Question

Directions: Answer the following questions in your own words using complete sentences. Do not copy and paste from the lesson or the internet.

1. What is the definition of a community in environmental science? Give an example of a community. What does a species first have to do in order to become a member of a community?

2. What is a habitat? Under what conditions can two or more species inhabit a habitat? Be specific and give examples.

3. Under what conditions is species diversity the greatest?

4. Explain the concepts of protocooperation, mutualism, commensalism, parasitism? Give an example of each. What is tolerance? Give an example. How do interactions among species influence what exists in a community? Give some examples of positive and negative interactions. How does predation affect a community? What happens when a keystone predator is removed from a community?

5. What causes community changes? Compare and contrast primary succession and secondary succession. Be specific and give examples.

Answer 1

A community in environmental science is a group of different species living together and interacting in a specific area. For example, a coral reef ecosystem is a community where corals, fish, algae, and invertebrates coexist. To become a member of a community, a species needs to find a suitable habitat and establish interactions with other species.

A habitat is the specific physical environment where organisms live. It includes both living and non-living factors that affect survival and reproduction. Two or more species can inhabit a habitat when they can coexist and share resources without significant competition. For instance, a forest habitat accommodates various trees, understory plants, birds, mammals, and insects, each occupying different niches.

Species diversity is greatest under conditions of high ecological complexity, such as diverse habitats, moderate environmental disturbance, and a wide range of resources. Biodiversity is higher in tropical rainforests, coral reefs, and diverse ecosystems that provide various niches for species to thrive.

Protocooperation is a mutually beneficial interaction between different species without full dependency. An example is oxpecker birds feeding on ticks from zebras, benefiting from food while the mammals get parasite removal. Mutualism is a symbiotic relationship where both species benefit, like flowering plants providing nectar for bees while bees aid in pollination. Commensalism benefits one species without affecting the other, such as orchids growing on tree branches. Parasitism benefits the parasite at the host's expense, like ticks feeding on mammalian blood. Tolerance is the ability of species to withstand challenging conditions, such as plants tolerating extreme temperatures.

Interactions among species influence community composition, structure, and dynamics. Positive interactions like mutualism and protocooperation enhance diversity, while negative interactions like competition and predation limit certain species. Predation affects population dynamics and distribution of prey, which cascades through the community. The removal of a keystone predator disrupts the balance, leading to increased prey abundance and potential negative impacts on other species.

Community changes can result from natural disturbances, human activities, climate change, and evolutionary processes. Primary succession occurs in lifeless areas like bare rock, starting with pioneer species such as lichens. They modify the environment, enabling the establishment of other species. Secondary succession happens in disturbed areas with remnants of the previous community, beginning with fast-growing plants and eventually restoring a diverse community. Examples include the formation of a new island through volcanic activity (primary succession) and forest regeneration after a fire (secondary succession).

Answer 2

1. In environmental science, a community refers to a group of interacting species that live together in a particular habitat. An example of a community is a coral reef ecosystem, which includes a variety of species such as fish, algae, and invertebrates. In order to become a member of a community, a species must be able to survive and reproduce in the habitat and interact with other species.

2. A habitat is the physical environment where a particular species lives and obtains its resources, such as food, water, and shelter. Two or more species can inhabit a habitat if they are able to coexist and share resources without competition or conflict. For example, in a freshwater pond, various species of fish, frogs, and insects can coexist if they occupy different niches within the habitat.

3. Species diversity is greatest under conditions of high productivity, stable environmental conditions, and low levels of disturbance. For example, a tropical rainforest with high levels of rainfall and temperature stability will typically have greater species diversity than a desert with harsh and unpredictable environmental conditions.

4. Protocooperation refers to a mutually beneficial relationship between two species that work together, but not as closely as in mutualism. An example is the relationship between bees and flowers, where bees collect nectar from flowers for food and in the process, help pollinate the flowers. Mutualism is a relationship where both species benefit from each other. An example is the relationship between bees and flowers, where bees collect nectar for food, and in the process, transfer pollen from one flower to another, aiding in reproduction. Commensalism refers to a relationship where one species benefits while the other is neither helped nor harmed. An example is the relationship between barnacles and whales, where barnacles attach themselves to the whale's skin and gain protection and access to food, while the whale is not affected. Parasitism refers to a relationship where one species benefits while the other is harmed. An example is the relationship between ticks and deer, where the tick feeds on the deer's blood, causing harm and potentially spreading disease. Tolerance refers to a species' ability to survive and reproduce in the presence of other species. An example is the ability of some plant species to tolerate shade from other plants. Interactions among species influence what exists in a community by affecting population sizes, distribution, and resource availability. Positive interactions, such as mutualism, can promote coexistence and increase species diversity, while negative interactions, such as competition or predation, can limit population sizes and reduce species diversity.

5. Community changes can be caused by both biotic and abiotic factors, such as climate change, natural disasters, and human activities. Primary succession occurs in areas where no soil exists, such as on newly formed volcanic islands or after a glacier retreats. In this process, pioneer species such as lichens and mosses begin to colonize the area, gradually building up soil and creating conditions for other plant species to grow. Secondary succession occurs in areas where soil already exists, such as after a forest fire or clear-cutting. In this process, plant and animal species gradually recolonize the area, with some species growing more quickly than others depending on their adaptations and the availability of resources. An example of primary succession is the colonization of the volcanic island of Surtsey by pioneer species, while an example of secondary succession is the regrowth of a forest after a fire.

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