Relationships in Ecosystems

Two plant species that grow in the same area are shown.

Which statement best explains a difference between Plant 1 and Plant 2?

• Plant 1 obtains more water from the soil because of its root surface area and root depth

• Plant 1 obtains more sunlight because of its root surface area and root depth

• Plant 2 obtains more water from the soil because of its root surface area and root depth

• Plant 2 obtains more sunlight because of its root surface area and root depth

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112.20.b.11.A

Sea anemones and clown fish live together in the ocean. Which statement best describes one way sea anemones depend on clown fish for an abiotic factor in an ecosystem?

• Clown fish protect sea anemones from predatory fish

• Clown fish decrease competition among sea anemones

• Clown fish consume the remains of organisms paralyzed by sea anemones

• Clown fish move water near sea anemones when dissolved oxygen levels are low

Tags

112.20.b.11.A

Immediately after a forest fire, the primary consumers in the area will compete most for which biotic factor?

• Food

• Space

• Oxygen

• Sunlight

Tags

112.20.b.11.A

Three different species of plants that live in the desert are shown.

Species Z can successfully share the same environment with the other plants shown because species Z absorbs water -

• found deep underground, and species X absorbs water near the soil surface

• found deep underground, and species X absorbs water found deep underground

• near the soil surface, and species Y absorbs water near the soil surface

• near the soil surface, and species Y absorbs water found deep underground

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112.20.b.11.A

Plants that live on the floors of densely populated forests must compete for sunlight. Which type of leaves are most likely found on plants that are best suited to living on the floor of a dense forest?

• Leaves that are needle shaped

• Leaves that are smallest

• Leaves that store the greatest amount of water

• Leaves with the greatest amount of surface area

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112.20.b.11.A

Wild hogs introduced to Texas from Europe became feal after the hogs escaped from the ranches where they lived. Feral hogs are omnivores that feed on native plants, crops, and small animals. Feral hogs can damage an ecosystem by rooting through the soil the look for food and trampling small plants.

Which types of native organisms do feral hogs most likely compete with for food sources?

• Carnivores and producers

• Herbivores and carnivores

• Producers and decomposers

• Decomposers and herbivores

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112.20.b.11.A

Giant salvinia is an aquatic plant that floats on water and reproduces rapidly. When these plants die, decomposition by bacteria affects oxygen levels in the water. As more plants die, less oxygen is available in the water.

Which statement is the best prediction about the immediate future of the pond?

• The depth of the water in the pond will increase

• Fish populations in the pond will begin to decrease

• The amount of bacteria in the pond will suddenly decrease

• The number of different types of plants around the pond will increase

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112.20.b.11.A

Plants grow in many different shapes and sizes. Much of their shape depends on an internal structure that is composed of carbon-containing molecules such as cellulose and lignin. Plants that have a strong internal structure can grow larger than other plants because their structure can support their size.

Plants obtain the majority of the carbon necessary for building these structural molecules from ​ (a)   .

• air
• microorganisms
• soil
• water

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112.20.b.11.A

Whitetip reef sharks spend most of the day lying on the ocean floor. While remaining still, these sharks pump water across their gills.

The movement of water across their gills is necessary for ​ (a)   .

• obtaining oxygen
• staying cool
• accessing food
• avoiding predators

Tags

112.20.b.11.A

A scientist added bacteria and a nutrient medium that could support the growth of the bacteria to a sterilized petri dish. No other materials were added. The graph models growth of the bacteria over time.

Which of these most likely explains why the bacterial population stopped growing?

• The bacteria competed for nutrients and died after all the nutrients were consumed

• The bacteria did not reproduce in the system, and eventually each individual died at the end of its life cycle

• The bacteria mutated from photosynthetic to carnivorous organisms and consumed one another until all the individuals were dead

• The bacteria became diseased and were unable to survive in the closed system

Tags

112.20.b.11.A