APES- chapter 6 (animal populations)

Individual

refers to just one organism

population size

is the total number of individuals within a defined area at a given time

direct count (census)

Count um up! The group is individually counted.

sampling (quadrat method)

Identify an area and multiply by total amount to find the entire area

ex) if a biologist counts 10 squirrels living in a 200 square foot area, she could
predict that there are 100 squirrels living in a 2000 square foot area.

Capture-recapture

In this procedure, biologists use traps to capture the animals alive and mark them in some way. The animals are returned unharmed to their environment. Over a long time period, the animals from the population continue to be trapped and data is taken on how many are captured with tags. A mathematical formula is then used to estimate population size.

ex) California Condor

Population density

Number of individuals per unit area

ex) high density of people in the city low density of people in the country side

Population

all individuals of a single species living in a given area at a given time

Community

all of the various life forms in an ecosystem

Good things about a high population density

• grouped for protection

• finding mates

• genetic diversity

Bad things about a high population density

• spread disease

• greater competition

• vulnerable to attack (easier to find)

Good things about a low population density

• more space

• more recorces

Bad things about a low population density

• no help from the group

• little genetic diversity

• hard to find a mate

Population distribution

description of how individuals are distributed to different locations

random population distribution

• no particular pattern

• typical for many (not all)

uniform population distribution

-organisms spread out very evenly
-Typical of territorial birds
-Helps avoid competition

ecosystem

are specific areas that
include abiotic and biotic components

Biosphere

 all life on Earth

Clumped population distribution

-grouped near resources
-Good for feeding or protection

Limiting resources

something a population CANT live without, not unlimited (can be dependent or independent)

Density-dependent factor

limits on population growth that are directly related to the size of the population

Carrying Capacity (K)

the limit of how many individuals in a population the environment can sustain

Density-independent factors

limits on population growth that are not related to the population size (usually physical or chemical)

ex) tornado over 10 trees or 100 trees…still going to loose a tree

Exponential growth

• population grows at a fixed rate

• nor limited by recorces, growth is very rapid

• density independent growth patern

• shown by a J curve

  ex) St. Matthew Island, Alaska

Logistic Growth

exponental growth that slows when it reaches the carrying capacity

• turns into an S shaped curve

Overshoot

exponental growth then crashes

Oscillating

There is a pattern of overshoot from the carrying capacity then dieing off

K-selected species

“quality over quantity”

• low growth rate

• population size determined by carrying capacity

• density-dependent population regulation

• slow population growth

Ex) humans

r- selected species

“quantity over quality”

• high growth rate

• population size determined by large overshoots and rapid die-offs

• density independent population regulation

• fast population growth

Ex) frogs

Type I population survivorship growth curves

these live long then die off in large numbers at old age (K-selected species)

Type II population growth curves

relatively constant decline in survivorship over time

Type III population growth curves

many births, but few survive a long time ( r-selected species)

Provisioning Services

The products directly obtained from ecosystems ex) food

Supporting Services

Indirect services that are necessary for the production of all other ecosystem services. ex)the water cycle

Regulating Services

the benefits obtained from the regulation of ecosystem processes ex)pollination

Cultural Services

non-material benefits that people obtain from ecosystems ex)making recreational parks look nice

competition

individuals competing for a resource

interspecific competition

between different species- both expend energy/cause harm

competitive exclusion principle

adapt or die

Intraspecific Competition

between same species

Resource Partitioning

Two species overlap and must  divide a resource based on morphology or behavior

Temporal Partitioning

Collect resources at different times

ex) a nocturnal animal like an owl

Spatial Partitioning

Different areas
ex) Birds eat same insects from top vs. bottom of tree

Morphological Partitioning

Adaptive radiation (adapting quickly)

ex) darwin’s fintches

symbiotic relationships

animals interactions with each other, some examples are:

• mutralisim

• commensalisim

• parasitisim

Keystone species

have a PROFOUND affect in the comunity

ecosystem enginer

creates/ maintains a habitat for other species

ex) a beaver

Population sex ratio

how many males to females

population age structure

how many individuals fit into certain age categories

What is a population growth rate?

the number of offspring an individual can produce minus the deaths of the individual/ its offspring during the same time period.

succession

the predictable replacement of one group of species by another group of species over time

primary succession

bare rock. no soil. soil never existed.

secondary sucession

disturbed area, but has not lost its soil. This is much quicker than primary succession.

what is the term for populations moving into an area?

immigration

what is the term for populations leaving an area?

emigration