B4.2 Ecological Niches Kognity

Vocabulary flashcards covering key terms from sections on ecological niches, interactions, respiration types, nutrition modes, archaea diversity, and niche theory.

Ecological niche

The role of a species in an ecosystem — what it does, how it interacts with others, and its impacts — not just where it lives.

Biotic factors

Living parts of an ecosystem, including competition, disease, predators, and parasites.

Abiotic factors

Non-living parts of an ecosystem, such as temperature, precipitation, wind, sunlight, pH, and soil.

Specialist species

A species with a narrow set of environmental requirements or a limited diet (e.g., koala relying on eucalyptus leaves).

Generalist species

A species able to survive in a broad range of environments and use a variety of resources.

Obligate anaerobe

An organism that can only respire without oxygen; oxygen is toxic to it.

Facultative anaerobe

An organism that can respire with or without oxygen, often growing better in the presence of oxygen.

Obligate aerobe

An organism that requires oxygen for respiration.

Ecosystem engineer

An organism that creates or modifies habitats, such as beavers building dams that create wetlands and increase biodiversity.

Photosynthesis

Autotrophic process where light energy is used to convert CO2 and H2O into glucose and O2.

Chloroplast

Organelle in plant cells with photosynthetic pigments; site of photosynthesis.

Autotroph

An organism that produces its own organic matter from inorganic sources (producers).

Heterotroph

An organism that obtains its organic nutrients by consuming other organisms (consumers).

Photosynthesis equation

6 CO2 + 6 H2O → C6H12O6 + 6 O2.

Holozoic nutrition

Nutrition in which organisms take in solid or liquid food and digest it internally.

Mixotrophic nutrition

Having both autotrophic and heterotrophic modes of nutrition; can be facultative or obligate.

Saprotrophic nutrition

Organisms secrete enzymes to decompose dead organic matter, recycling nutrients (e.g., fungi, some bacteria).

Archaea

A domain of unicellular organisms with biochemistry distinct from bacteria, often extremophiles; no peptidoglycan in cell walls.

Chemoautotroph

Autotrophs that obtain energy by oxidizing inorganic compounds (e.g., sulfur compounds) and fixing CO2.

Photoautotroph

Autotrophs that use light energy to fix carbon and produce organic matter.

Three-domain system

Classification of life into Bacteria, Archaea, and Eukarya.

Halophile

An archaeal organism that tolerates very high salt concentrations.

Thermophile

An archaeal organism that thrives at high temperatures.

Hominidae

The biological family that includes humans and the great apes.

Hominins

Modern humans and their immediate ancestors.

Homo sapiens

Modern humans; existed about 300,000 years ago to the present; omnivorous and widespread.

Homo floresiensis

‘Hobbit’; a small hominin from Flores, Indonesia, ~100,000–50,000 years ago; about 107 cm tall.

Dental microwear

Tooth wear patterns used to infer past diets and trophic levels; isotope analysis also informative.

Fundamental niche

The full range of environmental conditions under which a species could live and reproduce.

Realised niche

The actual conditions under which a species exists, narrowed by biotic interactions like competition.

Competitive exclusion principle

Two species cannot coexist indefinitely if they occupy the same niche (Gause’s law).

Niche partitioning

Evolutionary differentiation that allows similar species to coexist by using different resources or times/spaces.

Spatial partitioning

Niche partitioning by occupying different physical spaces or heights.

Temporal partitioning

Niche partitioning by being active at different times.

Adaptations of herbivores

Specialized teeth and jaws (e.g., incisors for cutting, molars for grinding) and features like diastema to aid plant feeding.

Epiphyte

A plant that grows on another plant, not rooted in soil, obtaining moisture from the air.

Strangler epiphylte

An epiphytic fig that starts on a host tree and can strangulate it by growing roots downward.