Ch 1.9 Keystone Species

Ch 1 9 Keystone Species Ch 1 9 Keystone Species What is a Keystone? ● A keystone is the wedge shaped stone in the middle of a arch or vault ● It is the final piece placed during construction and locks[.]

Ch 1.9 Keystone Species What is a Keystone? ● ● ● A keystone is the wedge-shaped stone in the middle of a arch or vault It is the final piece placed during construction and locks all the stones into position, allowing the arch or vault to bear weight Draw this model: Keyston in Ecosystems ● In any type of ecosystem, a keystone species is an organism that helps hold the system together ● A keystone species helps define an entire ecosystem ○ If the species were to disappear from the ecosystem, no other species would be able to fill its ecological niche Importance of Keystone Species ● ● ● Without its keystone species, ecosystems would look very different Some ecosystems might not be able to adapt to environmental changes if their keystone species disappeared That could spell the end of the ecosystem, or it could allow an invasive species to take over and dramatically shift the ecosystem in a new direction Let’s remember the case of twin islands: Amchitka & Shemya Three types of keystone species: Predators, Ecosystem Engineers & Mutualist Predators:Predators help control the populations of prey species, which in turn affects the quantity of plants and animals further along the food web ○ Sharks, for example, often prey upon old or sick fish, leaving healthier animals to flourish ○ Sharks are able to keep smaller animals from overgrazing and wiping out the grass ○ When tiger sharks patrolled the grass beds, the sea turtles were forced to graze across a much wider region Ecosystem Engineers Ecosystem engineer: an organism that creates, changes, or destroys a habitat ● For example of a beaver River ecosystems rely on beavers to take down old or dead trees along riverbanks to use for their dams This allows new, healthier trees to grow in abundance The dams divert water in rivers, creating wetlands that allow a variety of animals and plants to thrive Mutualist Mutualists: When two or more species in an ecosystem interact for each other’s benefit, they are called mutualists ● Bees are a primary example of this As bees take the nectar from flowers, they collect pollen and spread it from one flower to the next, enhancing the odds of fertilization and greater flower growth  ... niche Importance of Keystone Species ● ● ● Without its keystone species, ecosystems would look very different Some ecosystems might not be able to adapt to environmental changes if their keystone. .. a Keystone? ● ● ● A keystone is the wedge-shaped stone in the middle of a arch or vault It is the final piece placed during construction and locks all the stones into position, allowing the arch... twin islands: Amchitka & Shemya Three types of keystone species: Predators, Ecosystem Engineers & Mutualist Predators:Predators help control the populations of prey species, which in turn affects