Bell Ringer – AP Practice 1) The largest amount of energy available in the pyramid is the… a) phytoplankton b) bass c) perch d) water flea e) both A and B Bell Ringer – AP Practice 2) What food chain is represented in the diagram? a) Water flea perch bass phytoplankton b) Perch bass phytoplankton c) phytoplankton bass perch water flea d) phytoplankton water flea perch bass e) phytoplankton water flea perch bass Bell Ringer – AP Practice 3) According to the 10% rule, to support 100 pounds of bass requires … a) 100 pounds of perch b) 90 pounds of perch c) 1000 pounds of water fleas d) 10,000 pounds of water fleas e) 900,000 pounds of phytoplankton AP Practice 4) Carbon dioxide is being added to the Earth’s atmosphere in all of the following ways except… a) combustion of fossil fuels b) cellular respiration c) volcanism d) decomposition of dead organic matter e) photosynthesis Keystone and Invasive Species pgs 151-154, 158-160 Keystone Species • Keystone Species – a species that exerts greater influence upon an ecosystem than do others species found therein. Keystone Species • Keystone Species – a species that exerts greater influence upon an ecosystem than do others species found therein. • Keystone species tend to have a strong or wide -reaching impact out of proportion to their abundance within the ecosystem. Why Keystone? • A keystone is found at the top of an arch; without a keystone, the arch would collapse. • Likewise, the removal of a keystone species will have greatly alter energy movement within the ecosystem. Identifying Keystones • Consumers near the top of food chains are often keystone species. Identifying Keystones • Consumers near the top of food chains are often keystone species. • Predators at high trophic levels can indirectly promote populations of organisms at lower trophic levels by keeping species at intermediate trophic levels in check – this phenomenon is known as a trophic cascade . Trophic Cascade • In a trophic cascade, the population of plants is closely tied to the population of toads. Trophic Cascade • In a trophic cascade, the population of plants is closely tied to the population of toads. • Without toads, the grasshopper population would greatly increase, causing damage to the native plant populations. Trophic Cascade • In a trophic cascade, the population of plants is closely tied to the population of toads. • Without toads, the grasshopper population would greatly increase, causing damage to the native plant populations. • With the toad present, though, the grasshopper population is kept in check, promoting the growth of plants. Another Keystone Species Example page 156 1) Explain how the sea otter population vastly affects sea kelp population. 2) What predator began lowering sea otter populations? Explain why this predator began targeting sea otters. 3) Draw a complete food chain for this ecosystem (include kelp, urchins, otters and orcas) 4) If human actions could help reestablish populations of great whales, how would this affect the populations of otters, urchins and kelp? Exotic and Invasive Species • Exotic species – a non-native species introduced into an ecosystem • Invasive species – an exotic species which spreads quickly, dominating and vastly affecting an ecosystem. Exotic and Invasive Species • Exotic species – a non-native species introduced into an ecosystem • Invasive species – an exotic species which spreads quickly, dominating and vastly affecting an ecosystem. • Species become invasive because limiting factors (such as predators, parasite and competition) found in their original habitats are not present in their new ecosystems. Exotic and Invasive Species • Exotic species – a non-native species introduced into an ecosystem • Invasive species – an exotic species which spreads quickly, dominating and vastly affecting an ecosystem. Example: Kudzu The Story Of Kudzu • Kudzu is a plant native to Japan; it was introduced to America in 1876 in Philadelphia as a forage crop. • With no natural predators, the plant spread quickly throughout the southeastern United States The Story of Kudzu • According to ScienceDaily , kudzu has been spreading in the southern U.S. at the rate of 150,000 acres annually. The Story of Kudzu • There is currently no fool-proof method for controlling the spread of kudzu. • As this vine spreads, it costs about $500 million annually in lost cropland and control measures. The Story of Kudzu • There is currently no fool-proof method for controlling the spread of kudzu. • As this vine spreads, it costs about $500 million annually in lost cropland and control measures. • The spread of the plant also causes huge changes in ecosystems as it chokes out native species. Another Example of Invasive Species pg 141-142 1) Describe how Zebra Mussels spread. When were they first introduced to North America? How long did it take for them to “colonize” the Great Lakes? 2) What is the problem with Zebra Mussels? 3) How do Zebra Mussels affect the population of zooplankton? 4) What organisms benefit from Zebra Mussels? 5) Explain why Zebra Mussels thrive in American waterways. .