Transcript Slide 1

LIFE…AS WE KNOW IT!!
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• Biosphere : layer of Earth that supports life
roughly 13 miles thick ( 7 miles into atmosphere
and 7 miles down into the oceans !!!)
• Biomes : large regions of the globe defined by
similar climate (T and precipitation) and
vegetation
– specific place on the map
• Ecosystems: All of the living organisms and the
nonliving environment in a particular place
( lg. ecosystems – small ecosystems)
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http://www.blueplanetbiomes.org/world_biomes.htm
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POPULATIONS: group of organisms, in
same species (able to interbreed), in same
area, at same time…“the 3 S’s”
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Population Dynamics
• Populations change constantly in size and
composition…what types of things in the
environment limit the growth of a population?
***ANSWER!
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Population Dynamics
• Populations change constantly in size and
composition…what types of things in the
environment limit the growth of a population?
***ANSWER:
– Limited food and water
– Predator increase (including hunting)
– Climate and Weather conditions (drought, flood,
tornado)
– Diseases (immigration; close contact)
– Space
– Pollution
• They experience changes in their gene pool over
time:
– births, deaths, immigration (into), emigration (out of)
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2 FACTORS THAT LIMIT POPULATION GROWTH
• 1. Density-dependent factors = dependent on
the # of organisms in a given area.
*limited resources, predation, disease
*intraspecific (between members of the same species)
and interspecific (between members of different
species) competition
• 2. Density-independent factors =
environmental conditions that limit growth
(regardless of # of organisms).
*weather and climate are the most impt.
* “natural” disasters (flood, fire, tornado, hurricane,
etc.)
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Cover up!!!!!!
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Factors That Affect Population
Growth/Declin:
BIOTIC FACTORS:
ABIOTIC FACTORS
• predation
• disease &
• water
• shelter
• space
• weather
• climate
• sunlight
• nutrients (soil)
parasitism
• food availability
• mating
• human impacts
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Growth Curves
models that explain/depict how populations
change over time.
• 2 Types:
1. Exponential: “J” shaped curve
-rate of growth stays the same…continuous
-population size increases steadily
-ex. bacteria
2. Logistic: “S” shaped curve
-“J” shaped that is limited by a density-dependent
factor
-death rate = birth rate
-shows carrying capacity = the population size (max.
#) that an environment can support.
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examples
• Exponential growth
• Logistic growth
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Checking for understanding (3 parts)
• COMPLETE THE FOLLOWING (either on your iPad---then
email to me; OR on a half sheet of paper):
• Answer reading check question after
reading “Human Population” pg. 107
• Graphing: #7 on pg. 107
• Pg. 103 Fig. 1: What distinguishes one
zebra population from another zebra
population?
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