POPULATION DYNAMICS….7billion & Counting Essential Questions What are the factors that affect population growth? What are some of the effects that overpopulation can have on an environment? Essential questions are the point of the lesson, so it can be presented to the class to develop curiosity and initiate content comprehension. The presentation should be revisited at the end of the lesson to assess sufficient understanding of topic at hand through class discussion and student notes modification. Encourage taking notes. http://en.wikipedia.org/wiki/Paul_R._Ehrlich#mediaviewer/File:2008_Summer_Olympics_torch_relay,_Shenzen.jpg Steve Jerveston CC BY 2.0

LEVELS OF ORGANIZATION biome group of organs working together group of different kinds of tissues working together one individual living thing all interacting populations in an ecosystem large region with characteristic plants and animals that includes several ecosystems all living and nonliving things interacting within a certain area all organisms of the same kind living in one area group of similar cells organized to work together smallest unit of living things ecosystem community population organism organ system organ Population Dynamics tissue cell

Populations in Ecosystems Vocabulary Abiotic Factors – Non-living components of an area (rocks, weather, sunlight, etc.). Biotic Factors – Living organisms as well as the products of living organisms. Carrying Capacity – The maximum size of a population that can be sustained by any given ecosystem. Ecosystem – Living and non-living factors interacting within a specific area. Organism – A living thing. Ask students to provide examples of each verbally.

Populations in Ecosystems Vocabulary Environment – The area around an organism including living and nonliving things. Limiting Factor – Any biotic or abiotic factor that controls population size. Population – All of the interacting individuals of one species in a given area. Birth Rate – Number of individuals born per 1000 individuals in a population. Death Rate – Number of individuals that died per 1000 individuals in a population. Ask students to provide examples/scenarios of each verbally.

How populations change in size over time – four major factors Population Dynamics How populations change in size over time – four major factors Birth Rate: (number of live births per 1000 individuals) How can the birth rate affect population size? Death Rate (number of deaths per 1000 individuals) How can the death rate affect population size? Immigration: (movement into an area) How can immigration affect population size? Emigration: (movement out of an area) How can emigration affect population size? Ask the question for each : How does that affect population size?

- Population Size What goes up must come down •Increases in population: through birth or immigration •Decreases in population: through death or emigration. Change in Population Birth Rate + Immigration - Death Rate + Emigration =

Logistic or Exponential Growth Curve? Can you think of something in nature that exhibits exponential growth? Logistic growth? Populations will follow two general paths: When faced with unlimited resources, it will grow exponentially. When faced with limited resources, it will grow logistically. “Boom and Bust” “Boom then Stable” Ask students to identify which graph represents each population ‘path’. Ask “Why?” when they give their answers. https://www.boundless.com/biology/population-and-community-ecology/environmental-limits-to-population-growth/exponential-growth/ CC By 3.0

Logistic Growth Can you think of some resources that could limit population growth? Characterize these resources as abiotic or biotic. Populations grow rapidly with ample resources (biotic potential), but as resources become limited (environmental resistance), population growth rate slows and levels off. Carrying Capacity (K) is the maximum number of organisms that an area can support for longer lengths of time.

Exponential and Logistic Population Growth: J-Curves and S-Curves As a population levels off, it often fluctuates slightly above and below the carrying capacity.

Check out the link below for a great video on the topic! Overpopulation Video By the year 2020, 9 to 10 billion humans are expected to inhabit the planet. Do you think the world is overpopulated? Check out the link below for a great video on the topic! http://overpopulationisamyth.com/ Click play on the video to show the students the “idea” of overpopulation is not an overall agreed upon view.