SB5a. Plan and carry out investigations to analyze data to support explanations about factors affecting biodiversity and populations in ecosystems. SB5e. Construct an argument to predict an organism’s ability to survive within changing environmental limits (e.g., temperature, pH, drought, fire).  SB6d. Develop and use mathematical models to support explanations of how undirected genetic changes in natural selection and genetic drift have led to changes in populations of organisms.  Learning Targets: 1.5 I can define biodiversity and speciation 1.6 I can analyze and interpret data to explain patterns in biodiversity that result from speciation via reproductive isolation 1.7 I can recognize that undirected genetic changes have led to changes in populations of organisms. 1.8 I can identify mathematical models that can be used to support explanations of how undirected genetic changes have led to changes in populations of organisms. 1.9 I can develop and use mathematical models to support explanations of how undirected genetic changes have led to changes in populations of organisms. 1.14 I can predict an organism’s ability to survive within changing environmental limits.

Where did all these different organisms come from? SB5a., SBe. Biodiversity The total variety of all the organisms in the biosphere = ________________ Where did all these different organisms come from? How are they related? BIODIVERSITY

The evolution of sexual reproduction led to increased diversity. SB5a., SB5e. Biodiversity The evolution of sexual reproduction led to increased diversity. Genetic variation is an advantage of sexual reproduction. Sexual reproduction may have led to the evolution of multicellular life. Multicellular meaning made of many cells. Single celled organisms evolved first, and gave rise to multicellular organisms

Biodiversity and Ecosystems SB5a., SB5e. Biodiversity Biodiversity and Ecosystems There are 3 types of biodiversity: Ecosystem diversity Species diversity Genetic diversity Biodiversity can influence an ecosystem’s stability, productivity, and value to humans. Tell students: The number and variety of species in an ecosystem can influence that ecosystem. Click to reveal the ways biodiversity can influence the ecosystem. Explain that biodiversity influences an ecosystem’s stability, productivity, and value to humans. Click to reveal a statement about keystone species. Ask for a volunteer to complete the sentence. Click to reveal the correct answer. Tell students: Sometimes the presence or absence of a single keystone species, like the sea otter shown, can completely change an ecosystem. Explain that the sea otter is a keystone species. When the otter population falls, the population of its favorite prey, sea urchins, goes up. Population increases in sea urchins, in turn, cause a dramatic decrease in the population of sea kelp, the sea urchin’s favorite food. Ask: What might be the impact of a decrease in sea kelp? Answer: There might be a decrease in the number of fish that thrive in kelp forests and a decrease in the animals that eat those fish. Point out that healthy and diverse ecosystems play a vital role in maintaining soil, water, and air quality. Explain that genetic diversity within species provides variations that can make it possible for populations to change over time as their environments change. The presence or absence of a single keystone species can completely change an ecosystem.

Biodiversity and Ecosystems SB5a., SB5e. Biodiversity Biodiversity and Ecosystems Threats to Biodiversity Altered habitats Hunting Invasive species Pollution in food webs Climate change Explain to students that scientists estimate that more than 99 percent of the species that have ever lived are now extinct. So extinction is not new. But human activity today is causing the greatest wave of extinctions since dinosaurs disappeared. Ask: What are the most significant threats to biodiversity? Answer: Humans reduce biodiversity by altering habitats, hunting, introducing invasive species, releasing pollution into food webs, and contributing to climate change. Explain that when natural habitats are eliminated for agriculture or development, species in those habitats become extinct. But habitats don’t need to be completely destroyed to put species at risk. Development often splits ecosystems into pieces, a process called habitat fragmentation, leaving habitat “islands.” Click to reveal the picture of a biological island. Tell students: A biological island can be any patch of habitat surrounded by a different habitat, as shown in this picture. Explain that deforestation for housing developments in Florida has led to the pattern of forest “islands” shown here. Tell students: The smaller a habitat island is, the smaller the number of species that can live there and the smaller the populations of those species the island can support. Both these kinds of environmental changes impact ecosystem stability by increasing vulnerability to other kinds of disturbance. Pictures-lionfish, zebra mussel, crayfish covered in zebra mussels.

Biodiversity and Ecosystems SB5a., SB5e. Biodiversity Biodiversity and Ecosystems Genetic diversity includes all the different forms of genetic information carried by a particular species. Within each species, genetic diversity refers to the total of all different forms of genes present in that species. Genetic diversity is the “raw material” that enables organisms to adapt to changing environments. Genetic diversity within species provides variations that can make it possible for populations to change over time as their environments change. Tell students: The number and variety of species in an ecosystem can influence that ecosystem. Click to reveal the ways biodiversity can influence the ecosystem. Explain that biodiversity influences an ecosystem’s stability, productivity, and value to humans. Click to reveal a statement about keystone species. Ask for a volunteer to complete the sentence. Click to reveal the correct answer. Tell students: Sometimes the presence or absence of a single keystone species, like the sea otter shown, can completely change an ecosystem. Explain that the sea otter is a keystone species. When the otter population falls, the population of its favorite prey, sea urchins, goes up. Population increases in sea urchins, in turn, cause a dramatic decrease in the population of sea kelp, the sea urchin’s favorite food. Ask: What might be the impact of a decrease in sea kelp? Answer: There might be a decrease in the number of fish that thrive in kelp forests and a decrease in the animals that eat those fish. Point out that healthy and diverse ecosystems play a vital role in maintaining soil, water, and air quality. Explain that genetic diversity within species provides variations that can make it possible for populations to change over time as their environments change.