Download Population Dynamics

Population
Ecology
TERMS
• Biotic: all living organisms.
• Ex. Trees, flowers, moss, birds, monkeys,
people, mold, fish, plankton, pumpkins,
grass, giant squid
• Abiotic: all non-living factors
• Ex. Wind, temperature, rocks, water,
altitude, sunlight
TERMS
• Habitat: home or environment of a living
organism
• Ex. The habitat of the chimpanzee is the
rainforest
• The habitat of the saguaro cactus is?
TERMS
• Niche: the role and position a species has in
its environment
• how it meets its needs for food and shelter
• A species' niche includes all of its
interactions with the biotic and abiotic
factors of its environment
Red Squirrel’s Niche
The red squirrel lives in coniferous forests. It makes its
nests in a variety of places including hollows in the
ground, in tree hollows, logs or crotches in trees. The
red squirrel is very vocal and chatters, growls and
screeches. It eats insects, seeds, bark, nuts, fruits,
mushrooms and pine seeds or cones. It also stores
nuts and seeds in piles under logs, at the base of trees
and underground. It doesn't always find or eat all of
the seeds and nuts it has stored. Because of this, the
red squirrel fills an important niche in spreading seeds
in the forest. Its predators are hawks, owls, and foxes.
Population Dynamics
• Population:
• All the individuals of a species that live
together in an area
• Community:
• All the populations of different species
that live together in an area
Population Dynamics
• Ecosystem:
• The community plus all the abiotic factors
in an area
• Biosphere:
• The entire planet, with all biotic and abiotic
factors involved
What is this picture?
Population
What is this picture?
Biosphere
What is this picture?
Community
What is this picture?
Ecosystem
What is this picture?
Population
What is this picture?
Community
Key Features of Populations
Density: measurement of population per unit
area or unit volume
Pop. Density = # of individuals ÷ unit of space
How Do You Affect Density?
1.
Immigration: movement of individuals into a population
2.
Emigration: movement of individuals out of a population
3.
Density-dependent factors: Biotic factors in the
environment that have an increasing effect as population
size increases (disease, competition, parasites)
4.
Density-independent factors: Abiotic factors in the
environment that affect populations regardless of their
density (temperature, weather)
Factors That Affect Future Population Growth
Immigration
Natality
+
+
Population
Emigration
-
Mortality
How Are Populations Measured?
• Population density = number of individuals
in a given area or volume
• Count all the individuals in a population
Carrying Capacity
• Carrying Capacity:
• The maximum population size that can be
supported by the available resources
• There can only be as many organisms as the
environmental resources can support
Graphing Carrying Capacity
Factors Limiting Growth Rate
• Declining birth rate or increasing death rate
are caused by several factors including:
• Limited food supply
• The buildup of toxic wastes
• Increased disease
• Predation
“Booms” and “Busts”
Reproductive Strategies
• R Strategists
 Short life span
 Small body size
 Reproduce quickly
 Have many young
 Little parental care
 Ex: cockroaches,
weeds, bacteria
Reproductive Strategies
• K Strategists
 Long life span
 Large body size
 Reproduce slowly
 Have few young
 Provides parental
care
 Ex: humans,
elephants