Biology 1005 Final Homeostasis and Population growth

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Biology 1005 Final Homeostasis and Population growth
2012-11-13 14:44:22

From Homeostasis slides and population growth
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  1. a property of a living organism, that regulates its internal environment so as to maintain a stable, constant condition.
  2. Homeostasis has survival value because it...
    means an animal can adapt to a changing environment.
  3. The body will attempt to maintain the desired level of a factor to achieve ....
  4. What does an organism need to regulate?

    • •Ion levels (Na+, K+, O2)
    • •Nutrients: Sugar levels
    • •Water levels
  5. Animals use _____ adaptations to regulate body temperature
  6. On a cool morning a snake might ...
    move into a sunny area to absorb heat from the sun.
  7. What are some sources of heat gain or loss?
    Surfaces  →
    Air → 
    Sun → 
    • Conduction
    • Convection
    • Radiation
  8. What are the 2 categories of organisms based on how they regulate their temperature?
    Homeotherm, and Poikilotherm
  9. A Homeotherm basted organism...
    • Is Capable of maintaining its body temperature within a narrow range
    • Temperature is usually above that of its surroundings despite large variations in environmental temperature.
    • e.g. elephants, birds, girraphs
  10. A Poikilotherm based organism ...
    • Body temperature fluctuates with that of the environment.
    • Cannot maintain a constant body temperature, affected by environmental changes
    • e.g. fish and reptiles
  11. What aspects/structures of an organism may impact  the gain and loss of heat?
    • Size: bigger organisms change temperature more slowly
    • Shape: increase/decrease surface area for the conduction of heat
    • Legs: keeping the body off the surface (conduction)
    • Color: radiation of light/sun
    • Sweat: lose heat through evaporation
    • Location: move to minimize/ maximize conduction, convection or radiation
  12. _____is the main feature of all living organisms
  13. Population growth rate:
    rate at which the number of individuals in a population increase
  14. Two important models of population growth based on reproduction of organisms are

    Exponential Growth and Logistic Growth
  15. Things to remember about Exponential Growth
    • Population size expands by ever increasing increments during successive intervals (TIME goes on the bottom axis)
    • Growth is proportional to the current population size (N) the long axis
    • The larger the population gets, the more individuals there are to reproduce, the faster it grows
    • LAG at small size
    • J- shaped curve
  16. Exponential Growth Equation:
    ΔN/Δt = rN0
    • ΔN = change in population size
    • Δt = change in time
    • r = intrinsic rate of increase (difference between the birth rate and the death rate)
    • N0 = initial # of individuals
  17. I + B - E - D = populations size
    • •Immigration adds individuals
    • •Emigration subtracts individuals
    • •Births add individuals
    • •Deaths subtract individuals
  18. Population growth rate of most species is often limited/determined by various factors:
    Density, Distribution
  19. Density
    Number of individuals in some specified area of habitat.
  20. Distribution
    Spatial arrangement or pattern of a species over its habitat.

    • Proximity to other individuals also can have an overall effect.
    • Find mates
    • Predator Protection
    • Sharing resources….
  21. Any ____ ____ that is in short supply is a limiting factor
    essential resource
  22. Some Biotic factors in the environment are
    • Disease
    • Competition
    • Predation
    • Toxic effects of waste products
  23. Combination of limiting factors determines the ____ ____  of an area
    carrying capacity
  24. Logistic Growth Equation:
    • ΔN = change in population size
    • Δt = change in time
    • r = intrinsic rate of increase (difference between the birth rate and the death rate)
    • N0  = initial # of individuals
    • K = carrying capacity
  25. Logistic Growth occurs when...
    • Occurs when population size is limited by K (carrying capacity)
    • S-shaped curve
    • Bascally As size of the population increases, rate of reproduction decreases
    • Because of limiting resources
  26. Why is studying population growth important?
    • Microbiology: 
    • growth of bacteria (disease)
    • Conservation biology:
    • restoration of disturbed populations
    • prediction of yield
    • plant or insect quarantine
    • population growth of introduced species
    • Fisheries
    • prediction of fish dynamics
  27. Some interesting Facts:
    • Population now exceeds 7 billion
    • Rates of increase vary among countries
    • 200,000 people added each day
    • Fertility rate is highest in developing nations
    • Takes 4 years for world population growth to add the equivalent of another US