Download Population Biology

 Ecological
organization:
• Species
• Population
• Community
• Ecosystem
• Biome
• Biosphere
Species

Group of similar organisms that can
breed and produce fertile offspring
Population

group of organisms, all of the same species,
which interbreed and live in the same area.
Community

groups of different populations that live
together
Ecosystem

Collection of organisms that live in a place
with the nonliving environment
Biome

Group of ecosystems with the same
climate and vegetation
Tropical rain forest
Temperate grassland
Temperate forest
Tundra
Tropical dry forest
Desert
Mountains and
ice caps
Tropical savanna
Temperate woodland
and shrubland
Northwestern
coniferous forest
Boreal forest
(Taiga)
Biosphere

The part of the earth where life exists
including land, water, air, and
atmosphere
 We’re
going to Study the population level
 What is a Population?
Population
Density - Number of
individuals per unit area or
volume.
Population Distribution - Pattern
of dispersal of individuals within
the area of interest.
Population Density or Population
Distribution?
Random
Uniform
Clumped
Birth potential: max # of offspring per birth
1.
•
eg. Dog-5 human-1 Fruit fly – many
Capacity for survival: the # of offspring that reach a
reproductive age
2.
•
eg. Humans - 15 Cats – 1
Procreation: the # of times that species reproduces
per year
3.
•
eg. Human - 1
fruit fly- every few days!
Length of reproductive life: the # of years that an
organism can reproduce
4.
•
•
•
•
eg. Salmon- only once
Elephant- 22 month gestational period
Humans- 9 months
Whale- 11 months
2. Limiting Factors:
• Environmental factors that prevent an
organism from reaching its biotic
potential.
• 2 types
 Density dependent
 Density independent
 There
are 2 main categories of limiting factors:
• 1. Density-dependent factors- factor that depend on
the size of the population to act
• Density-independent factors- affect all populations
equally, regardless of population size
 Density-dependent
limiting factors include:
 competition
 predation
 parasitism
 Disease
 These
factors exist when a population is large
and dense.
 They do not affect small, scattered populations
as greatly.
Parasitism
 Organisms that live and feed on other organisms
 The host is the organism that the parasites live on.
 parasites don’t kill the host but may weaken
causing death
Predator/Prey
 One organism kills and eats another organism.
 Prey is being eaten - predator does the eating.
Competition
 Two or more organism
of the same or different
species use the same
limited resources.
 Density
Independent Include natural
phenomena, such as weather events
 unusual weather
 natural disasters
 seasonal cycles
 certain human activities—such as damming rivers and
clear-cutting forests
 Carrying
Capacity:
 The largest population of a species that
can be sustained in an ecosystem over
time
 Population
Graphing Worksheet
Exponential Growth in a population
J-curve
Occurs when a population starts out small and
no limitations on resources.
 Eventually
the
bacteria will grow
until a factor limits
growth
 Amazingly these are
called limiting
factors!!
Occurs when there are limiting factors on a
population and the carrying capacity is
reached
Bacteria Growth
Key
phases
Slow Growth
Rapid growth
Steady State
Decline or death
phase