Glossary of Biodiversity

Understanding biodiversity and species diversity requires knowing some essential scientific terms. These words describe how life on Earth is organized, measured, and conserved. Below is an expanded glossary of key terms, explained clearly and completely.

Abiotic Factors

Non-living physical and chemical components of an environment — such as sunlight, temperature, water, and minerals — that influence where and how organisms live.

Adaptation

A structural, behavioral, or physiological characteristic that improves an organism’s ability to survive and reproduce in its environment. For instance, cactus spines prevent water loss and deter herbivores in deserts.

Alien Species (Exotic or Introduced Species)

Species that occur outside their native range due to human activities. Some become invasive, competing with native species and disrupting ecosystems.

Allele

A version or form of a gene responsible for specific traits, such as flower color or disease resistance. Genetic variation among alleles contributes to a species’ adaptability.

Biodiversity (Biological Diversity)

The total variety of life on Earth — including plants, animals, fungi, and microorganisms — as well as the ecosystems they form. Biodiversity includes three main levels:

Genetic diversity (within species)
Species diversity (between species)
Ecosystem diversity (across ecosystems).

Biome

A large geographic region characterized by specific climate conditions and dominant plant and animal life, such as rainforests, deserts, tundras, or grasslands.

Biosphere

The global sum of all ecosystems — essentially all living organisms and the environments that support them on Earth.

Biogeography

The scientific study of the geographic distribution of species and ecosystems over space and time.

Biotic Factors

Living components of an ecosystem — plants, animals, fungi, bacteria, and their interactions — that influence ecosystem health and balance.

Carrying Capacity

The maximum number of individuals of a species that an environment can sustainably support based on available resources.

Climate Change

Long-term alteration of temperature and weather patterns, mainly due to human activities like burning fossil fuels and deforestation. It affects species survival, migration, and ecosystem balance.

Community (Ecological Community)

A group of populations of different species living and interacting in a shared environment.

Competition

An interaction where organisms vie for the same limited resources (such as food, light, or territory), influencing population dynamics.

Conservation

The protection, preservation, and sustainable management of biodiversity and natural resources. Conservation aims to prevent species extinction and maintain ecological stability.

Conservation Biology

A field of science focused on understanding and mitigating biodiversity loss through research, habitat protection, and restoration efforts.

Coral Reef

A highly diverse marine ecosystem formed by colonies of coral polyps. Coral reefs are biodiversity hotspots supporting thousands of marine species.

Deforestation

The large-scale removal of forest cover for agriculture, urbanization, or industry, often leading to habitat destruction and species extinction.

Decomposer

Organisms such as fungi, bacteria, and certain insects that break down dead material, recycling nutrients into ecosystems.

Desertification

The degradation of fertile land into desert due to factors like drought, deforestation, and overgrazing.

DNA (Deoxyribonucleic Acid)

The molecule that contains genetic information in living organisms, determining inherited traits and biological functions.

Diversity Hotspot (Biodiversity Hotspot)

A region rich in endemic species and under serious threat from human activity. Examples include Madagascar, the Western Ghats, and the Amazon Basin.

Ecosystem

A community of living organisms interacting with one another and with their physical environment. Examples include forests, lakes, coral reefs, and tundras.

Ecosystem Diversity

The variety of habitats, biological communities, and ecological processes within a given region or across the planet.

Ecosystem Services

The benefits humans gain from ecosystems, such as pollination, clean water, oxygen, food, and climate regulation.

Ecological Balance

A state of dynamic stability within ecosystems, where species and environmental factors interact harmoniously. Disturbances like pollution or invasive species can upset this balance.

Ecological Niche

The role a species plays in its environment — including what it eats, how it interacts, and where it lives.

Endangered Species

Species at a high risk of extinction in the near future due to habitat loss, hunting, pollution, or climate change.

Endemic Species

Species that occur naturally in only one geographic area, often isolated, such as the lemurs of Madagascar.

Environment

The external surroundings — biotic and abiotic — that affect an organism’s growth, survival, and reproduction.

Evolution

The process by which species change over generations through genetic variation and natural selection.

Ex-Situ Conservation

Protecting species outside their natural habitats, for example, in zoos, aquariums, botanical gardens, and gene banks.

Extinction

The complete disappearance of a species from Earth. It can be natural or accelerated by human activities.

Fauna

All animal life of a particular region or geological period.

Flora

All plant species of a particular region or period.

Food Chain

A sequence showing how energy passes from one organism to another, e.g., grass → rabbit → fox.

Food Web

A complex network of interconnected food chains illustrating how energy and nutrients flow within an ecosystem.

Fragmentation (Habitat Fragmentation)

The breaking of large, continuous habitats into smaller patches, isolating species and reducing biodiversity.

Gene

A segment of DNA that carries the instructions for making a specific protein or trait.

Genetic Diversity

The variation in genes within a species, allowing populations to adapt to changing environments and resist diseases.

Gene Flow

The transfer of genetic material between populations, maintaining diversity and reducing inbreeding.

Geographical Isolation

Physical separation of populations by barriers (like rivers or mountains), often leading to the formation of new species.

Genome

The complete set of genetic material in an organism.

Habitat

The natural environment where a species lives, grows, and reproduces. Examples include coral reefs, rainforests, and grasslands.

Habitat Loss

The destruction or degradation of habitats through deforestation, pollution, or urbanization — a major cause of species extinction.

Hybridization

The interbreeding between individuals of different species or populations, sometimes producing hybrid offspring.

Indicator Species

Species whose presence or absence signals the health of an ecosystem (e.g., frogs as indicators of clean water).

In-Situ Conservation

Protecting species in their natural habitats, such as through national parks, biosphere reserves, or wildlife sanctuaries.

Invasive Species

Non-native species that spread rapidly and cause harm to native species and ecosystems, such as zebra mussels or water hyacinth.

IUCN Red List

A global inventory maintained by the International Union for Conservation of Nature that classifies species by their extinction risk — from Least Concern to Extinct.

Keystone Species

A species that has a disproportionately large influence on ecosystem stability relative to its abundance. Removing a keystone species can cause an ecosystem to collapse.

Limiting Factor

An environmental condition (like temperature, water, or nutrients) that restricts the growth or distribution of an organism or population.

Migration

Seasonal movement of species from one region to another, often for breeding or food availability.

Mutualism

A type of symbiotic relationship in which both species benefit — for example, bees pollinating flowers.

Mutation

A change in an organism’s DNA that can introduce new traits and contribute to evolution.

Natural Selection

The process by which organisms better adapted to their environment are more likely to survive and reproduce, passing on advantageous traits.

Nutrient Cycling

The movement and recycling of essential elements like carbon, nitrogen, and phosphorus through ecosystems.

Niche

The specific ecological role or “job” of a species in its ecosystem, including its interactions, diet, and habitat.

Pollination

The transfer of pollen from the male to the female part of a flower, allowing plants to reproduce.

Population

A group of individuals of the same species living in a specific area at a given time.

Predation

An ecological interaction where one organism (the predator) hunts and consumes another (the prey).

Primary Productivity

The rate at which plants and other producers convert sunlight into chemical energy through photosynthesis.

Pollution

The introduction of harmful substances into the environment, negatively affecting living organisms and ecosystems.

Protected Area

A designated region managed for conservation, such as a national park or wildlife sanctuary.

Species

A group of similar organisms capable of interbreeding and producing fertile offspring.

Species Diversity

The variety and abundance of species within a given ecosystem. It considers both species richness and species evenness.

Species Evenness

The relative abundance of individuals among the species in an ecosystem — high evenness means populations are balanced.

Species Richness

The total number of different species present in a defined area or ecosystem.

Speciation

The formation of new species through evolutionary processes like natural selection and genetic isolation.

Succession (Ecological Succession)

The natural process by which ecosystems recover or develop over time, progressing from pioneer species to mature communities.

Sustainable Development

Development that meets current human needs while preserving natural resources and ecosystems for future generations.

Taxonomy

The scientific classification of organisms into hierarchical categories such as kingdom, phylum, class, order, family, genus, and species.

Trophic Level

A step in the food chain representing how an organism obtains energy — such as producer, primary consumer, or decomposer.

Tundra

A cold, treeless biome with permafrost soil, found mainly in Arctic and alpine regions.

Variation

Differences in traits among individuals of the same species, often arising from genetic differences or environmental influences.

Vulnerability (in conservation)

A measure of how likely a species or ecosystem is to experience decline or extinction due to human or natural pressures.

Wildlife Corridor

A natural or restored pathway that connects fragmented habitats, allowing animals to migrate and maintain healthy populations.

Wetland

An ecosystem where the land is saturated with water — such as marshes, swamps, and bogs — supporting rich biodiversity and providing flood control.

Conclusion

Biodiversity connects every living organism in a complex web of life. Each species, gene, and ecosystem contributes to the health of the planet. By understanding these scientific terms, we gain a deeper appreciation for Earth’s diversity and the urgent need to conserve it.

Glossary of Biodiversity