Populations

Population Biology

Biology 1 Honors

​Learning Target

qDescribe how limiting factors can change a population’s carrying capacity. 

qIdentify the carrying capacity of a population on a graph and in a text.

qDescribe and calculate population size using the number of births, deaths, immigrants, emigrants in a population.

Community=​ interacting group of various species in a shared/ common location

Population = more than one of the same species in a specific area


Species=a group of organisms that can reproduce with one another in nature and produce fertile offspring

​What is a population?

• Death (Mortality)

• Emigration-movement of individuals out of a population

Decrease

• Birth (Natality)

• Immigration-movement of individuals into a population

Increase

Factors Affecting Population Size

​Population change = (births + immigration) – (deaths + emigration)

Multiple Choice

If a pack of wolves experiences 5 births and 2 deaths over the course of a year, 1 wolf immigrates into the pack and 3 emigrate, what is the population change the pack experiences?

• Increase

• Decrease

• Stays the same

Multiple Choice

If a population of rabbits experiences 20 births and 30 deaths over the course of a year. 12 rabbits immigrates into the population and 5 emigrate, what is the population change over that year?

• Increase

• Decrease

• Stays the same

Multiple Choice

Which graph do you think represents a population growing under ideal (best) circumstances?

• Graph A

• Graph B

Exponential Growth

Happens when a population moves into an area previously uninhabited area-TONS of resources allows for populations to grow without limits

Logistic Growth

Happens when a population has limited resources in their habitat.
The population size is limited based on available resources.

Draw

Draw a population curve for a population of rabbits that reproduce rapidly.  After 5 generations the rabbits start to reach the capacity of space in which they live.  They are running out of habitat space. 

Is there a limit to how big populations can get?

The carrying capacity is the maximum number of individuals of a particular species that an environment can support long term. All environments have carrying capacities which can change due to changes in available resources.

What determines carrying capacity size?

A limiting factor is any factor that controls the growth of a population.

Open Ended

What is the carrying capacity of the population shown in the graph. Your answer should be a number.

Biotic vs Abiotic

Biotic Factors- Things in an ecosystem that were living or once living


Abiotic Factors- Things in an ecosystem that were never living

Categorize

Options (8)

Wind

Fire

Water

Sunlight

Animals

Protists

Fungi

Plants

Organize these options into the right categories

Abiotic Factor

Biotic Factor

Limiting Factors-Density Dependent

Any factor in the environment that depends on size of the population.


Usually include BIOTIC factors like: Disease, predators, competition for resources (food, water, sunlight, etc)

Limiting Factors-Density Independent

Any factor in the environment that occurs, independent from population size


Usually include ABIOTIC factors like:
Fires, floods, natural disasters, human impact

Categorize

Options (15)

Competition

Predidation

Disease

Flash flood

Hurricane

Fire

Parasitism

Resource limitation

Food availability

Tornado

Earthquake

Tsunami

Drought

Volcanic eruption

Rising sea level

Organize these limiting factors into the correct categories

Density Dependent

Density Independent

Multiple Choice

Which of the following is most clearly a case of density-dependent population regulation?

• the summer drying of savanna grass for an insect that feeds on grass sap

• 
  the first hard frost of fall for a population of annual morning glory vines

• a dangerous new flu strain that is transmitted among humans by sneezing

• the occurrence of rainstorms for an opportunistic desert annual