Life Sciences: Biosphere, Ecosystems, and the History of Life

A comprehensive set of vocabulary flashcards covering South African biomes, ecosystem terminology, biological cycles, classification systems, fossil evidence, and the chemistry of life.

Biosphere

The part of the Earth that can sustain life, composed of the atmosphere, hydrosphere, and lithosphere.

Biome

A large area with a certain climate and certain species of plants and animals that interact with each other.

Ecosystem

Different communities of plants and animals interacting with each other and with their physical (non-living) environment.

Population

A group of organisms of the same species, living in a specific area at the same time.

Community

All the populations of all different species in a particular place.

Species

A group of organisms of the same kind, which can breed with one another and produce fertile offspring.

Niche

The functional role that an organism plays within an ecosystem, determined by the biotic and abiotic factors.

Atmosphere

The layer of gases that keeps the environment stable and provides gases like $O_2$, $H_2$, $CO_2$, and $N_2$ for biological processes.

Hydrosphere

The aquatic or water part of the biosphere, including oceans, rivers, and lakes.

Lithosphere

The outside crust of the Earth formed of rocks and soil; a source of mineral ions for living organisms.

Phytoplankton

Microscopic plant-like organisms, such as algae, that can photosynthesize in the open sea.

Zooplankton

Animal-like organisms found in the open sea; some are visible with the naked eye but most are microscopic.

Estuaries

The meeting places of the rivers and the sea where fresh water meets salt water.

Wetlands

Areas with waterlogged soils or shallow water that act as flood controllers, filters for water quality, and wildlife habitats.

Savanna

A South African biome found in areas like Limpopo and Mpumalanga, characterized by sandy soil, woody plants, and animals like lions and elephants.

Fynbos Biome

A biome unique to South Africa comprising at least $8785$ species of flowering plants, of which $68\%$ are endemic.

Biotic Factors

The living components of an ecosystem, such as plants, animals, and micro-organisms.

Abiotic Factors

The non-living components of an ecosystem, such as soil, water, temperature, and sunlight.

Symbiosis

The interaction of living together, categorized into mutualism, commensalism, and parasitism.

Mutualism

A symbiotic relationship where both organisms benefit, such as a flower and a bee.

Commensalism

A symbiotic relationship where one organism benefits and the other is not affected, such as an orchid and a tree.

Parasitism

A symbiotic relationship where the parasite benefits and the host is harmed, such as humans and tapeworms.

Autotrophs

Also known as producers; organisms that make their own food using sunlight, $CO_2$, and $H_2O$ through photosynthesis.

Hydrophytes

Plants that grow in water, such as Elodea and water lilies.

Mesophytes

Plants that need a moderate supply of water, light, and temperature, such as marula and fig trees.

Xerophytes

Plants adapted to grow in very dry regions, such as cacti and aloes.

Heterotrophs

Also known as consumers; organisms that cannot make their own food and must eat other organisms.

Saprophytes

Also known as decomposers; organisms like fungi and bacteria that break down dead organic matter and return nutrients to the soil.

Aspect

The direction a slope faces, which determines the amount of solar radiation, heat, and evaporation the area receives.

Humus

Dead and decaying plant and animal material that makes soil fertile and provides nutrients.

Nitrogen Fixation

The process where bacteria or lightning allow atmospheric $N_2$ to form nitrates that plants can absorb.

Nitrification

The conversion of ammonia into nitrites and then nitrates by nitrifying bacteria in the soil.

Ectothermic

Also known as cold-blooded animals; those that cannot regulate their own body temperature internally, such as fish and reptiles.

Endothermic

Also known as warm-blooded animals; those that regulate their own body temperature, such as mammals and birds.

Hibernation

A state of reduced activity and winter "sleep" practiced by animals like snakes and rodents.

Aestivation

A state of summer inactivity and summer "sleep" practiced by animals like snails and insects.

Trophic Levels

Feeding levels in an ecosystem used to group organisms based on how they obtain energy.

Indigenous Species

Species that occur naturally in a particular area or country.

Endemic Species

Indigenous plants and animals that are found only in a particular area and nowhere else in the world.

Binomial Nomenclature

The two-part Latin naming system consisting of Genus and species, introduced by Carolus Linnaeus.

Prokaryotic

Unicellular organisms lacking a true nucleus and membrane-bound organelles, such as bacteria.

Eukaryotic

Organisms, often multicellular, that have a true nucleus and membrane-bound organelles.

Mass Extinction

An event where a large number of plant and animal species die over a large area at the same time.

Palaeontology

The study of fossils to provide evidence of early life forms, climate, and environment.

Archaeopteryx

A transitional fossil that is half bird and half reptile.

Coelocanth

A living fossil found in South Africa that is considered a link between terrestrial and aquatic organisms.

Pangaea

The single giant supercontinent that existed approximately $250$ million years ago.

Gondwanaland

The southern landmass formed after the split of Pangaea, including South America, Africa, Australia, Antarctica, and India.

Inorganic Compounds

Compounds that do not contain carbon and are not produced by living organisms (except $CO_2$ and $CO$).

Organic Compounds

Compounds containing carbon produced by living organisms, including carbohydrates, lipids, and proteins.

Saccharide

The building block (monomer) of carbohydrates, which can be single rings (monosaccharides) or bonded chains.

Glycosidic Bond

The chemical bond used to link saccharides together in polysaccharides.

Ester Bond

The chemical bond that joins one glycerol molecule to three fatty acids to form a lipid.