Biology 3593B Lecture Notes - Lecture 13: Microevolution, Convergent Evolution, Molecular Evolution

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11 May 2020

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What is it: the history of organismal lineages as they change through time, phylogenetic trees diagram representing closeness of relationship between species or populations. They reflect the evolutionary relationships among species or populations. Phylogenies: molecular genetics has enabled phylogenies be based on dna sequence to be developed. Reading an evolutionary tree: difficult especially if there is little info, some traits get transferred and carried on e. g. bobbed tail; uniform coat; stripes. Each traits has an origin point along the tree either at node terminal, node or root depending on how far back the trait goes (suggests how dominant it is): branch lengths = proportional to amount of genetic divergence. Between taxa it is possible to calculate time since divergence between taxa. Group of clade of this kind consists of ancestor and its descendants: polytomy: Node or branch point on phylogeny with more than two descendant lineages emerging.

Related Questions

1)Imagine we want to reconstruct the evolutionary relationships among a set of species, or among a set of populations of the same species. Would we use a single marker, or multiple markers, to construct our phylogeny? Explain why.

2)What is the difference between a gene sequence and a genome-wide SNP array? Describe how each might be used to address questions.

What problems does horizontal gene transfer cause for evolutionary biologists?

It can make reconstruction of phylogenetic trees difficult because it can obscure phylogenetic relationships.

It can cause physiological problems in some organisms, making it hard to study them.

It can make breeding between different individuals of the same species difficult.

Because it is transfer of genes between the same species, it can make individuals look more similar than they actually are.

All of the above

Which statement best describes the maximum parsimony approach to the reconstruction of phylogenetic trees?

A pathway is constructed that requires the minimum number of changes to arrive at the modern species from a common ancestor.

The tree is based on relationships that show the maximum probability of obtaining a set of characteristics.

Relationships on the tree are based on overall similarity between species.

Branches on the tree are constructed from the predicted date of speciation, measured in millions of years.

The best phylogeny is selected by comparing models representing random mutation and adaptive radiation.

ambermouse112

Which of the following have been used by scientists to determine evolutionary relationships and divergence times between primate species or lineages?

	A.	evidence from the fossil record
	B.	behavioral observations of living primates
	C.	molecular phylogenies
	D.	all of the above
	E.	A and C are correct

Problems with interpreting information from the fossil record include:

	A.	variation within one species may be misinterpreted (e.g. as multiple species rather than one)
	B.	differential preservation results in sample fossil populations which donât reflect the size of past populations
	C.	a species sometimes has to be defined on the basis of only one fossil specimen
	D.	all of the above
	E.	none of the above; scientists donât find any problems with interpreting fossils because the evidence is always so clear and unquestionable

Cultural practices - such as those pertaining to agriculture - can play a significant role in influencing the evolution of infectious disease microbes.

True
False

Populations that evolved to include high numbers of individuals with the "thrifty genotype" include higher frequencies of the following health problems:

	A.	influenza
	B.	obesity
	C.	diabetes
	D.	all of the above
	E.	B and C are correct

Human behavior is one of the critical factors that contribute to the evolution of more virulent (harmful) bacterial and viral strains.

True
False

Large agricultural and urban populations may be more vulnerable to infectious disease due to their:

	A.	larger population size
	B.	larger homes and dwelling structures
	C.	sedentary lifestyle
	D.	all of the above
	E.	both A and C are correct

Biology 3593B Lecture Notes - Lecture 13: Microevolution, Convergent Evolution, Molecular Evolution

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