150.01 M2

• Temperature influences rates of chemical reactions, including those that control life’s essential processes
• All organisms are best adapted to a fairly narrow range of temperatures
• Organisms either tolerate or avoid environmental changes
• Factors affecting terrestrial microclimates:

  • Altitude
  • Aspect
  • Vegetation
  • Colour of the ground
  • Presence of bounders and burrows
• Factors affecting aquatic microclimates:

  • Physics of water
  • Specific heat of water
  • Latent heat of vaporisation
  • Latent heat of fusion
  • Riparian vegetation
• Principle of Allocation: expending energy on necessary life functions takes away energy from performing other functions
• Enzymes have physical optima

  • Taq polymerase has become an important tool in molecular biology
• Metabolism occurs at optimal temperatures
• Acclimation: physiological changes in response to temperature, reversible with changes in environmental conditions

  • Acclimatization: coordinated phenotypic response to multiple environmental stressors
• Psychrophilic

  • Thermophilic
• Thermal heat balance equation:

  Hs = total heat stored

  Hm = heat gained from metabolism

  Hcd = heat gained or lost from conduction

  Hcv = heat gained or lost from convection

  Hr = heat gained or lost through electromagnetic radiation

  He = heat lost through evaporation
• Boundary layer lowers convective heat loss
• Ectotherms regulate temperature through energy exchange with the environment

  • Endotherms rely primarily on internal heat generation
• RM endothermy: aerobic red muscles function as countercurrent heat exchangers
• Torpor: state of low metabolic rate and lowered body temperature

  • Hibernation in the winter
  • Estivation in the summer
• Water vapour density = amount of water in air

  • Saturation water vapour density = max quantity of water vapour air can contain
• Water potential = Ψo + Ψp + Ψm
• Water & Salt Movement:

  Ψseawater < Ψteleost < Ψfreshwater

  • Hyperosmotic
  • Hypoosmotic
• Matric forces decrease water potential because it allows adhesion or cohesion
• Water regulation equation:

  Wi = Wd + Wf + Wa - We - Ws
• Photosynthetically active radiation (PAR) - wavelengths which carry sufficient energy to drive light-dependent photosynthetic reactions

  • Quantified as photon flux density
• Plants grown at different light levels show varying light response curves and saturation points
• Stomatal control trades off water conservation vs energy gain, influenced by water availability
• Temperature can influence photosynthesis by influencing rates of photosynthetic activity
• Nutrient availability influences photosynthesis because enzymes like RuBisCO are N-rich
• Herbivores, carnivores, omnivores, detritivores obtain energy from organic compounds
• Holoparasites fully depend on its host for sustenance

  • Hemiparasites partially parasitise its host
• Develop myriads of adaptations for finding and obtaining food, consuming food, and absorbing its energy and nutrients
• Adaptive phenotypic convergence
• Mullerian mimicry - aposematic qualities are mimicked by hazardous organisms as well

  • Batesian mimicry - conspicuous qualities are mimicked by otherwise harmless organisms
• Type 1 feeding is characteristic of filter-feeding aquatic animals that feed on small prey

  • Type 2 feeding rates are limited by the time spent searching or handling food
  • Type 3 feeding rates increase more slowly at low prey density
• Marginal value theorem applies profitability in foraging patches

  • Tangent maximises profitability and determines optimal giving up time
• Prey exhibit behaviours that can prevent detection or deter predators
• • Energy input vs output determines an object’s heat energy change and internal temperature
• Reproductive Behaviour:

  • Sexual selection results from differences in reproductive rates among individuals due to differences in their mating process
  • Intrasexual competition: individuals compete for mates
  • Intersexual selection: one sex consistently chooses a mate based on a particular trait
• Parental Investment:

  • Parental investment increases offspring survival and reproductive success but may limit investment in other offspring
  • Anisogamy: Maternal investment includes nursing, while paternal investment includes a brood-pouch "pregnancy"
• Reproductive Mating System:

  • Refers to the number of mating partners and the pattern of parental care
  • Aims to maximize reproductive success or fitness
  • Types include monogamy, polygyny, polyandry, and promiscuity
• Social Behaviour:

  • Sociality involves cooperation between individuals or various forms of assistance, such as defense against predators
  • Eusociality includes individuals of more than one generation living together, cooperative care of young, and division of individuals into castes
• Cooperative Breeders:

  • Inclusive fitness is determined by its own survival and reproduction, plus the survival and reproduction of individuals with whom the individual shares genes
  • Kin selection favors helping behavior towards genetic relatives
• Caveats of Group Living:

  • Greater energy expenditures
  • More competition for food
  • Higher risks of disease