Unit 11 Biomes

Terrestrial

Land biomes

Aquatic

Water biomes

Deciduous Forest

A biome dominated by trees that shed their broad leaves annually, typically in the autumn, to conserve water and energy during cold or dry seasons. These forests are characterized by four distinct seasons (in temperate regions), moderate climate conditions, and high biodiversity.

Grasslands

A large, terrestrial ecosystem dominated by grasses, sedges, and other herbaceous plants rather than large shrubs or trees. These regions typically feature flat or rolling terrain, moderate rainfall that prevents them from becoming deserts, and frequent fires or grazing that keep woody vegetation from taking over

Tiaga

Also known as the boreal forest or snow forest, is the world's largest terrestrial biome, a cold subarctic region dominated by coniferous evergreen trees like spruce, fir, and pine. It forms a vast, unbroken belt across the Northern Hemisphere—covering parts of Canada, Alaska, Scandinavia, and Russia (Siberia)—located between the tundra to the north and temperate forests to the south

Tundra

A cold, treeless biome characterized by extremely low temperatures, little precipitation, poor nutrients, and short growing seasons. It is defined by the presence of permafrost—a permanently frozen sublayer of soil—and is often considered a "treeless plain" or "cold desert."

Savanna

A mixed woodland-grassland ecosystem (or grassy woodland) characterized by trees sufficiently spaced to allow an unbroken herbaceous layer of grasses to grow, featuring a warm climate with distinct wet and dry seasons. Commonly known as tropical grasslands, they often feature scattered trees and support large, migratory herbivores

Desert

A dry, arid ecosystem receiving less than 25-50 cm (10-20 inches) of precipitation annually, characterized by low biodiversity, sparse vegetation, and extreme daily temperature fluctuations. These environments can be hot (e.g., Sahara) or cold (e.g., Gobi), featuring specialized plant life like cacti and drought-tolerant animals

Freshwater

a large community of plants and animals adapted to water with a low salt concentration, typically less than. Covering less than of Earth's surface, these essential aquatic ecosystems—including lakes, rivers, ponds, and wetlands—house over known species and provide crucial drinking water.

Permafrost

When ground—soil, rock, or sediment—that remains frozen at or below 0°C (F) for at least two consecutive years, often persisting for thousands of years.

Climate

The long-term average of weather patterns in a specific region, typically calculated over 30 years or more, including temperature, precipitation, humidity, and wind

Estruary

a partially enclosed coastal body of water where freshwater from rivers and streams mixes with salt water from the ocean. These dynamic, nutrient-rich "transition zones" (between land and sea) are often called bays, sounds, or marshes. They are characterized by tidal action and brackish water

Tributary

A freshwater stream or river that flows into a larger stream, river, or lake, rather than directly into the ocean

Wetland

A land area saturated or covered with water—either permanently or seasonally—supporting specialized plants (hydrophytes) and hydric soils

Marine

The world's largest aquatic ecosystem, covering approximately 70% of Earth, is characterized by high-salinity saltwater (30-38 ppt). It includes oceans, coral reefs, and estuaries, spanning from sunlit surface waters to deep, dark abyssal zones.

Deforestation

The purposeful and permanent clearing of forested land, typically driven by human activities like agriculture, logging, and urban development. It involves removing trees on a large scale, transforming forest ecosystems into non-forest land uses such as cattle ranches, farms, or infrastructure, causing significant biodiversity loss and climate disruption

Desertification

The degradation of dryland ecosystems, where fertile land becomes arid or semi-arid desert due to human activities (deforestation, overgrazing) and climate change (drought)

Overgrazing

The detrimental environmental condition occurring when plants are exposed to intensive grazing for extended periods, or without sufficient recovery time, exceeding the land's carrying capacity. It causes reduced plant yield, soil erosion, and biodiversity loss.

Logging

Extraction of trees for timber, fuel, or land clearing causes significant environmental degradation, biodiversity loss, and habitat fragmentation. It involves removing trees for human use, which disrupts ecosystems and releases stored carbon, contributing to climate change

Overdevelopment

The unsustainable expansion of human infrastructure, industries, and consumption beyond the capacity of Earth's ecosystems to regenerate, resulting in severe degradation of the environment and biodiversity loss.

Climate Change

long-term shifts in temperatures and weather patterns caused by human activities since the 1800s, primarily the burning of fossil fuels (coal, oil, gas) [3]. This adds greenhouse gases like carbon dioxide and methane to the atmosphere, trapping heat and raising global temperatures

Oil Drilling

The physical, chemical, and biological disruptions caused by the exploration, extraction, and transport of petroleum result in habitat destruction, pollution, and biodiversity loss. These activities disturb terrestrial and marine environments through noise pollution, vegetation clearing, toxic leaks, and spills, often leading to long-term ecological damage.

Oil Spills

The release of liquid petroleum hydrocarbons (crude oil, gasoline, or diesel) into the environment, particularly marine ecosystems, due to human activity, accidents, or negligence. These spills can occur from tankers, offshore platforms, or pipelines, forming harmful slicks on water or contaminating land, requiring cleanup and causing long-term environmental damage.

Pollution

The introduction of harmful materials—contaminants or waste—into the natural environment (air, water, or soil) makes it unsuitable or unsafe for use. These substances, known as pollutants, can be chemical or energy-based, such as noise, heat, or light, damaging ecosystems and human health.