Ecosystems — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
The tundra biome receives the most rainfall of any biome on Earth.
Corrected: The tropical rainforest biome receives the most rainfall of any biome on Earth.
The tundra is one of the driest biomes on Earth, receiving very little precipitation. Tropical rainforests get the most rainfall, often over 80 inches per year.
2. Fix the sentence:
Cacti grow thick leaves to store as much sunlight as possible in the desert.
Corrected: Cacti grow thick stems to store as much water as possible in the desert.
Cacti actually have thick stems, not leaves, that store water for dry periods. Their spines are modified leaves that reduce water loss and protect against animals.
3. Fix the sentence:
A grassland biome is mostly covered by tall trees and gets very little sunlight.
Corrected: A grassland biome is mostly covered by grasses and gets plenty of sunlight.
Grasslands are wide-open areas dominated by grasses with very few trees, allowing plenty of sunlight to reach the ground and support grazing animals.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A biome is a large region with a specific climate, plants, and animals.
A biome is a large geographic area classified by its climate, typical plants, and animals, such as deserts, grasslands, or tropical rainforests.
2. The two main factors that determine a biome are temperature and precipitation.
Temperature and precipitation together control which plants can grow in an area, which in turn determines the animals that live there and the type of biome.
3. Animals in cold biomes often have thick fur or blubber to stay warm.
Thick fur traps a layer of warm air close to the body, insulating animals like arctic foxes and polar bears from freezing cold temperatures.
4. A deciduous forest biome has trees that lose their leaves every autumn.
Deciduous trees shed their leaves in autumn to conserve water and energy during the cold winter months, then grow new leaves in spring.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Why do tropical rainforests have more biodiversity than deserts?
Sample answer: Tropical rainforests have more biodiversity because they receive abundant rainfall and warmth year-round. These conditions support many different plants, which in turn provide food and shelter for a huge variety of animals.
A good answer includes: Tropical rainforests have more biodiversity because they receive abundant rainfall and warmth year-round. These conditions support many different plants, which in turn provide food and shelter for a huge variety of animals.
2. How does the amount of precipitation affect the types of plants that grow in a biome?
Sample answer: Areas with high precipitation can support large trees and dense vegetation, while areas with very little precipitation only support drought-resistant plants like cacti and short grasses. The amount of water available determines which plants can survive.
A good answer includes: Areas with high precipitation can support large trees and dense vegetation, while areas with very little precipitation only support drought-resistant plants like cacti and short grasses. The amount of water available determines which plants can survive.