Ecosystems: Biodiversity

Deforestation in the rainforest can lead to extinctions of populations of some organisms. Once an area is deforested, which is MOST likely to decrease and result in organisms' extinctions?

diversity of the resources in the habitat

What process occurs in an ecosystem after a lava flow has completely covered the surface of an area of land?

Primary succession

Water purification and climate regulation are examples of _______ that are beneficial to humans.

Ecosystem services

What are examples of natural ecosystem change?

A herd of grazing buffalo tramples on tree seedlings and digs up the ground, destroying the young trees. In the bare patches, new plants grow. A fire burns down a large area of forest. Only soil remains. The next season, small plants sprout. Over time, new trees reclaim this area. When a volcano erupts, the surrounding plants are destroyed and leave only bare lava. Pioneer species begin to grow on the lava. Over time, more and more different species reclaim this area. A beaver builds a dam and blocks a stream, forming a pond. Organisms that rely on fast moving water die out. Over time, populations of pond-loving species increase in the area.

Removing one tree from an ecosystem could impact the ecosystem by:

Destroying the habitat for part of a bird population that lives in the tree Changing the amount of light that reaches plants under the tree

When one population of organisms becomes extinct in an ecosystem, it makes the entire ecosystem less stable because:

All other populations will be changed in some way There is less biodiversity in the ecosystem

What is a TRUE statement about ecosystems?

All species in an ecosystem are connected to one another.

A change that affects one species of an ecosystem can affect:

All species in the ecosystem.

A fungal disease heavily infects one particular species in an ecosystem, greatly decreasing its population. What kind of ecosystem would experience the most instability following this disruption?

An ecosystem with a low amount of biodiversity

What is a FALSE statement about ecosystems?

Ecosystems rarely change in nature. Ecosystems only change in response to human disruptions.

What is the relationship between biodiversity loss and the ecosystem services provided by a given habitat?

As biodiversity decreases, ecosystem services decrease.

Which statement describes how biodiversity benefits ecosystem stability?

Biodiversity makes ecosystems better able to maintain its functions after a change.

In New Zealand, many populations in "shellfish-bed" ecosystems (where shellfish occupy 50% of the area) have declined due to changes in the habitat. How will this affect the biodiversity of shellfish-bed ecosystems?

Biodiversity will decrease as well as the number of available shellfish.

Deer are introduced into a grassland ecosystem and their population increases. If the deer population continues to grow, which is the MOST likely outcome for the ecosystem?

Biodiversity would decrease, and the ecosystem would become less sustainable.

Many living organisms provide food and raw materials for medicines, clothing, and other products. This is an example of the _______ value of biodiversity.

Economic

What is the final and most stable stage of change in an ecosystem?

Climax community

The population of algae increases in a lake, which blocks sunlight into the lake. As a result, less oxygen enters the lake's water. Which of the following should be expected as a result?

Fish populations in the lake decrease.

Humans use resources from ecosystems to get and/or make:

Food Clothing Medicine Jobs

The table shows the diversity of species in four forests. Tree SpeciesN M O P Forest 1 80% 8% 5% 7% Forest 2 15% 50% 15% 20% Forest 3 27% 23% 22% 28% Forest 4 12% 18% 46% 24% Which forest would be least likely to recover after the invasion of a new herbivore species that prefers Tree Species N?

Forest 1

A virus that kills deer is introduced to a forest. Many deer die, but some members of the deer population are naturally immune to the virus. Over time, the deer population recovers to its original levels. This is an example of how an ecosystem's stability is maintained by:

Genetic biodiversity

A forested area experiences heavy biodiversity losses due to commercial logging activity. How will this affect the well-being of humans living nearby?

Human well-being will be affected negatively due to the loss of ecosystem services.

An example of why protecting biodiversity in an ecosystem is important to humans is because

If the biodiversity decreases, it may decrease availability of important resources we use for food and medicine

A keystone species:

Influences the survival of many other species in the ecosystem

What type of plant is one of the first to colonize an area in an ecosystem that has been burned over leaving only barren ground?

Lichens

Having greater biodiversity in an ecosystem is beneficial to humans because

Losing biodiversity in an ecosystem may negatively impact a plant we rely on for food We may discover new plants that can be used for medicine Places with high biodiversity, such as rainforests and coral reefs, are popular tourism destinations

Which process occurs in an ecosystem after a fire has gone through a forest leaving only a few trees and shrubs?

Secondary succession

An ecosystem experiences a disruption as a single invasive species is introduced and rapidly begins outcompeting multiple native species. How is this going to affect the stability of the ecosystem?

The ecosystem will become less stable.

The main predators in a wetland ecosystem are wading birds. They eat frogs and fish, which in turn eat insects. If the wading birds leave the ecosystem:

The frog and fish populations will increase at first and then decrease as they run out of food

Scientists perform an experiment by removing a single species from a grassland with a high amount of biodiversity and a grassland with a low amount of diversity. Which community would experience the least amount of disruption from this change?

The grassland with a high amount of diversity.

What does biodiversity measure?

The number of different species in a given area.

Taxol is a medicine that is commonly used to treat cancer and was first discovered in a Pacific yew tree. If the biodiversity of the ecosystem that yew trees live in decreased, then...

The population of yew trees may decrease and thus taxol availability may decrease

What will happen during a drought in a wetland ecosystem? (Drought = loss of water)

The populations of all living things in the wetlands will be affected The size of the ecosystem will decrease

The economic value of biodiversity refers to

The ways that humans benefit from biodiversity

An ecologist makes several measurements of a wetland ecosystem. Which one would be considered a measurement of its biodiversity?

The wetland is a habitat for at least 38 species of birds.

What effect does biodiversity have on the overall stability of an ecosystem following a disturbance?

There is a direct relationship between biodiversity and ecosystem stability.

What is an example of primary ecological succession?

lichen growth on rocks

This food chain shows some predator-prey relationships in a wetland ecosystem. Plants → Insects → Small Fish → Frogs → Wading Birds Based on the food chain, if the population of frogs were to increase, which populations of organisms would immediately begin to decrease?

small fish