2.2 Study Guide [ 2.2 Sequence Assessment 1/21 and 1/22] Ecosystems and Ecological Relationships Invasive Species ● An invasive species is a plant, animal, or organism that is not native to a specific area and causes harm to the environment or human health. Why are they harmful? Invasive species often outcompete native species for food, water, and space. They can spread quickly because they lack natural predators in the new environment. What is their impact on the ecosystem? Invasive species can reduce biodiversity by pushing native species to extinction or by changing the habitat in which native species live. Biodiversity and Its Importance to Ecosystems Biodiversity refers to the variety of life in a specific area, including different species of plants, animals, and microorganisms, and the ecosystems they form. ● Stability: Biodiversity makes ecosystems more resilient to changes such as climate change, diseases, and natural disasters. ● Food chains and webs: A greater variety of species means more sources of food for different animals, helping maintain a balanced food web. For example, a forest with many species of plants and animals can recover from a drought more easily than a forest with fewer species. Predator-Prey Relationships In a predator-prey relationship, one organism (the predator) hunts and eats another organism (the prey). The predator benefits by getting food, while the prey loses its life.The population sizes of predators and prey are often linked. If there are more prey, the predator population may grow, but if too many predators eat the prey, the predator population will decrease. This relationship can be shown in the graph below. ● For example: Lions hunt zebras for food. When there are many zebras, lions have more food and their population can grow. However, if too many lions eat the zebras, the zebra population can decrease. Predator-prey relationships help keep animal populations balanced, preventing one species from becoming too numerous and harming the environment. Ecological Relationships There are several types of relationships between organisms in an ecosystem. These include commensalism, parasitism, and mutualism. Commensalism In commensalism, one organism benefits from the relationship while the other is neither helped nor harmed. An example would be Barnacles and Whales. Barnacles attach to the skin of whales. The barnacles get access to nutrient-rich water while the whale swims, but the whale is not affected by their presence. Parasitism In parasitism, one organism (the parasite) benefits at the expense of the other organism (the host), which is harmed. For example, fleas live on dogs and feed on their blood. The fleas benefit, but the dog may suffer from itching, infections, or even anemia. Another example are tapeworms and humans. Tapeworms live in the intestines of humans and absorb nutrients, leaving the human host malnourished. Mutualism In mutualism, both organisms benefit from the relationship. An example would be bees and flowers: Bees collect nectar from flowers to make honey, while helping the flowers by transferring pollen, which helps them reproduce.