Pretest Unit 3: Population Ecology1. What is a population and how do

ecologists study it2. Explain the difference between a niche

and habitat3. Explain the predator/prey relationship

and carrying capacity on the graph. 4. Explain why animals fight5. Explain how certain factors limit a

population6. Explain animal extinction and how it

affects an area 7. What is succession and how does it

occur?

Population Ecology

Species, Populations, Community,

and sampling

• LT: Organisms occupy a specific area

Species and Community

• Fact 18 A species is a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce.• Fact 15 A community is all the different populations

that live together in an area.

populations• Fact 16 A population is all the members of one

species in a particular area. • the entire group of items or individuals being studied

• Populations change over time• There are many factors that influence a population

• Natural • Unnatural

• Fact 38 Population density (number in an area) has a great impact on ecosystems• Population dynamics is the study of how the

characteristics of the population change in response to changes in the environmental conditions

Bellwork` 10/30

1. What are three things we learned about yesterday?• You must have a sentence about each one

Sampling• Sample: a part of the population being studied• Sampling populations gives an idea of • Size- how many• Density- how many in a specific area• Dispersion- how close or far away from each other• Location- where species are located

• A representative sample of the population is needed in order to make a valid inference, or an accurate prediction based on data• Survey: a method of gathering information about a

specific group of items or individuals

• What is the population?–All students in the school

• What is the sample?– Students in the seventh grade homeroom that

was surveyed

• Biased or unbiased?–Biased. One class of 7th graders does not

accurately represent all students in the school.

Example 1: A 7th grade homeroom was surveyed to determine how many texts students at Olean Intermediate Middle School send each day.

Example 2: To track migration patterns of a particular species of bird, scientists randomly tag, release, and track 50 birds of that species.• What is the population?

• The species of bird being studied

• What is the sample?• The 50 birds that the scientists tagged• Tagged birds are specially marked birds that are

tracked. Scientists use the data on these birds to make generalizations about an entire bird species.

• Biased or unbiased?• Unbiased. The birds tagged were randomly

selected.

Four factors of population change

• Natality - births within the population • Mortality - deaths within the

population• Immigration =-arrival of

individuals from outside the population • Emigration =-departure of

individuals from the population• Growth rate formula - • (Crude birth rate + immigration rate)

- (Crude death rate + emigration rate) - Growth rate

Population changes affect communities

• As population in one species declines, other species may appear• Human development now displaces other

species and threatens biodiversity

Picture Mapping

• Today you will create a visual representation about the topics we discussed• Only pictures• No words• Detailed enough for a random person to understand the

topics

•Species, Population, Community, Sampling.

Habitat and

Niche NotesLT: Organisms occupy a specific area

• Habitat - A habitat is the specific environment that provides the things an organism needs to live, grow and reproduce.• Includes living and nonliving elements• Scale-dependent: from square meters to

miles• each organism thrives in certain habitats,

but not in others (habitat use)

• Habitat selection - the process by which organisms actively select habitats in which to live• Availability and quality of habitat are crucial

to an organism’s well-being

• Niche A niche is the role an organism plays in its habitat, or how it makes a living. • total way of life or role of a species in an

ecosystem• Habitat use, food selection, role in

energy and nutrient flow• Interactions with other individuals

• Specialists - species with narrow niches and very specific requirements• Extremely good at what they do, but

vulnerable to change

• Generalists = species with broad niches that can use a wide array of habitats and resources• Able to live in many different places

Predator and Prey Interactions

Organisms interact in different ways

• Predator prey interactions• A predator is the organism that does the killing in a predation

interaction. • Prey is an organism that is killed and eaten by another

organism.

• Competition• Competition is the struggle between organisms to survive as

they attempt to use the same limited resource.

• Cooperation• Cooperation is the process of groups of organisms working or

acting together for their common/mutual benefit

Population SizeA concept map of what effects the size of a population.

POPULATION SIZE

Food

plenty of food

population grows

food shortage

population fallsDiseaseovercrowding

increased aggression / competition for resources

increase in predators

Decrease in predators

Predators

Animals that eat other animals

animals that eat other animals are called

Populations of animals are often limited by the amount of food.

animals that predators eat are called

predators

prey

Predators are adapted to catching and consuming their prey.

Predator and prey aadaptations

Prey have adaptations to detect and prevent being eaten by predators.

camouflage

mimicryvenomous coral

snakescarlet

kingsnakespeed &

keen senses

warning colors & patterns

Prey Adaptations – GeneralPrey have adaptations to detect and prevent being eaten by predators.

Predator Adaptations – General

Predators have adaptations to catch and consume their prey.

birds of prey have keen

eyesight and sharp beaks and

talons

venomous snakes have poisonous venom to subdue their preycamouflage

allows predators to blend in with

their surroundings

kingsnakes are

immune to the

venom of venomous snakes

treefrogs have special pads on their feet so they can cling to

vertical surfaces

Predator–prey graph

There are always more prey than predators.The prey always increases before the predators do.

Predator–prey graphThis population data comes from fur trapping records. How are the populations linked?

Predator–prey graphHow does the lynx population depend on the number of snowshoe hares?

0

50

esti

mate

d p

op

ula

tion

siz

e

(th

ou

san

ds)

1800 1820 1840 1860 1880 1900

100

150

lynx

snowshoe hare

time (year)

Take a closer look at this part

of the graph.

Predator–prey graph sectionWhy does the peak for the lynx population always come after the peak

for the number of snowshoe hares?

0

50

esti

mate

d p

op

ula

tion

siz

e

(th

ou

san

ds)

1850 1855 1860 1865

100

150

lynx

snowshoe hare

time (year)

For the populations to survive, there will always be more hares

than lynxes.

Predator and prey population sizes follow a cycle.What happens if the prey population increases?

normal prey populationprey population

increasesprey population

increases

predator population increases

as more food

predator population decreases

as less food

prey population decreasesbecause of more predators

Predator–prey cycle

Predator and prey population sizes follow a cycle.What happens if the prey population decreases?

normal prey population

Predator–prey cycle

prey population increasesbecause of less predators

prey population decreases

predator population increases

as more food

predator population decreases

as less food

prey populationdecreases

PREDATION

• is when an individual of one species (predator) eats all or most of an individual of another species (prey).• An everyday occurrence in nature.

Bellwork 11/10

1. Explain what a population is2. Explain predator prey relationships (be sure to talk

about the graph)

Populations change over time:

Limiting Factors in an Ecosystem

Limiting FactorsEnvironmental factors (either biotic or abiotic)

that prevent a population from increasing

Availability of Food• basic need of all organisms to obtain energy from the

environment• If food is not available, organisms may not reproduce

and/or may starveWater• The right quantity and quality of water is a basic need

of all organismsShelter• A basic need of all organisms to find a suitable place

to take refuge from the weather, to hide from predators, to sleep, to raise young, etc.

• Shelter may be biotic (like trees), abiotic (like rocks), and/or man-made (like houses)

Space• A basic need of all organisms to have a certain

amount of space • Must be large enough to meet organism’s basic

requirements such as finding food, water, shelter, mates, etc.

Predation• An organism preys on and consumes animalsDisease• Viral, bacterial, and fungal infections and infected

wound sites may negatively impact organismsHabitat Destruction• Loss of habitat through climate change, urbanization,

and other factors

Populations change over time: Carrying Capacity

Bellwork 11/12/14

1. Explain what a limiting factor is2. Give 4 examples of limiting factors3. Explain how limiting factors effect animal populations.

Carrying Capacity

Carrying capacity is the largest population that an area can support• Maintaining a balance

https://www.youtube.com/watch?v=QI2ixJeIxEU

Carrying Capacity • Carrying capacity is determined by

limiting factors (both abiotic and biotic) • Limiting factors can include: number of

predators, amount of rain, temperature, amount of food, and disease.

• These factors are based on• Location• Time • Short term ~ seasonal changes• Long-term ~global changes in factors

such as climate• Technology

Bellwork 11/13/14

1. What is carrying capacity?2. How does carrying capacity effect a population?

Populations change over time: Ecologic Succession

Learning Target: I will be able to explain how populations in an area take over an environment• Succession is the gradual process by which ecosystems

change and develop over time• The change in an ecosystem that happens when one

community replaces another as a result of changing biotic and abiotic factors

• Ecological Succession: Primary• The establishment of a community in an area of exposed rock

that does not have topsoil is called Primary Succession.• It occurs very slowly at first

• Ecological Succession: Primary• The first organisms to arrive are usually lichens

or mosses, which are called pioneer species.• They secrete acids that can break down rock• Their dead, decaying organic materials, along with

bits of sediment from the rock make up soil.

• Ecological Succession: Primary• Small weedy plants and other organisms become established.• As these organisms die, additional soil is created

• Ecological Succession: Primary• Seeds brought in by animals, water and wind begin to grow in

the soil.• Eventually enough soil is present for shrubs and trees to grow.

• Ecological Succession: Primary• The stable, mature community that eventually develops from

bare rock is called a climax community.

• Ecological Succession: Secondary• Disturbances (fire, flood, windstorms) can disrupt a

community.• After a disturbance,

new species of plants and animals might occupy the habitat.

• Ecological Succession: Secondary• Pioneer species in secondary succession are usually plants

that begin to grow in the disturbed area.• This is much faster

than primarysuccession

• Ecological Succession: End point?• Cannot be predicted• Different rates of growth &

human involvementmake it impossible toknow if a true climaxcommunity has beenreached.

• http://www.schooltube.com/video/51a9a5aaf99f43e1830b/Chernobyl--Showing%20Succession

• http://www.youtube.com/watch?v=4RsMyVavT2Q

Conservation Biology

Conservation biology is the study of how to protect biodiversity.

Endangered, Threatened, and Extinct SpeciesA threatened species is a species that could become endangered in the near future. An endangered species are species that are in danger of becoming extinct in the near future

http://oceantoday.noaa.gov/endspeciesday/welcome.htmlExtinction is the disappearance of all members of a species from Earth http://www.youtube.com/watch?v=34ru-NECVEA

Habitat Loss

• If a habitat is destroyed or disrupted, the native species might have to relocate or they will die.• Destruction of habitat - such as the clearing of tropical

rainforests, has a direct impact on global biodiversity.• Disruption of habitat - the declining population of one

species can affect an entire ecosystem.