Transcript Slide 1
IMPACTS ON BIODIVERSITY Michaelis Overfishing and Overhunting One threat to biodiversity occurs when collapse humans cause ecosystems to ____________ by using too many natural resources or taking keystone species away a ______________________. Overfishing and Overhunting Keystone species An organism that is ____________________: necessary for keeping an ecosystem in balance _____________. Example: Sea Otter Overfishing and Overhunting Facts: blubber Only marine mammal without ___________... Overfishing and Overhunting How do they stay warm in the cold ocean? Otters have the densest fur ____________________ fur of any mammal. Fur is so thick that their skin never gets wet when they swim: 400,000 hairs per square ___________ centimeter. Overfishing and Overhunting During the fur trade humans hunted otters almost to extinction for their _____________ thick warm pelts ____________________. By 1911 the sea otter population had dropped to roughly 1,000 individuals. Overfishing and Overhunting Sea Otter’s Niche: sea urchins Eats _______________. rocks and shells to break open Uses ___________________ sea urchins. Overfishing and Overhunting Sea Otter’s Niche: sharks and humans Predators: _____________________________ seaweed to anchor Uses ________________________ themselves while they eat and sleep. How Sea Otters Keep Their Ecosystem in Balance sea urchin population down Otters keep the ___________________________. Sea urchins eat away at the _______ base of sea weed. Fish and other sea life rely on the sea weed food and shelter forests for _____________________________. Overhunting Keystone Species: How do you think the decreasing otter population affects the ocean ecosystem? Otter population is DOWN increases Sea Urchin Population = ______________ decreases Sea Weed Population = _______________ Fish Population = ____________________ decreases Seal Population = ____________________ decreases Orca Population = ____________________ decreases Overhunting Keystone Species: What are the long term implications on the food web in this situation? Urchin Barrens Biological Magnification When carnivores eat herbivores that have contaminated with pollution been _________________________________. Causes concentrations of harmful substances to ___________________________________. accumulate in higher trophic levels Biological Magnification Class Demonstration ppm of In this demo assume that 100 __________ pollutant will cause this animal to: die ___________ Make them ___________ sterile unhealthy Make them very ______________ Biological Magnification Class Demonstration How many parts per million does the guppy have? How many parts per million does the salmon have? How many parts per million does the eagle have? Biological Magnification Class Demonstration 1. What type of organisms are affected the most by biological magnification? 1. How do you think biodiversity will be affected? Invasive Species Species that are brought to an ecosystem by harm the ecosystem humans and _________________________ do not have any natural predators because they ______________________________. Invasive Species 50,000 _______________ exotic species live in the U.S. $130 billion per year spent to help undo _____________________ the damage they cause nearly half Invasive species also threaten _____________ of the species currently protected under the Endangered Species Act ________________________ Kudzu in Alabama Zebra Mussels Invasive Species – Burmese Python, Florida Introduced Beavers - Tierra Del Fuego, South America Cane Toad Video Invasive Species Rats in Hawaii Example: ___________________________ I’iwi Birds are ________________. native to Hawaii They are an ________________________. endangered species face I’iwi are one of many Hawaiian Birds that _____ extinction due to invasive species. __________________________________ Hawaii Invasive Species Hawaii Invasive Species Video Invasive Species Questions: How do you think rats harm the I’iwi bird population? Why do you think the rat population does so well in Hawaii?