Practise using taxonomy, cladograms, molecular evidence and molecular clocks to infer evolutionary relationships and classification.
46 questions in this syllabus scope, with question parts counted together.
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Evolution causes gene pools to change over time and new species to be formed.
Explain how a newly discovered plant species would be classified and named.
The scientific name of the great egret has recently been changed from Casmerodius albus to Ardea alba.
What is a possible reason for the reclassification of egrets?
Allopatric speciation
Discovery of different ancestry
A change in the mating behaviours
Change in habitat and geographic range
There are many closely related Canis species in North America including the grey wolf (C. lupus), eastern wolf (C. lycaon) and western coyote (C. latrans). Hybridization can occur between members of these species.
For example, during the last 100 years, hybridization has occurred between western coyotes (C. latrans) and eastern wolves (C. lycaon) in the area of Ontario shown by a star in the map shown below.
Genetic evidence for hybridization is based on identification of haplotypes (combinations of linked alleles in clusters of similar genes) that exist in mitochondrial DNA (mtDNA) of Canis populations. The populations in this study were the Minnesota-northwestern wolf, southern Ontario coyote and northeastern coyote. Assume that all animals in each Canis population have the same mtDNA haplotypes.
Discuss briefly whether there is genetic evidence to show a common ancestor for the Minnesota-northwestern wolf, the southern Ontario coyote and the northeastern coyote.
Which encircled area shows a clade?
The evolutionary clock estimates the time elapsed since species separated from a common ancestor based on fossil evidence. The graph shows the number of differences in the DNA sequences (nucleotide substitutions) coding for certain polypeptides in 11 closely related mammals.
State the relationship between divergence time and number of substitutions.
Discuss the use of amino acid sequences of proteins as the basis for constructing cladograms.
Identify a type of information, other than amino acid sequence, that could be used to construct a cladogram.
Outline the use of parsimony analysis when choosing between different possible cladograms.
What can be deduced from the cladogram?
Tortoises do not have lungs.
A tortoise and a tarsier are more closely related than a tiger and a tarsier.
A tuna is equally closely related to a toad and to a tiger.
Tigers have fur and 5-digit hands.
Some plant families, such as the figwort family, have been reclassified on the basis of evidence from cladistics. Explain the methods that have been used recently to reclassify groups of plants.
Domain is a taxonomic level above kingdom that has been used to classify living organisms into three groups.
What has provided the evidence for classification of organisms into domains?
Ribosomal RNA (rRNA) base sequences
Mitochondrial DNA base sequences
Cell wall structure
Amino acid sequence of ATP synthase
