Unifying themes in physiology
-the physiological state of an animal is part of its phenotype, which arises as the product of the genetic make-up (genotype) and its interaction with its environment
-Genotype is the product of evolutionary change in a population of organisms over many g
4. Physiological processes are usually regulated: Phenotype, Genotype and the Environment
Phenotype= Genotype+environment
Genotype
genetic makeup
Phenotype
morphology, biochemistry, physiology, and behavior
Phenotypic plasticity
single genotype generates more than one phenotype depending on the environmental conditions
-genotype working with environment
-genotype is fixed
-phenotype is NOT fixed
-may be reversible and irreversible
-occurs within a lifetime
Mod butterflies example with Phenotypic plasticity
-when born in the spring they have more melanin which means that they are darker
Proximate: melanin
Ultimate cause: ectothermic so in the spring it is colder since they have to absorb more heat
Whiter in the summer
-there are multiple phenotypes
Factors influencing phenotype
the environment that the animal lives in affects development, biochemicty, physiology, morphology, and behavior
Can affect the reproductive success of the animal
Environment with random processes
with the fires, some foxes can survive
Environment and Natural Selection
some animals will survive better due to their environment and physiological advantages
Phenotypic plasticity in endurance in humans (Acclimatization)
the ex) is men being able to run for a prolong period of time in a certain temperature more when they have higher heat exposure
The men displayed: (mechanistic changes)
-increased rate of sweat secretion
-sweat glands can maintain high rates of sweat secr
Phenotypic Plasticity: can be irreversible or reversible
Irreversible: you will be stuck with that phenotype
-once the environment affects genotype and makes the phenotype fixed
-aka Developmental plasticity (example is Daphnia -water fleas: the phenotype changes whether the flea is raised in an environment wit
Acclimation (Under reversible conditions)
This change happens under laboratory conditions
acclimatization (Under reversible conditions)
natural environment
Polyphenism v. Reaction norm
Polyphenism: with he example of Daphnia, the tail will be 10 mm if there is a predator in the environment. There is no inbetween with the 2 mm and the 10mm.
Reaction norm: Varies a lot with its environment
-the range of phenotypes that can be produced by
Why have a plastic phenotype?
-there are seasonal changes in food supply (more food in summer than in the winter)
-seasonal changes in temperature, and activity variation (like hibernation)
-we know that environments change rapidly
Know these 3 differences below
okay boss
Causes of physiological diversity: Adaptation
Adaptation: evolutionary occurs over generations, genetic
-the change of phenotype occurring by process of natural selection
-adaptations are traits that evolved to confer fitness in response to a particular environmental feature
-a lot of genetic variati
Causes of physiological diversity: Acclimation
Chronic, occurs during a lifetime, non-genetic
-phenotypic plasticity in response to a change in one specific physiological or biological characteristic
-Laboratory, experimentally determined: Acclimation to temp determined by holding animals under identi
Causes of Physiological diversity: Acclimatization
-Chronic, occurs during a lifetime, non-genetic
-Phenotypic plasticity during variation in natural environmental characteristic (ex Winter v Summer Acclimatization)
The Concept of Time: Environmental Stressor
Short-term modulation (acute response): sec to minutes
Acclimation/ acclimatization (days to weeks)
Adaptation (many generations)
Adapated populations have some degree of ..
phenotypic plasticity
-depends on how evolved they are
Not All Differences are Adaptations
-random changes in the frequency of the genotypes over time (genetic drift)
-independent of adaptive evolution
-most common in small populations
Example: forest fire resulting in founder effect so having a few individuals left over with genetic variation
preadaptation or exaptation
animals have traits that were selected for by the environment natural selection bc of their performance advantage they gave BEFORE their current environment they are in
-the current environment they are in takes advantage of that trait
-adapatation happen