Biomes

The tropical rainforest biome covers equatorial regions and supports extraordinary biodiversity. Plants and animals have

Ecosystems under stress

Biomes

The savanna is a tropical grassland biome with a long dry season and a short wet season. Plants and animals have develop

Ecosystems under stress

Biomes

A biome is a large-scale global ecosystem — a distinct community of plants and animals shaped primarily by climate — and

Ecosystems under stress

Case studies

You need a real regional example where ecosystems are changing. You must explain why they are changing and how that affe

Ecosystems under stress

Case studies

You need a detailed case study of one small-scale ecosystem. You must know what it is like, how humans have damaged it,

Ecosystems under stress

Case studies

This subtopic asks you to apply everything you have learned about ecosystems — the interconnected communities of living

Ecosystems under stress

Ecosystems and processes

An ecosystem is a community of living things interacting with their physical environment. Energy passes from plants to a

Ecosystems under stress

Ecosystems and processes

An ecosystem works like a system. Energy and materials enter it, move between living and non-living parts, get stored, a

Ecosystems under stress

Ecosystems and processes

Biomass is the total mass of living material in an ecosystem. Net primary production measures how much new plant materia

Ecosystems under stress

Ecosystems and processes

Succession describes how an ecosystem changes through predictable stages over time. Left alone, it builds toward a stabl

Ecosystems under stress

Ecosystems and processes

Ecosystems continuously reuse the same minerals — such as nitrogen and phosphorus — by cycling them between plants, anim

Ecosystems under stress

Ecosystems and processes

Terrestrial ecosystems — land-based living systems — exist because climate, vegetation, soil and landform shape each oth

Ecosystems under stress

Ecosystems and processes

When one part of an ecosystem changes — such as temperature, rainfall, or a species population — the rest of the system

Ecosystems under stress

Ecosystems and processes

Ecosystems change when climate shifts or humans disturb them. Rising temperatures, deforestation, and overgrazing can al

Ecosystems under stress

Ecosystems and processes

Living systems — from a patch of woodland to a tropical rainforest — run on a set of underlying processes that govern ho

Ecosystems under stress

Ecosystems and sustainability

Biodiversity means the variety of living species in an area. Scientists measure it at local scales, like a single woodla

Ecosystems under stress

Ecosystems and sustainability

Human activities are wiping out species faster than nature can replace them. This loss of variety in living things — cal

Ecosystems under stress

Ecosystems and sustainability

Ecosystems supply humans with food, clean water, and climate regulation. Growing populations and expanding economies put

Ecosystems under stress

Ecosystems and sustainability

Human populations both shape ecosystems and depend on them. Growing populations and economic development can disrupt nat

Ecosystems under stress

Ecosystems and sustainability

Biodiversity — the variety of species and habitats within an ecosystem — is declining at both local and global scales, d

Ecosystems under stress

Ecosystems in the British Isles over time

Ecosystems change gradually over time as one community replaces another. This process, called succession, ends at a clim

Ecosystems under stress

Ecosystems in the British Isles over time

Temperate deciduous woodland is the natural end-point of ecosystem development in the British Isles. Left undisturbed, t

Ecosystems under stress

Ecosystems in the British Isles over time

Human activity can permanently stop succession before it reaches its natural endpoint. The result is a plagioclimax — a

Ecosystems under stress

Ecosystems in the British Isles over time

Left undisturbed, ecosystems change gradually over time through a process called succession — where simple pioneer commu

Ecosystems under stress

Local ecosystems

Local ecosystems are small-scale communities of plants and animals shaped by their local environment. Heathland, ponds,

Ecosystems under stress

Local ecosystems

Plants and animals develop special features to survive the specific climate, soil type, and water availability of their

Ecosystems under stress

Local ecosystems

Human activities — farming, urban development, and introducing non-native species — can alter or completely redirect how

Ecosystems under stress

Local ecosystems

Human activities damage local ecosystems by reducing biodiversity — the variety of species present. Conservation strateg

Ecosystems under stress

Local ecosystems

Distinctive local ecosystems — such as heathland, sand dune systems, ponds, and managed parkland — show how climate, soi

Ecosystems under stress

Marine ecosystems

Coral reefs are highly biodiverse underwater ecosystems built by tiny animals called coral polyps. They grow only in war

Ecosystems under stress

Marine ecosystems

Coral reefs can only survive within very specific natural conditions. Changes in water temperature, acidity, saltiness,

Ecosystems under stress

Marine ecosystems

Human activities damage coral reefs in several distinct ways. Pollution, coastal building, tourism, and fishing all degr

Ecosystems under stress

Marine ecosystems

Scientists predict that coral reefs face severe decline this century. Rising sea temperatures and ocean acidification th

Ecosystems under stress

Marine ecosystems

Coral reefs are among the most biodiverse ecosystems on Earth — meaning they support an exceptionally wide variety of sp

Ecosystems under stress