BIO1101 exam 1 - Chapter 26 Explain importance of...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 26 Explain importance of distinguishing between homology and analogy Analogy: similarity due to convergent evolution acquisition of same traits by unrelated individuals ex. We have legs and crickets have legs. Maple seed wings and bird wings Homology: similarities due to share ancestor traits ex. Lineage. Bat wings and primate arms; 1,800 plus gene loci in mice and humans. Bat and bird wings are homologous as forelimbs, but analogous as functional wings Homology can be distinguished from analogy by comparing fossil evidence and degree of complexity. More complex two similar structures are, more likely they are homologous. Distinguish between following terms: Monophyletic – a taxon is monophyletic if a single ancestor gave rise to all species in that taxon and to no species in any other taxon. Paraphyletic – a taxon is paraphyletic if it excludes species that share a common ancestor that gave rise to the species included in the taxon. Polyphyletic groups – a taxon is polyphyletic if its members are derived from two or more ancestral forms not common to all members.
Background image of page 1

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

View Full DocumentRight Arrow Icon
In comparison with its ancestor, an organism has both shared and different characteristics Shared ancestral character - character that resulted in the taxon of the anscestor Shared derived character - novolity that all ansestors didn’t have ex mamilaian hair. Anscestors don’t have it Orthologous genes - homologous gene sequences that arise when a species diverges into two separate species Paralogous genes: homologous gene sequences arise when a gene in an organism is duplicated to occupy two different positions in same genome. Clade: group of species that includes an ancestral species and all its Maximum parsimony: assumes tree that requires fewest evolutionary events Synapomorphy: a trait shared by two or more taxa and their most recent common ancestor, whose ancestor in turn does not possess the trait of descendants. Discuss molecular clock and discuss their limitations. Molecular clock uses constant evolution rates in some genes to estimate absolute time of evolutionary change, assumes that maturity rates for genes (proteins) of interest are relativity constant. Differences in generation time and metabolic rates are two factors that may affect maturation rates and make the clock less reliable. Neutral theory: much evolutionary change in genes and proteins has no effect on fitness and therefore not influenced by darwinian selection. Rate of molecular change in these genes and proteins should be regular like a clock Define horizontal gene transfer and explain how it complicates phylogenetic trees Horizontal (lateral) gene transfer: gene movement from one genome to another; can involve plasmids, mitochondria, chloroplasts, etc.
Background image of page 2
Horizontal gene transfer complicates efforts to build a tree of life. Horizontal gene transfer is defined to be the movement of genetic material between bacteria other than by descent in which information travels through the generations as the cell
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 21

BIO1101 exam 1 - Chapter 26 Explain importance of...

This preview shows document pages 1 - 4. Sign up to view the full document.

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