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Pretest Unit 3: Population Ecology 1.What is a population and how do ecologists study it 2.Explain the difference between a niche and habitat 3.Explain.

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Presentation on theme: "Pretest Unit 3: Population Ecology 1.What is a population and how do ecologists study it 2.Explain the difference between a niche and habitat 3.Explain."— Presentation transcript:

1 Pretest Unit 3: Population Ecology 1.What is a population and how do ecologists study it 2.Explain the difference between a niche and habitat 3.Explain the predator/prey relationship and carrying capacity on the graph. 4.Explain why animals fight 5.Explain how certain factors limit a population 6.Explain animal extinction and how it affects an area 7.What is succession and how does it occur?


3 Species, Populations, Community, and sampling LT: Organisms occupy a specific area

4 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.

5 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

6 Bellwork` 10/30 1.What are three things we learned about yesterday? You must have a sentence about each one

7 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

8 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 7 th graders does not accurately represent all students in the school. Example 1: A 7 th grade homeroom was surveyed to determine how many texts students at Olean Intermediate Middle School send each day.

9 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.

10 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

11 Population changes affect communities As population in one species declines, other species may appear Human development now displaces other species and threatens biodiversity

12 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.

13 Habitat and Niche Notes LT: Organisms occupy a specific area

14 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

15 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


17 Predator and Prey Interactions

18 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

19 Population Size A concept map of what effects the size of a population. POPULATION SIZE Food plenty of food population grows food shortage population falls Diseaseovercrowding increased aggression / competition for resources increase in predators Decrease in predators Predators

20 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

21 Predators are adapted to catching and consuming their prey. Predator and prey aadaptations Prey have adaptations to detect and prevent being eaten by predators.

22 camouflage mimicry venomous coral snake scarlet kingsnake speed & keen senses warning colors & patterns Prey Adaptations – General Prey have adaptations to detect and prevent being eaten by predators.

23 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 prey camouflage 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

24 Predator–prey graph There are always more prey than predators. The prey always increases before the predators do.

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

26 Predator–prey graph How does the lynx population depend on the number of snowshoe hares? 0 50 estimated population size (thousands) lynx snowshoe hare time (year) Take a closer look at this part of the graph.

27 Predator–prey graph section Why does the peak for the lynx population always come after the peak for the number of snowshoe hares? 0 50 estimated population size (thousands) lynx snowshoe hare time (year) For the populations to survive, there will always be more hares than lynxes.

28 Predator and prey population sizes follow a cycle. What happens if the prey population increases? normal prey population prey population increases prey population increases predator population increases as more food predator population decreases as less food prey population decreases because of more predators Predator–prey cycle

29 Predator and prey population sizes follow a cycle. What happens if the prey population decreases? normal prey population Predator–prey cycle prey population increases because of less predators prey population decreases predator population increases as more food predator population decreases as less food prey population decreases

30 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.

31 Bellwork 11/10 1.Explain what a population is 2.Explain predator prey relationships (be sure to talk about the graph)

32 Populations change over time: Limiting Factors in an Ecosystem

33 Limiting Factors Environmental factors (either biotic or abiotic) that prevent a population from increasing

34 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 starve Water The right quantity and quality of water is a basic need of all organisms Shelter 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)

35 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 animals Disease Viral, bacterial, and fungal infections and infected wound sites may negatively impact organisms Habitat Destruction Loss of habitat through climate change, urbanization, and other factors

36 Populations change over time: Carrying Capacity

37 Bellwork11/12/14 1.Explain what a limiting factor is 2.Give 4 examples of limiting factors 3.Explain how limiting factors effect animal populations.

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

39 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

40 Bellwork 11/13/14 1.What is carrying capacity? 2.How does carrying capacity effect a population?

41 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

42 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

43 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.

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

45 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.

46 Ecological Succession: Primary The stable, mature community that eventually develops from bare rock is called a climax community.

47 Ecological Succession: Secondary Disturbances (fire, flood, windstorms) can disrupt a community. After a disturbance, new species of plants and animals might occupy the habitat.

48 Ecological Succession: Secondary Pioneer species in secondary succession are usually plants that begin to grow in the disturbed area. This is much faster than primary succession

49 Ecological Succession: End point? Cannot be predicted Different rates of growth & human involvement make it impossible to know if a true climax community has been reached.

50 nobyl--Showing%20Succession nobyl--Showing%20Succession

51 Conservation Biology Conservation biology is the study of how to protect biodiversity.

52 Endangered, Threatened, and Extinct Species A 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 Extinction is the disappearance of all members of a species from Earth

53 Habitat Loss

54 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.

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