain a secondary function.
Acclimatization, flexibility, and learning
These are changes within an individual’s lifetime and are not inherited:
Acclimatization: short-term physiological adjustments to environmental changes (hours to
weeks).
Flexibility: the ability of an organism to live in different habitats.
Learning: behavioral improvements based on experience.
Note: the ability to acclimatize can be an adaptation, but the acclimatization itself is not inherited.
Considering adaptations
3
