Summary of module

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  • Taxonomy: 3 domains, Binomial classification- hierarchy, defining species, phylogenetic relationships.
  • Natural selection, speciation, evolution. How early humans evolved- role of bipedalism and anatomical adaptations.
  • Risk of sex- sexual vs. asexual 


  • Definition, exponential growth, logistic cuve, other patterns observed in nature. 
  • Exponential: formulae (rN), human popln growth, starlings-N. America, Paramecium. 
  • Density-dependent limitation factors: competition, space, food, water, waste, disease, predators.
  • Density-independent factors- hazards/extreme events e.g. Herons, UK- dip after some Winters
  • S-shaped curve to carrying capacity (k). N=K- popln growth =0.
  • Discontinous growth e.g. plants in temperate zones 
  • Examples- Flour beetles, Wildebeest, Willow tress-UK after introduction of Myxamatosis, 
  • MSY- over-exploitation of fish populations: passive vs modern drift nets, echo sounders, purse seine.
  • No pattern? Skylarks, UK.- but gradual decline
  • Boom-bust predator-prey cycle.
  • All patterns (logistical/cyclical/random)- have an "r" value in growth model- useful for land managers.


  • Habitat vs. ecological niche definitions
  • Resource prey gradient graph and environmental gradient graph
  • Principle of competitive exclusion
  • Inter-specific and intra-specifc. resource exploitation. 
  • Red and grey squirrels - maybe not competition?
  • Zonation of UK barnacles- Chthamalus vs. Semibalanus- definite competition-experiment.
  • Fundamental v.s realised niche- edited resource prey gradient graph
  • Example of niche differentiation- species of Tit in Paridae- subtle but effective
  • Niche dimension box graphs
  • Character displacement - galapagos finches, mud snails on tidal flats (ventrosa vs. ulvae).


  • Definition of predation. Define evolutionary fitness. Food chains + food webs
  • True predators, grazers, parasites, parasitoids.
  • How can we observe predation?- drag marks, prints, remains.
  • Monophagous(specialists); Oligophagous (restricted range); Polyphagous (generalist)
  • Specialist e.g. Lynx and snowshoe hare- unstable population cycles- 10 year oscillation cycles. Co-evolution- evolutionary arms race- selection pressures. Cost-benefit analysis. Searching/handling times vs. risk of starvation. 
  • Pied wagtails choosing fly size- 7mm= optimal size- most energy per unit effort/time. 
  • Prey switching- change searching image based on previous experience
  • Generalists- Guam snakes, brown bears, red foxes, guppies, water bug.

Disease and parasitism:

  • Definition of parasitism. Ectoparasites vs. Endoparasites. Effects= larger than predation.- Digenean flukes effect on mud snails compared to shorebirds. 
  • Vectors of disease. Energetic cost of disease on reproduction. e.g. Female western fence lizards, California- clutch sizes when infected with malaria. 
  • Energetic cost on chick mortality e.g. Mangrove finch chicks- anaemic due to parasitic larvae of Philornis downsi. Experiment- fumigated cotton balls- higher fledging success.; Cattle egret chicks- 24 ticks=fatal- blood loss and arbo-virus infection. - spraying nests with insecticide-lowered chick mortality,
  • Vectors e.g. Harp seals spread virus when range was further south due to climate change- crossed species barrier- other seals. Zoonotic disease.
  • Controlling disease- culling- fewer hosts- wipe out disease e.g. buffalo heardsin Yellowstone N.P. to stop spontaneous abortion due to bacterium brucellosis.
  • Presence of other species either: more vectors or buffer species- cant be infected. 
  • Rabies- Lysavirus =zoonotic- also in humans. Mortality =highly cyclic.
  • Co-evolution- if virus causes high mortality- fewer hosts- Myxamotosis- becoming less pathogenic over time. Although still hindering rabbit populations- grow when vaccine is administered. 

Other interactions (not predation or competition):

  • Symbiosis, commensalism, mutualism, neutral interactions
  • Loose to tight mutualisms. examples: Pseudomyrmex ant + acacia plant (S…


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