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Summary - Adaptation Physiology of Animals
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Summary of course: Adaptation Physiology of Animals
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GijsGov
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Introduction of definitions:Evolution is like tinkering; improvement by random chances (Jacob Francois)
Adaptation = a heritable physical or behavioral trait that serves a specific function and
improves an organism’s fitness or survival
-Adaptations are non-reversible
-Adaptations could be considered as the degree of environmental-specificity
-To determine whether it is an adaptation (IF, FC?) → Inheritable?, functional?, fitness or
survival rate higher? current function still applied?
-The Mechanism of an adaptation and Adaptive significance must be studied separately,
since they do not imply each other
Insulation = energy conservation
Acclimatisation = (‘fast’, i.e. within the lifespan of an organism)
Acclimation = the response to experimental conditions; it tells us about the capacity of an
organism to handle disturbances, within the bandwidth of the genotype and thus its
evolutionary capacity (and success).
Example: A camel is adapted to desert life, a human being can acclimatise to desert
conditions, or we can force a mouse to acclimate to desert conditions (called acclimation)
§1 Evolution, adaption and ecophysiology
Homologous organs = same ancestor and therefore same anatomy, different function
Analogous organs = different ancestors and therefore different anatomy, same function
Non-Adaptations
1- Genetic Variation due to Genetic drift = the change in frequency of an existing gene
variant in the population due to random chance
2- Exaptation = Shift in the function of a trait during evolution
3- Vestigiality = partial or complete loss of a function of a trait compared to ancestors;
non-functional anymore
4- Spandrel = A byproduct, formed due to adaptation and natural selection of another
characteristic. These byproducts of adaptations have no real relative advantage to survival
but may later co-opt for a secondary utility
,5- Acclimatization, flexibility and learning
Adaptations
The process of natural selection is the only force driving adaptations
Natural selection = the increase in frequency of genes that produce phenotypes that raise
the likelihood that animals have a higher fitness and survival rate → perform better in their
environment
4 Conditions of natural selection (HO FR)
1. Heritance, traits need to be heritable
2. Organisms must have different characteristics (variation) caused by mutations and
recombinations
3. Fitness, organisms with these traits must show a higher fitness (adaptation) and
survival rate
4. Reproduction, organisms must reproduce to establish offspring
Adaptive radiation = a process in which organisms diversify rapidly driven by exposure to
different environmental niches
Co-adaptation = New features that evolve must integrate well with the rest of the bodily
structure and organization
From the contributors to Darwins idea’s remember the following things:
Charles Darwin explained adaptation by using natural selection, a materialistic approach
● Erasmus Darwin → Idea that organisms change over time
● Hutton → Gradualism= The slow cumulative processes occurring every day which
explain geology
● Lamarck →
Correct theory: Inheritance; ‘’acquired changes are passed onto offspring’’
Wrong theory: (1) Believed that organisms acquire or defuse traits during their
lifetime and that these traits could be passed on to their progeny. In other words: Species
developed independently and without a common ancestor. (2) Spiritual approach by thinking
that organisms are acquiring changes in features if it helps them to live more successfully.
● Robert Malthus → Struggle for resources, Population size is limited by resources
● Cuvier → Species extinct
, ● Lyell (Wrote Principles of geology which Darwin obtained from the captain of The
Beagle → Lyell came up with Actualism= Gradual geological processes are still
occuring, just like in the past.
● Wallace → transmutation and natural selection
Darwin's findings review
• Individual organisms in nature differ from one another. Some of this variation is
inherited.
• Organisms in nature produce more offspring than can survive, and many of these
offspring do not reproduce.
• Because more organisms are produced than can survive, members of each species must
compete for limited resources.
• Because each organism is unique, each has different advantages and disadvantages in
the struggle for existence.
• Individuals best suited to their environment survive and reproduce successfully – passing
their traits to their offspring.
• Over long periods, natural selection causes changes that may eventually lead to new
species. Species change over time.
• Species alive today have descended with modifications from species that lived in the
past.
• All organisms on earth are united into a single tree of life by common descent.
Methods of studying adaptations
● Laboratory experiments → artificial selection
● Single generation studies of individual population
● Creation of variation for study → knocking out genes or gene silencing (RNAi)
● Genetic structures of natural populations study→ Genetic clines (change of
alle-frequency along an environmental gradient)
● Phylogenetic study → Family tree composition
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