Biomes: Terrestrial Ecosystems — Reading Comprehension

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Grades

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MS-LS2-1

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This NGSS-aligned science reading passage for grades 6-8 provides a comprehensive survey of Earth’s major terrestrial biomes, including tropical rainforests, temperate and boreal forests, grasslands, deserts, and tundra. The passage introduces students to the mechanisms that define each biome, such as climate and dominant vegetation, and explains how environmental factors drive the adaptation of characteristic organisms. Through examples and scientific reasoning, students discover cause-and-effect relationships within biomes and the underlying principles that connect them as part of the biosphere. Activities include vocabulary, comprehension quiz, writing analysis, and graphic organizers to deepen understanding. Audio integration supports diverse learners. This resource is ideal for supporting instruction on ecosystems, biodiversity, and environmental science, and is aligned with NGSS standard MS-LS2-1.

CONTENT PREVIEW

biome-1 — Illustration showing Earth's major biomes

Biomes are large regions on Earth defined by their climate, vegetation, and the unique communities of organisms they support. Scientists study biomes to understand the complex relationships between living things and their environments. The distribution of biomes across the planet is determined by patterns of temperature, precipitation, and sunlight. Each terrestrial biome serves as a system where energy flows and matter cycles, shaping the diversity of life found there.

Climate and Vegetation: The Foundations of Biomes
Climate is the main force that shapes terrestrial biomes. For example, tropical rainforests are found near the equator, where temperatures average above 25°C (77°F) year-round, and annual rainfall can exceed 200 centimeters (79 inches). This warm, wet climate supports dense forests with the highest biodiversity on Earth. Temperate forests have moderate climates and distinct seasons; their trees are often deciduous (shedding leaves) or coniferous (evergreen). The taiga, or boreal forest, exists in colder regions with long winters and short summers. Its coniferous trees are adapted to snow and freezing temperatures.

Adaptations and Organism Interactions
Plants and animals in each biome have unique adaptations that help them survive. In grasslands, such as prairies and savannas, moderate rainfall favors grasses over trees. Large herbivores like bison and antelope graze on tough grasses, while predators like lions and wolves depend on these herbivores for food. Deserts receive less than 25 centimeters (10 inches) of rain annually, leading to extreme temperature changes between day and night. Cacti and succulents store water, and many desert animals are nocturnal to avoid daytime heat. In the tundra, permafrost keeps the soil frozen most of the year, limiting plant growth to mosses and low shrubs. Animals like caribou and arctic foxes have thick fur and fat layers for insulation.

Biomes as Interconnected Systems
Biomes interact with each other and influence the global climate. For instance, forests absorb carbon dioxide and release oxygen through photosynthesis, helping regulate Earth's atmosphere. Grasslands can support large migrations of animals, which spread seeds and nutrients. Destruction of one biome through deforestation or climate change can disrupt food webs and affect other biomes. Scientists use satellite data, field studies, and climate models to monitor and predict changes in biome distribution and health.

Understanding biomes helps us recognize the importance of biodiversity and the need to protect ecosystems. Each biome plays a vital role in maintaining Earth's balance and supporting life.

Interesting Fact:
The Amazon rainforest, the largest tropical rainforest, contains about 10% of all known species on Earth!

Which two environmental factors are most important in determining a terrestrial biome?

Climate and vegetationSoil and altitudeOcean currents and wind speedAnimal population and rainfall

What is one main difference between temperate forests and taiga forests?

Taiga forests are warmer and wetter.Temperate forests have more coniferous trees.Taiga forests are colder with more evergreen trees.Temperate forests have no animals.

Which biome is known for having the highest biodiversity?

TundraTropical rainforestGrasslandDesert

What does the word 'adaptation' mean as used in the passage?

A type of weather patternA feature or behavior that helps living things surviveA kind of ecosystemA food chain process

What does 'permafrost' refer to in the context of the tundra biome?

Frozen ground all yearMelted ice in summerA type of grassTall trees

Why are many desert animals active at night?

To avoid daytime heatBecause there is more foodBecause it rains at nightTo find water easily

How can the destruction of one biome affect other biomes?

It only changes the local weather.It disrupts food webs and impacts other ecosystems.It causes more rainfall everywhere.It has no effect on other biomes.

If a forest biome is cut down, what is one likely result?

Increase in oxygen productionLoss of biodiversity and climate changesGrowth of new desertsMore animal migrations

True or False: Grasslands support large migrations of animals that help spread seeds and nutrients.

TrueFalse

True or False: The Amazon rainforest contains about 1% of all known species on Earth.

TrueFalse