Characteristics of Population--Characteristics of Population--Population SizePopulation Size

• The number of individuals in the The number of individuals in the population is the population’s size. population is the population’s size.

• If a population is small and made up of If a population is small and made up of organisms that do not move, the size can organisms that do not move, the size can be determined by counting the be determined by counting the individualsindividuals.

• Usually individuals are too widespread or Usually individuals are too widespread or move around too much to be counted. The move around too much to be counted. The population size then is estimated. population size then is estimated.

• The size of human population is The size of human population is increasing each year. increasing each year.

• The size of a population is always The size of a population is always changing. The rate of change in changing. The rate of change in population size varies from population to population size varies from population to population.population.

Population DensityPopulation Density• The number of individuals in a population The number of individuals in a population

that occupy a definite area is called that occupy a definite area is called population densitypopulation density. .

• When more individuals live in a given When more individuals live in a given amount of space the population is more amount of space the population is more dense. dense.

Population SpacingPopulation Spacing

• Another characteristic of populations is Another characteristic of populations is spacing, or how the organisms are spacing, or how the organisms are arranged in a given area. arranged in a given area.

• They can be evenly They can be evenly spaced, randomly spaced, spaced, randomly spaced, or clumped together. or clumped together.

Limiting FactorsLimiting Factors

• All ecosystems have a limited amount of All ecosystems have a limited amount of food, water, living space, mates, nesting food, water, living space, mates, nesting sites, and other resources. sites, and other resources.

• A A limiting factor limiting factor is any biotic or abiotic is any biotic or abiotic factor that limits the number of factor that limits the number of individuals in a population.individuals in a population.

Limiting FactorsLimiting Factors• Competition is the struggle among Competition is the struggle among

organisms to obtain the same resources organisms to obtain the same resources needed to survive and reproduce. needed to survive and reproduce.

• As population density increases, so does As population density increases, so does competition among individuals for the competition among individuals for the resources in their environment. resources in their environment.

Carrying CapacityCarrying Capacity

• Carrying capacity is the largest number of Carrying capacity is the largest number of individuals of a species that an individuals of a species that an environment can support and maintain for environment can support and maintain for a long period of time. a long period of time.

• If a population gets bigger than the If a population gets bigger than the carrying capacity of the environment, carrying capacity of the environment, some individuals are left without some individuals are left without adequate resources. adequate resources.

Biotic PotentialBiotic Potential• The maximum rate at which a population The maximum rate at which a population

increases when plenty of food and water increases when plenty of food and water are available, the weather is ideal, and no are available, the weather is ideal, and no diseases or enemies exist, is its biotic diseases or enemies exist, is its biotic potential.potential.

• Most populations never reach their biotic Most populations never reach their biotic potential, or they do so for only a short potential, or they do so for only a short period of time. period of time.

• Eventually, the carrying capacity of the Eventually, the carrying capacity of the environment is reached and the environment is reached and the population stops increasing. population stops increasing.

Symbiosis and Other InteractionsSymbiosis and Other Interactions

• SymbiosisSymbiosis (sihm bee OH sus) is any close (sihm bee OH sus) is any close interaction between two or more different interaction between two or more different species. species.

• Mutualism is a symbiotic relationship in Mutualism is a symbiotic relationship in which two different species of organisms which two different species of organisms cooperate and both benefit. cooperate and both benefit.

Symbiosis and Other InteractionsSymbiosis and Other Interactions

• Commensalism is a form of symbiosis Commensalism is a form of symbiosis that benefits one organism without that benefits one organism without affecting the other organism. affecting the other organism.

• Parasitism is a symbiotic relationship Parasitism is a symbiotic relationship between two species in which one species between two species in which one species benefits and the other species is harmed. benefits and the other species is harmed.

PredationPredation• Predation is the act of one organism Predation is the act of one organism

hunting, killing, and feeding on another hunting, killing, and feeding on another organism. organism.

• Owls are predators of Owls are predators of mice. mice.

• Mice are their prey. Mice are their prey.

PredationPredation

• Predators are biotic factors that limit the Predators are biotic factors that limit the size of the prey population. size of the prey population.

• Availability of prey is a biotic factor that Availability of prey is a biotic factor that can limit the size of the predator can limit the size of the predator population. population.

Habitats and NichesHabitats and Niches

• The role, or job, of an organism in the The role, or job, of an organism in the ecosystem is called its ecosystem is called its nicheniche (NICH). (NICH).

• What a species eats, how it gets its food, What a species eats, how it gets its food, and how it interacts with other organisms and how it interacts with other organisms are all parts of its niche. are all parts of its niche.

• The place where an organism lives is The place where an organism lives is called its called its habitathabitat. .

True or False Change to Make TrueTrue or False Change to Make True1. Predators are 1. Predators are abioticabiotic factors that limit the factors that limit the

size of prey populations size of prey populations

3. An 3. An ecosystemecosystem is a large region with plant is a large region with plant and animal groups well adapted to the soil and animal groups well adapted to the soil and climate of the regionand climate of the region

4. The number of individuals living in a 4. The number of individuals living in a definite area is called population definite area is called population spacingspacing

F biotic2. Groups of populations that interact with 2. Groups of populations that interact with each other in s given area form a each other in s given area form a communitycommunity TrueTrue

F biomeF biome

F densityF density

CompletionCompletion5. Environmental factors that include soil, sunlight, air ______

6. Made of overlapping food chains ___________ food web

population7. Number of one species in an area _________8. Sometimes environmental factors reach a carrying ___________capacity

abiotic

CompletionCompletion9. A relationship in which one species A relationship in which one species benefits at the expense of another ________benefits at the expense of another ________

10. Role of an organism in an ecosystem10. Role of an organism in an ecosystemnicheniche

parasitismparasitism

Completion select best choiceCompletion select best choice

11. Groups of populations that interact with 11. Groups of populations that interact with each other in a given area form each other in a given area form a__________a__________ communitycommunity, niche, niche

12. The struggle among organisms to 12. The struggle among organisms to obtain resources for reproduction and obtain resources for reproduction and survival is called ___________ survival is called ___________

competitioncompetition, capacity, capacity

Completion select best choiceCompletion select best choice

13. A symbiotic relationship that benefits 13. A symbiotic relationship that benefits both species is called __________both species is called __________

commensalism,commensalism, mutualismmutualism

14. The physical location where an 14. The physical location where an organism lives is its ______organism lives is its ______

habitathabitat ,population,population

MatchingMatchingA. Living things grow and developA. Living things grow and developAAB. Living things respondB. Living things respondC. Living things maintain homeostasisC. Living things maintain homeostasisD. Living things use energyD. Living things use energyE. Living things are organizedE. Living things are organizedF. Living things reproduceF. Living things reproduceFF

15. __ The fish in the classroom aquarium 15. __ The fish in the classroom aquarium have baby fish have baby fish 16. __ Your neighbor’s puppy has grown 16. __ Your neighbor’s puppy has grown into a large doginto a large dog17. __ Your friend has 2 brothers and a 17. __ Your friend has 2 brothers and a sistersister

FF

Match each item with the correct statementMatch each item with the correct statement A. EcologyA. Ecology

B. Limiting factorB. Limiting factorC. Carrying capacityC. Carrying capacity ProducersProducersE. Nitrogen fixationE. Nitrogen fixationF. EnergyF. Energy

G. Biotic factorsG. Biotic factors PredationPredationI. AirI. AirJ. Abiotic factorsJ. Abiotic factors

K. MutualismK. MutualismL. WaterL. Water

18. ___18. ___ symbiotic relationship that benefits symbiotic relationship that benefits both speciesboth species19. ___19. ___ living organismsliving organisms

20. ___ limits the number of organisms in 20. ___ limits the number of organisms in an environmentan environment

D.

H.

D.D.D.D.KK

GGBB

Match each item with the correct statementMatch each item with the correct statement A. EcologyA. Ecology

B. Limiting factorB. Limiting factorC. Carrying capacityC. Carrying capacity ProducersProducersE. Nitrogen fixationE. Nitrogen fixationF. EnergyF. Energy

G. Biotic factorsG. Biotic factors PredationPredationI. AirI. AirJ. Abiotic factorsJ. Abiotic factors

K. MutualismK. MutualismL. WaterL. Water

21. ___21. ___ The 1The 1stst level of the food chain level of the food chain22. ___22. ___ One organism kills and feeds on One organism kills and feeds on another organism.another organism.23. ___ the largest number of organisms 23. ___ the largest number of organisms that an environment can support and that an environment can support and maintainmaintain

D.

H

D.D.DDCC

Match each item with the correct statementMatch each item with the correct statement A. EcologyA. Ecology

B. Limiting factorB. Limiting factorC. Carrying capacityC. Carrying capacity

D. Biotic factorsD. Biotic factorsE PredationE Predation

24.___number of individuals in a population24.___number of individuals in a population

25.___number of individuals that occupy a 25.___number of individuals that occupy a definite area populationdefinite area population

28 ___ arrangement of organisms in an area28 ___ arrangement of organisms in an area

ECC

AA

26.___maximum rate of population increase26.___maximum rate of population increase

27.___reduces the number in the population27.___reduces the number in the population

DB