Vocabulary: Ecology - Michigan State University Ecology • Ecosystem ... – ALL organisms have...
Transcript of Vocabulary: Ecology - Michigan State University Ecology • Ecosystem ... – ALL organisms have...
Vocabulary: Ecology • Ecosystem • Community • Population • Abiotic/Biotic Factors • Producers • Consumers • Decomposers • Trophic (levels,
structure) • Biodiversity
• Biomass • Primary Production • Net Primary Production • Photosynthesis • Cellular Respiration
Carbon cycle • Pools (reservoirs) • Fluxes • Sinks vs. sources • Food chains • Food webs
1. Interpret phylogenetic trees. 2. Use phylogeny to explain that evolution is NOT a
linear progression from primitive to advanced species.
3. Describe interspecific interactions that define and organize community structures
4. Predict the nature and direction of selective pressures acting on those interactions
Objectives, 11/06/08:
• Clades = nested groups – branches can “rotate”
• order is changed, but relationship is maintained
• Nodes - points in time when populations became reproductively isolated
• Based on body plan (morphology)
• Based on molecular information (RNA and/or DNA)
Similarities? Differences?
Woese, 1977 • generate “tree of life”
• chemical basis for relatedness (SSU RNA from ribosomes)
• Observations: – ALL organisms have
ribosomes (inference?)
– rRNA sequences change over time due to random mutation. (more time more opportunity for mutation)
Woese Hypothesis: • If organisms are descended from common
ancestor, then rRNA sequences will be more similar in closely related organisms, less similar in more distantly related organisms.
Woese’s Conclusions: • 3 major groups (= Domains):
– Bacteria – Archaea – Eukarya
• Prokaryotes are DIVERSE! (think: Kingdom-level differences btw plants,
animals, fungi)
• Whittaker’s “Kingdoms” do not reflect phylogeny of organisms – Monera obsolete
Interspecific Interactions:
Species 1 Species 2
Mutualism
Predation, Parasitism
Competition
Commensalism
Effect is +/-/0 depending on its impact on fitness for the species
Competition
• Species overlap in resource requirements and resource is limiting
• Selection will favor traits that reduce competition