Ecology Intro - Lake Stevens High School

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Transcript Ecology Intro - Lake Stevens High School

 Good Morning AP Bio!!
 We will go over the Safety Contract first today…please have it out 
 We will also finish our notes from yesterday.
 Pillbug lab prep is tomorrow…bring bugs by Thursday.
 You will need your comp lab notebook for tomorrow.
 You will get reading questions for Chapter 51 today. These will be
due TUESDAY along with your summer homework. (No reading
questions for Ch. 53-54)
 This is the day we will be taking our first Quiz! YAY!!
AP Biology
Chapters 53.1-3, 53.5
 Population: group of individuals of a single species living in the
same general area who interact and interbreed
 density: number of individuals per unit area
not a static number...constantly changing (births, deaths,
immigration, emigration)
 dispersion: pattern of spacing among individuals, indicates
social interactions in a population
clumped, uniform, or random
territoriality also influences dispersion
 Not easy to count all individuals in a population...use mark-
recapture method to estimate population sizes
 Survivorship Curves
 graphical representation of number of organisms alive in a population over
time in age ranges (death rate)
 Type I: low death rates early in life, increases in older age-groups
humans, elephants, primates and other organisms with lots of parental
 Type II: constant death rate over life span
squirrels, rodents, plants
 Type III: high death rate in younger ages, death rate declines (levels off) in
older age groups
organisms with large numbers of offspring and little parental care
(invertebrates and fishes)
 Exponential Growth
 rapid growth, occurs in
times of unlimited resources
(no carrying capacity)
 produces a J-shaped curve
population growth= rmax (N)
rmax = maximum per capita
growth rate of a population
N= population size
 Logistic Growth
 growth limited by a
carrying capacity
(number of individuals
an ecosystem can
 varies with changing
 growth rate approaches
zero as the carrying
capacity is reached
r= r max = maximum per capita growth
N= population size
K= carrying capacity
 Factors regulating population size
 density-independent: does not influence the birth or death rate
 natural disasters, weather, sunlight, temperature
 density-dependent: increases death rate, decreases birth rate
 competition, predation, intrinsic physiologic factors, waste
buildup, territoriality, disease
 negative feedback!
 Species Interactions
 two or more species interacting in a positive, negative, or neutral
 competitive exclusion: two species competing for the same
resource cannot coexist permanently; one species will use the
resource more effectively and outcompete the other species
 symbiosis: individuals of two or more species live in direct close
contact with one another
 cooperative behavior: organisms work together for mutual benefits
(social animals, insects)
individuals of a different species
-/- compete for a resource that limits
their growth and survival
Bison and grasshoppers both
compete to eat grass
one species (predator) kills and
eats the other (prey)
an organism eats all or part of a cows and sheep eat grass; manatee
eating sea grass
an organism (parasite) eats and tapeworms in small intestine; fleas
lives on or inside another (host)
on outside of dog
Commensalism +/0
lion attacking and eating an
benefits both species
nitrogen fixing bacteria and
legumes, bacteria in digestive
one species benefits, the other is
neither hurt/benefited
birds and grazing animals,
barnacles and whales