Evolution3 - Evolution #4, 5: Cladistics, Molecular...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Investigating the tree of life phylogeny = (Grk phylon, tribe + genesis, origin) = evolutionary history of a species or group of species; making use of the fossil record & systematics systematics = analytical approach to understanding the diversity & relationships of molecular systematics = uses comparisons of DNA, RNA, & other molecules to o Phylogenies are based on common ancestries inferred from fossil, morphological, & molecular evidence fossil record o sedimentary rocks are the richest source of fossils, but other mediums are used as well o fossil record is based on sequence in which fossils have accumulated in such strata o fossils inform phylogeny only if their age can be determined o fossil record is a substantial, but incomplete chronicle of evolutionary change o fossil record is biased in favor of abundant, long-lived, widespread species w/ hard shells, skeletons, or other parts that facilitated their fossilization o in general, organisms that share v similar morphologies or similar DNA sequences are likely to be more closely related than organisms w/ vastly diff structures or sequences o in some cases, the morphological divergence betwn related species can be o sorting homology from analogy analogy = similarity due to convergent evolution rather than shared ancestry ( homology ) convergent evolution occurs when similar env’tal pressures & natural selection produce similar/analogous adaptations in organisms from diff evolutionary lineages ex) moles: Australian marsupials vs N American eutherians distinguishing betwn homology & analogy is critical in reconstructing phylogenies ex) bat forelimb is homologous to those of other mammals, but analogous in function to a bird’s wing homoplasies = (Grk to mold in the same way) = analogous structures that have evolved independently the more points of resemblance that 2 complex structures have, the less likely it is that they evolved independently o evaluating molecular homologies molecular comparisons of nuclei acids often pose technical challenges
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
computer programs & mathematical tools have to account for & distinguish betwn “distant” homologies and coincidental matches in extremely divergent sequences Phylogenetic systematics connects classification w/ evolutionary history Carolus Linnaeus & taxonomic classification of plants & animals based not on evolutionary relationships, but simply on resemblances binomial nomenclature: genus + specific epithet Latinized
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/24/2009 for the course BIO 1B taught by Professor Carlson,mischel,power during the Fall '07 term at University of California, Berkeley.

Page1 / 8

Evolution3 - Evolution #4, 5: Cladistics, Molecular...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online