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General Biology: Organisms Coping with Temperature and Water

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  • What limits the range where organisms can live?
    Organisms have a range of conditions for survival and reproduction. Limits include environmental factors like temperature, water, nutrients, sunlight, species interactions, and geographic barriers.
  • What is environmental stress in biology?
    Environmental stress is a factor that decreases the rate of physiological processes, lowering survival, growth, or reproduction potential.
  • Define ecotypes.
    Populations with adaptations to unique environmental conditions are called ecotypes. They show genetic differences reflecting their native environments.
  • What is acclimatization?
    Acclimatization is a short-term, reversible physiological, morphological, or behavioral change in individuals to minimize stress from environmental challenges.
  • How does acclimatization differ from adaptation?
    Acclimatization occurs within an individual's lifetime and is reversible; adaptation is an evolved trait passed across generations improving physiological processes under stress.
  • What are two ways organisms cope with environmental stress?
    Organisms cope by tolerating stress (withstanding exposure) or by avoidance (preventing damage), such as migration or behavioral changes.
  • How do body appearance and season relate in some animals?
    Animals like the arctic fox change body mass and coat thickness seasonally to regulate insulation and temperature tolerance.
  • What is dormancy?
    Dormancy is a state of very low or no metabolic activity where growth and reproduction stop, allowing survival during extreme conditions.
  • Why does temperature matter for organisms?
    Temperature affects enzyme activity, membrane fluidity, and biochemical reactions; extreme heat denatures enzymes, cold slows reactions, and freezing stops many processes.
  • How do plants regulate temperature?
    Plants regulate temperature by opening/closing stomata and changing leaf morphology to control heat loss or retention.
  • Difference between ectotherms and endotherms in temperature regulation?
    Ectotherms rely on environmental heat to regulate body temperature; endotherms generate internal heat metabolically to maintain temperature.
  • What is countercurrent exchange in tuna?
    Countercurrent exchange warms arterial blood by heat transfer from venous blood in swimming muscles, helping tuna maintain body temperature.
  • How does body shape affect heat exchange?
    A larger surface area relative to volume increases heat exchange, making temperature regulation harder; smaller surface area reduces heat loss or gain.
  • Why is water essential for organisms?
    Water is a universal solvent for solutes, a medium for biochemical reactions, and makes up 60-90% of most organisms.
  • Explain osmosis in biological systems.
    Water moves from areas of low solute concentration (hypotonic) to high solute concentration (hypertonic) across a selectively permeable membrane.
  • How do marine fish maintain salt and water balance?
    Marine fish drink seawater, actively uptake water, excrete ions through gills, and produce concentrated urine to minimize water loss.
  • How do freshwater fish maintain salt and water balance?
    Freshwater fish do not drink water, produce dilute urine, actively uptake solutes through gills, and minimize water loss.
  • What adaptations help single-celled organisms conserve water?
    They require moist environments, adjust osmotic balance via membrane permeability, and may enter dormancy during dry conditions.
  • How do plants conserve water?
    Plants conserve water by opening stomata at night, developing waxy leaves, increasing root systems, and forming mycorrhizal relationships.
  • What are animal adaptations for water conservation?
    Animals have thick exoskeletons or skin, hair or feathers, and behavioral adaptations like nocturnality to reduce water loss.
  • How do kangaroo rats conserve water?
    Kangaroo rats convert fats to water, consume water-rich foods, are nocturnal, produce concentrated urine, and have specialized kidney loops to minimize water loss.
  • What are tradeoffs of conserving water in animals?
    Water conservation can reduce gas exchange, increase water needs (e.g., sweating), and limit feeding time due to behavioral avoidance.