BIO1042 Lecture Notes - Lecture 1: Species Richness, Molecular Clock, Carbon-14
6 Aug 2018
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Species diversity is determined by species richness and evenness. Diversity between species (species diversity or richness) 50% of plant species found on earth are found in tropical rainforest. Available energy: heat + water = available energy, more energy, more individuals can survive, more species can coexist, higher species richness, low energy. Hypothesis 2: the rate of diversification was high in tropical rainforests, diversification rate = (speciation rate) (extinction rate) Similarities in traits due to shared ancestry homology. Some traits are similar due to convergent evolution analogy. Ribosomal dna: evolves slowly, good for studying divergence that happened long time ago. Mitochondrial dna: evolves fast, good for testing more recent divergence. Using shared homologous traits to construct phylogenetic trees. Step 1: choose group you want to study. Step 2: choose homologous traits that are derived. Molecular clock: estimation of absolute time of divergence. Assumption: dna substitution rate is constant over time. Number of nucleotide substitutions time since divergence.
