BIO120H1 Lecture Notes - Lecture 12: Mendelian Inheritance, Mitosis, Meiosis

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Published on 12 Nov 2011
School
UTSG
Department
Biology
Course
BIO120H1
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of 2
Lecture 12: Introduction to evolutionary biology
Assumed background knowledge
Ÿ Mendelian genetics
Ÿ Inheritance
Ÿ Structure of DNA
Ÿ Mitosis & Meiosis
Ÿ Chromosomes
Levels of biological organization
Ÿ MoleculesàcellsàorganismsàpopulationàCommunitiesàEcosystems
Question in evolutionary biology
Ÿ Scope of question
Small questions: answering small tractable questions can help contribute towards
solving a big question.
Large question: unlikely to be answered by one experiment; required multiple
lines of evidence (ex. Why did sex evolve? Why is most biodiversity in the tropics?)
Ÿ Types of question
How questions: involve determine the physiological or genetic mechanisms
responsible for aspects of a trait
Why question: involve determine the ecological function and adaptive significance
of a trait
Approaches used in evolutionary biology
Ÿ Observational: describe and quantify
Ÿ Theoretical: develop models-verbal ,graphical, mathematical
Ÿ Comparative: obtain same data from many species. Compare with others.
Ÿ Experimental: manipulate a system to address a specific hypothesis; requires an
experimental design and statistical analysis
Important assumptions about evolution verified by scientific study
Ÿ Organisms on earth have changed through time
Ÿ The changes are gradual not instantaneous
Ÿ Lineages split or branch by speciation resulting in the generation of biodiversity
Ÿ All species have common ancestors
Ÿ Most evolutionary change results from natural selection
Simple definition
Ÿ Biodiversity: the variety of life on earth; the number and kinds of living organisms in a
given area.
Ÿ Adaptation: 1) (noun) any trait that contributes to fitness by making an organism
between able to survive or reproduce in a given environment 2) (verb) the evolutionary
process that leads to the origin and maintenance of such traits
Theory of evolution
Ÿ The central unifying concept of biology
Ÿ affects many other areas of knowledge
Ÿ One of the most influential concepts of Western thought
Theodosium Dobzhansky(1900-1975)
Ÿ Fruit fly geneticist & founder of the modern evolutionary synthesis
Major sub-fields in evolution:
Ÿ *Evolutionary mechanisms (microevolution)
Determine the ecological and genetic mechanisms responsible for evolutionary
change
Involve population-level studied of natural selection, adaptation and speciation
using diverse organisms
Testing of theoretical models by experiments in the laboratory and field
Interested in the process of change
Ÿ Evolutionary history (macro evolutions)
Determining evolutionary relationships of organisms in terms of common
ancestryàphylogenetics
Affinities of organisms provide a basis for classificationàtaxonomy & systematics
Comparative data from many sources : biogeography, morphology, development
and genomics
Current resources
Ÿ Water hyacinth-Eichhornia crassips
World record for clones, number of times it multiples itself
Make copy of themselves and live in different environment
Worlds worst weeds
Flowering fast when the roots touched soilàhave to multiply fast, otherwise the
canal drain out.
Search of the missing short-styled (s) morph of water hyacinth
Ø Founder effects
Ÿ Rats tail (how do they pollinate?)
Bird pollination evolved independently in many lineage of angiosperms.

Document Summary

Structure of dna (cid:159) mitosis & meiosis (cid:159) Small questions: answering small tractable questions can help contribute towards solving a big question. Large question: unlikely to be answered by one experiment; required multiple lines of evidence (ex. How questions: involve determine the physiological or genetic mechanisms responsible for aspects of a trait. Why question: involve determine the ecological function and adaptive significance of a trait. Approaches used in evolutionary biology (cid:159) observational: describe and quantify (cid:159) (cid:159) (cid:159) Experimental: manipulate a system to address a specific hypothesis; requires an experimental design and statistical analysis. Important assumptions about evolution verified by scientific study (cid:159) organisms on earth have changed through time (cid:159) (cid:159) (cid:159) (cid:159) most evolutionary change results from natural selection. Lineages split or branch by speciation resulting in the generation of biodiversity. Biodiversity: the variety of life on earth; the number and kinds of living organisms in a given area.