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Lecture

Bio lab 6 notes Dec 2 2009

by OC4

Department
Biology
Course Code
BIO120H1
Professor
Ingrid L.Stefanovic

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Bio lab 6
Phenotypies plasticity:
Phenotype t the out appearance t importanc ein the process of evolution
Evolution in population depends on phenotypic traits being passed down from generation to generation
t howver, is genotype the basic that cause the change
The genotype is the complete genetic constitution of an organism
When the phenotype is change in a population, it may results from the interaction between genotype
and the environment
Alternation of the phenotyoe in individual is called acclimation.
Note that it[s not a adapation, adaptation is the term used for population not for individual!
Phenotypic plasticity is the concept used by biologists to describe the degree to which a given genotype
can alter its phenotypoc expression in order to acclimate to irs surroundings
Reaction norm: the relationship between the environment and the trait in question
Cost and limits:
Who can[t all the traits be phenptypically plastic?
1st, insufficient genetic variation exists for the evolution of plasticity to occur.
Even if the genetic variation is sufficient, costs and limits may resultin a selective pressure against a trait
evolving phenotypic plasticity. Eg. Energy cost and stuff
Limitation:
To be accurate t if sense the environment wrong t may lead to death
Time consuming t take long time to change t the greater the change, the longer the time
Generalists and specialists:
Generalists: species with high phenotypic plasticity are commonly considered as ~
Specialists: are populations with low acclimation potential, but can maximally expolit a single set of
environmental conditions
Stable environment t specialists better
Heterogeneous environment t generalists better
Plastic response in plants t in plants, phytochrome accept the light, when receive different lights with
different wavelengths, it activate different set of genes and reponse differently
We use compound microscope here
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