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Lecture 30: Dispersal & Locomotion (Advantages of dispersal (Escape…
Lecture 30: Dispersal & Locomotion
Dispersal: movement of an organism away from a parent or away from an existing population
Locomotion: the ability to move around a habitat and among habitats (necessary for food, escape, mating, microhabitats)
Advantages of dispersal
Escape from local crowding/competition
Avoid closely related individuals (inbreeding)
Colonization of new or more suitable habitats
Avoid predators or pathogens that occur on the parent (particularly when parent is large or long-lived)
Janzen-Connell hypothesis- in trees, seed distance from parent increases chances of survival
Life cycle stages with dispersal:
Gametes (or larval forms)
Mature organisms capable of locomotion
Spores, pollen or seeds in plants
Spores in fungi
Locomotion is important for:
Mating
Predator Avoidance
Gathering Food
Thermoregulation
Three types of skeletal muscles
Cardiac- Cardiac muscle cells are smaller, highly branched, and uninucleate- gap junctions
Smooth Muscle- found in the gut walls, circulatory system and other internal organs and is arranged in sheets. Contractions are slower & more sustained
Skeletal
Bundles of muscle in parallel
Actin and myosin make up microfibrils; multiple myofibrils make up a single muscle fiber
Release of Ca+ from the sarcoplasmic reticulum triggers muscle contraction
Two types of muscles
Slow Twitch (red Muscle)
Many mitochondria, glycogen & fat reserrves
Fast twitch (White muscle)
High ATPase activity, recycle cross-bridges rapidly
Three energy sources for Muscle performance: Immediate (ATP and creatine phosphate), glycolytic (in cytoplasm, leads to lactic acid), oxidative (in mitochondria)