Diversity Of Living Things

Prokaryotic

Organisms whose cells do not have a nucleus or membrane-bound organelles. Examples include bacteria.

Eukaryotic

Organisms whose cells contain a nucleus and other membrane-bound organelles, typically more complex than prokaryotic cells.

Bacteria

Unicellular, prokaryotic organisms that can be found in almost every environment on Earth, exhibiting diverse nutritional modes.

Eubacteria

A kingdom composed of prokaryotic organisms with cell walls containing peptidoglycan; the most abundant type of bacteria.

Archaebacteria

A kingdom of prokaryotic organisms that often live in extreme environments; they have different cell wall compositions than eubacteria.

Fungi

Eukaryotic organisms that are mostly multicellular, heterotrophic, and obtain nutrients through external digestion.

Plantae

Multicellular, eukaryotic organisms that are autotrophic, generally possess cell walls made of cellulose, and perform photosynthesis.

Animalia

Multicellular, eukaryotic organisms that are heterotrophic, most capable of movement at some stage of life.

Protista

A diverse group of mostly unicellular eukaryotic organisms; some are autotrophic while others are heterotrophic.

Autotrophic

Organisms that produce their own food typically through photosynthesis or chemosynthesis.

Heterotrophic

Organisms that obtain their food by consuming other organisms; they cannot produce their own food.

Cocci

Spherical or round-shaped bacteria.

Bacilli

Rod-shaped bacteria.

Spirilla

Spiral-shaped bacteria.

Pseudopod

Temporary extensions of cytoplasm used for movement and feeding in certain eukaryotic cells, such as amoebas.

Cilia

Short, hair-like structures found on some eukaryotic cells, used for movement or moving substances over the cell surface.

Flagella

Long, whip-like structures used for movement in both prokaryotic and eukaryotic cells.

Dichotomous Key

A tool used to identify organisms based on a series of questions leading to a correct identification.

Gram Stain

A laboratory technique that differentiates bacterial species based on the composition of their cell wall.

Endosymbiotic Theory

The theory that eukaryotic cells evolved from prokaryotic cells through a symbiotic relationship.

Penicillin

An antibiotic discovered from the mold Penicillium that inhibits the growth of bacteria by interfering with cell wall formation.

Biodiversity

The variety of life on Earth, encompassing genetic, species, and ecosystem diversity.

Ecosystem Diversity

The variety of ecosystems in a given area, influenced by the physical environment and species interactions.

Antibiotic Resistance

The ability of bacteria to survive exposure to antibiotics, resulting from genetic variations within bacterial populations.

antibiotics

Chemical substances that inhibit the growth of or kill bacteria, used to treat bacterial infections.

bacteriophages

Viruses that infect and replicate within bacteria, often used in research and biotechnology applications.

binomial nomenclature

A system for naming organisms by using two Latin names: the genus (capitalized) and species (lowercase). Developed by Carl Linnaeus.

capsid

The protein shell that encases the genetic material (DNA or RNA) of a virus.

endospores

spores that are formed within the cells, mainly in bacteria. These spores are formed within bacteria vegetative cells or mother cells known as sporangia. Endospores ensure the survival of bacteria in adverse environmental conditions such as nutrient deficiency (carbon and nitrogen) and overpopulation.

facultative anaerobes

Organisms that can survive with or without oxygen, using oxygen when available but capable of anaerobic respiration when oxygen is absent.

host range

The range of host species that a pathogen or virus can infect or interact with.

lysis

The breaking down of a cell membrane, usually by viral infection, leading to the release of new viral particles.

lysogeny

A viral life cycle where the virus integrates its genetic material into the host cell's genome and remains dormant (latent) for some time before becoming active.

monera

A now-obsolete kingdom that included prokaryotic organisms, such as bacteria and cyanobacteria.

obligate aerobes

Organisms that require oxygen for survival and cannot survive in an anaerobic environment.

obligate anaerobes

Organisms that cannot survive in the presence of oxygen and must live in an anaerobic environment.

phylogeny

The evolutionary history and relationships among organisms or groups of organisms, often represented in a phylogenetic tree.

species

A group of organisms capable of interbreeding and producing fertile offspring, classified under a common name.

spores

Reproductive cells capable of developing into a new organism, often produced by fungi, plants, and some bacteria.

taxonomy

The science of classifying organisms into categories based on shared characteristics, including domain, kingdom, phylum, class, order, family, genus, and species.

vaccines

Preparations that stimulate the immune system to recognize and fight specific pathogens, often made from weakened or inactivated viruses or bacteria.

viruses

Infectious agents consisting of genetic material (DNA or RNA) encased in a protein coat, which require a host cell to replicate and cause disease.

angiosperms

Flowering plants that produce seeds enclosed within a fruit, part of the division Magnoliophyta.

chitin

A tough, flexible polysaccharide that forms the cell walls of fungi and the exoskeletons of arthropods.

cotyledon

The first leaf or leaves that appear during the development of an embryo in seed plants. Monocots have one, dicots have two.

dicots

Angiosperms (flowering plants) that have two cotyledons, net-like leaf venation, and vascular bundles in a ring.

gymnosperms

Non-flowering seed plants, such as conifers, that produce seeds exposed on cones, not enclosed in fruit.

lichen

A symbiotic association between a fungus and an alga or a cyanobacterium, often found growing on rocks, trees, or soil.

monocots

Flowering plants that have one cotyledon, parallel leaf venation, and scattered vascular bundles (e.g., grasses, lilies).

nonvascular

Plants that lack vascular tissue (xylem and phloem), such as mosses, and rely on diffusion for water and nutrient transport.

phloem

Vascular tissue responsible for transporting nutrients, particularly sugars, from the leaves to other parts of the plant.

rhizoids

Root-like structures in nonvascular plants (like mosses) that anchor the plant to the ground and absorb water.

saprophytes

Organisms, usually fungi or bacteria, that feed on dead or decaying organic matter.

sporangia

Specialized structures in plants, fungi, and some protists where spores are produced and released.

symbiotic relationship

An interaction between two different species where at least one benefits, and the other may benefit, be harmed, or remain unaffected (e.g., mutualism, parasitism, commensalism).

vascular

Plants with specialized tissues (xylem and phloem) for transporting water, nutrients, and food, such as ferns, conifers, and flowering plants.

xylem

Vascular tissue responsible for transporting water and dissolved minerals from the roots to the rest of the plant.

vertebrate

Animals with a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fish.

invertebrate

Animals that lack a backbone, such as insects, arachnids, mollusks, and crustaceans.

envelope

A lipid bilayer membrane that surrounds the protein coat (capsid) of some viruses, derived from the host cell membrane.

helical

A type of viral shape, in which the protein subunits of the capsid form a helical (spiral) structure around the genetic material.

icosahedral

A viral shape consisting of 20 triangular faces, resembling a polyhedron, commonly seen in many animal viruses.

immunity

The ability of an organism to resist infections or toxins through specific immune responses, often via antibodies or immune cells.

latency

A period in viral infections where the virus remains dormant within the host cell, not actively replicating but capable of reactivation.

vaccine

A substance used to stimulate the body's immune response to fight specific pathogens, often by using killed or weakened virus/bacteria.

virion

A complete, infectious form of a virus outside of a host cell, consisting of a nucleic acid core surrounded by a protein coat (capsid).

virus

An infectious agent composed of genetic material (DNA or RNA) encased in a protein coat, capable of replicating only within a living host cell.

biofilm

A slimy layer formed by colonies of bacteria or other microorganisms that adhere to surfaces and are often encased in a protective matrix.

cyanobacteria

Photosynthetic bacteria, often referred to as "blue-green algae," that produce oxygen and can live in a variety of environments, including aquatic and terrestrial.

extremophile

Organisms that thrive in extreme environmental conditions, such as high temperature, high salinity, or low pH.

flagella

Long, whip-like structures used by many bacteria and some eukaryotic cells for movement.

genetic transfer

The process by which genetic material is exchanged between organisms, such as horizontal gene transfer in bacteria or sexual reproduction in eukaryotes.

Gram-negative bacteria

Bacteria that have a thin peptidoglycan layer surrounded by an outer lipid membrane, which makes them resistant to certain antibiotics and stains pink in Gram staining.

gram-positive bacteria

Bacteria with a thick peptidoglycan layer and no outer lipid membrane, which stains purple in Gram staining.

plasmid

A small, circular DNA molecule found in bacteria that can replicate independently of chromosomal DNA and often carries genes for antibiotic resistance.

saprophytic

Organisms, such as certain fungi and bacteria, that feed on dead organic matter, playing a key role in decomposition.

nitrogen fixing bacteria

Bacteria that convert atmospheric nitrogen into forms usable by plants (e.g., Rhizobium species in legumes).

bioremedication

The use of microorganisms to degrade pollutants and toxins in the environment, helping to clean up contaminated sites.

insulin

A hormone produced by the pancreas that regulates blood sugar levels, often produced synthetically for diabetes treatment.

pathogen

Any microorganism (bacteria, virus, fungus, etc.) that causes disease in its host.

cone

The reproductive structure of gymnosperms, such as pines, which produces seeds.

flower

The reproductive structure of angiosperms, containing male and/or female reproductive organs (stamens and pistils).

fruit

 The mature ovary of an angiosperm plant, typically containing seeds, and often edible.

lignin

 A complex organic polymer found in the cell walls of plants, providing structural support and rigidity.

ovary

The female reproductive organ of a flower, which contains the ovules and, when fertilized, develops into a fruit.

vegetative reproduction

Asexual reproduction in plants, where new individuals are produced from non-reproductive parts, such as stems, roots, or leaves.

bryophyte

Nonvascular plants like mosses, liverworts, and hornworts that typically require a moist environment for reproduction.

endosperm

The tissue inside a seed that provides nourishment to the developing embryo.

nectar

A sugary  liquid produced by flowers to attract pollinators.

petal

The colorful part of a flower that attracts pollinators, often surrounding the reproductive organs.

pistil

The female reproductive part of a flower, consisting of the stigma, style, and ovary.

seed coat

The protective outer layer surrounding a seed.

sepal

The leaf-like structures at the base of a flower that protect the bud before it opens.

spermatophyte

Seed-producing plants, including both gymnosperms and angiosperms

stamen

The male reproductive part of a flower, consisting of the anther (where pollen is produced) and the filament.

tracheophyte

Vascular plants that have specialized tissues (xylem and phloem) for transporting water and nutrients.

genetic diversity

The total variation in genetic characteristics within a population, essential for survival and adaptation.

binary fission

A form of asexual reproduction in bacteria, where a single cell divides into two identical daughter cells.

Monera

The kingdom that once contained prokaryotes (bacteria and cyanobacteria), now split into separate domains (Bacteria and Archaea).

species diversity

The variety of different species present in a particular environment or ecosystem.