STAAR biology questions grade 9

Kelp forests are critical ecosystems that provide habitats to many animals and also provide hunting grounds for mammals, including sea otters. In recent years scientists have documented an increase in shark attacks on sea otters in and around kelp forests.

Which consequence is most likely to occur in kelp forests as a result of increased predation of sea otters?

• Kelp forests will become more stable due to the decrease in otter predation pressure.

• Kelp forests will become more stable as sharks replace otters as the top predator in the food chain.

• Kelp forests will become less stable due to the increase in the size of the otters' prey populations.

• Kelp forests will become less stable as sharks will also eliminate the prey of the otters.

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Giant salvinia is a floating fern native to Brazil introduced to Texas as an aquarium plant and is now found in large bodies of water across the state. The invasive plant may be carried to new bodies of water by fishing and recreational boats. It grows quickly, covering large areas of the water's surface. When the plant dies and decays, the oxygen content in the water declines.

Which statement BEST describes how giant salvinia affects a Texas ecosystem?

• It promotes the growth of new types of plants.

• It increases the stability of the ecosystem.

• It provides an energy source for the ecosystem.

• It inhibits the growth of native plant species.

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Purple loosestrife is an invasive flowering plant species now found in North America. In an effort to control the purple loosestrife, biologists tested and released three beetle species to use as a biological control of the plant.

Which result is an unintended negative consequence of releasing these beetle species into the environment?

• There will be an increase in the available habitat for non-native plant species.

• There will be an increase in the population numbers of native beetle species in the habitat.

• There will be an increase in competition for food resources among all beetle species in the habitat.

• There will be an increase in pollination of native flowering plant species.

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East Texas has a wide variety of frog species that take advantage of different resources in the ecosystem, by eating different foods, choosing different ponds, and mating at different times of the year.
How does the biodiversity of frog species MOST LIKELY affect the stability of the ecosystem?

• By making the ecosystem more vulnerable to population losses

• By increasing the ecosystem's ability to stay healthy when conditions change

• By reducing the ability of individual organisms to adapt to changing conditions

• By making individual organisms less vulnerable to competition from invasive species

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The population of an invasive crab species, Callinectes sapidus, is rapidly increasing along coastal Europe. This aggressive, fast-growing omnivore reproduces quickly and is causing the extinction of many native species.

Which statement BEST describes the effect of a native species' extinction on local ecosystem biodiversity and stability?

• Extinction leads to decreases in biodiversity and decreases stability.

• Extinction leads to increases in biodiversity and decreases stability.

• Extinction leads to increases in biodiversity and increases in stability.

• Extinction leads to decreases in biodiversity and increases stability.

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Spores of the fungus Ustilago maydis land and grow on sweet corn. The fungus then infects the plant tissue, extracting nutrients from the plant's cells.

The relationship between sweet corn and Ustilago maydis can best be described as —

• competition

• commensalism

• predation

• parasitism

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TEKS.BIO.13.A

Ecological relationships occur between two species that live close to each other. Two examples of ecological relationships are described.

• Example 1: Bees gather nectar and pollen from flowering plants, providing food for the bees. As the bees move to different flowers, some of the pollen attached to the bees’ bodies is spread and released. If the pollen falls on the flower of a plant of the same species, it may fertilize the plant and produce seeds.

• Example 2: Orchids are flowering plants that grow on other plants. They typically grow in tall trees high in the canopy, where they can reach sunlight for photosynthesis. They get water and nutrients from rainwater runoff that carries organic material down the host plant’s branches. No water or nutrients are taken from the host plant.

What is the main difference between the ecological relationships described in the two examples? Include the scientific term used to define each of the relationships. Think about the question carefully. Then enter your answer in the box provided.

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The oak mistletoe is a green, leafy plant that grows on trees and has white berries. Mistletoe seeds are spread to other trees through the waste of birds that feed on the berries. The mistletoe seedlings grow into the tree to obtain water and nutrients.

Which answer choice correctly identifies a relationship between two of these organisms?

• The relationship between the tree and the mistletoe is commensalism.

• The relationship between the birds and the trees is predator-prey.

• The relationship between the birds and the trees is mutualism.

• The relationship between the tree and the mistletoe is parasitism.

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A student made a list of some ways that a species of fungi and a plant interact:

1. The fungus receives carbohydrates from the plant.

2. The fungus helps provide water to the plant’s roots.

3. The fungus provides minerals and nutrients to the plant.

Based on this information, what is MOST LIKELY the relationship between this species of fungi and the plant?

• Mutualism

• Commensalism

• Parasitism

• Predation

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A student lists facts about raccoons:

1. Coyotes and bobcats eat raccoons.

2. Raccoons will eat fruit and nuts after they have dropped onto the ground.

3. Raccoons eat a variety of foods, including fish, small rodents, and frogs.

4. Raccoons can use their fingers to open garbage cans to eat what is inside.

Which facts describe a predator-prey relationship?

• Facts 1 and 2

• Facts 1 and 3

• Facts 2 and 4

• Facts 3 and 4

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