Population Dynamics Carrying Capacity within Ecosystems 9 th

Population Dynamics & Carrying Capacity within Ecosystems 9 th Grade Biology Ms. Kallestad

Lecture Objective: Lecture Objectives & Standards Students will be able to understand carrying capacity and the limits of population growth within ecosystems. Students will demonstrate the ability to construct population growth models. Students will access prior knowledge to develop an understanding for content. Content Standard(s): HS-LS 2 -1. Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales HS-LS 2 -2. Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales.

Discuss in a Think-Pair. Share! What do you think would happen if there were no factors controlling population size? How would that affect access to resources? Recall population: All of the organisms in the same group or species that live in a particular area Human population Educational Hook

Accessing prior knowledge, recall the levels of biological organization as shown below. Discuss each level with a pairshare partner. Ecosystem Levels of Biological Organization Community Population Species Individual Smart. Art

What is Carrying Capacity? Carrying Capacity: The size of a population that can be supported by an ecosystem upon the available resources and services of that ecosystem. Notice in the graph above that the number of individuals remains relatively close to the carrying capacity of this ecosystem. Why do you think this happens? Dual Coding

Cyclical oscillations are repeating rises and drops in the population size over time Usually hovers around carrying capacity Population Cycles and Fluctuations Visual Aid

General pattern of an interaction between predator and prey Predator-Prey Relationship Why does the interaction graph follow this trend between predator and prey? Visual Aid

Every ecosystem includes a limiting factor which constraints or “limits” a population size and slows it or stops it from growing. Water Food So, how DO population sizes remain level? Limiting Factors Climate & Weather Space Limiting factors = increase in competition: individuals and populations fighting each other for available resources Interspecific competition: between individuals of different species Intraspecific competition: between individuals within the same species Dual Coding/Smart Art

A limiting factor that affects the population size through increasing or decreasing birth and death rates Change how they affect the population when the population changes in size Directly related to the density of the population…or the density is dependent on this factor Density. Dependent Limiting Factor Competition for Space Predation Infection Disease Are you noticing a trend? Dual Coding/Visual Aids

Factors that exert their influences on population size regardless of the density of the population Always affect the population the same, regardless of the population size Density. Independent Limiting Factor Temperature & Climate Natural Disasters Pollution What trends do you notice here? Dual Coding/Visual Aids

Now You Try! Accessing the knowledge you have gained so far about density-dependent and densityindependent factors, construct a compare and contrast chart (or Venn-diagram) about these two limiting factors. Discuss your charts with an elbow partner and save your charts to be used as exit-slips. Progress Monitoring

Food as a Limiting Factor Insufficient amounts lead to death through starvation Some animals emigrate due to lack of Organisms relying on one type of food are severely affected Visual Aid

Water as a Limiting Factor Leads to death via dehydration Animals will emigrate Drought conditions pose threats for those not adapted to low water conditions Visual Aid

Climate & Weather as a Limiting Factor Temperature changes will affect plants and animals Floods and droughts cause destruction of habitats and death in organisms Visual Aid

Limited space = limited shelter. Without proper shelter, predators can diminish populations quickly Space as a Limiting Factor Developments like houses and buildings further limit ecological space Increase in populations lessen available space in the habitat Visual Aid

Your turn to discuss! Which density-dependent or density-independent factor do you think has the fastest effect on any ecosystem of the same size? Discuss in a think-pair-share Progress Monitoring

Types of relationships within or between species: 1. Competition: Limited by resource availability, so organisms must compete against one another to obtain those resources. Species Interactions 2. Predation: Members of one species (predator) consume members of another species(prey) 3. Commensalism: Interaction where one species benefits and another neither benefits nor is harmed Dual Coding & Visual Aids

Types of relationships within or between species: Species Interactions (cont. ) 4. Mutualism: Symbiosis that is beneficial to both organisms involved 5. Parasitism: Relationship where one organism (parasite) lives on or in another organism (host), causing it some harm. Dual Coding & Visual Aids

With your pair share partner, complete the table with a (+) sign for positive, a (-) sign for negative , or (0) for neutral in each column. Now You Try! Interaction Species 1 Species 2 Mutualism Parasitism Competition Commensalism Predation Progress Monitoring/ Smart Art or Table

Carrying capacity logistic growth curve Predator & Prey relationship: cyclical oscillation curve Limiting factors Recall the Big Ideas Density dependent (usually biotic) Density independent (usually abiotic) Species interactions Competition (+, -) depending on outcome Predation (+, -) Commensalism (+, 0) Mutualism (+, +) Parasitism (+, -)

Now You Try! Draw out an example of one species interactions on a half sheet of blank paper. Once your drawing is completed, write a caption guided towards how these organisms might experience limiting factors in an ecosystem. Place your drawing with the caption on the appropriate “Big Paper” posted around the classroom. Culminating Activity/Question

This presentation information was guided by the following websites: https: //education. seattlepi. com/five-types-ecologicalrelationships-4019. html https: //betterlesson. com/lesson/635604/limiting-factors-andmodels-of-population-growth-1 -of-2? from=cc_lesson References http: //www 2. nau. edu/lrm 22/lessons/population_growth/populati on_growth. html https: //www. khanacademy. org/science/biology/ecology/populati on-growth-and-regulation/a/mechanisms-of-populationregulation