Classification & Unicellular Organisms

Taxonomy

The science of classifying and naming organisms

Evolutionary tree

A diagram that reflects evolutionary relationships among groups of organisms; species that are most closely related share a more recent common ancestor and are located closer on the tree

Binomial Nomenclature

A system for giving each organism a two-part scientific name that consists of the genus name followed by the species name; Linnaeus is credited with starting this naming system

Levels of Classification

Kingdom, Phylum, Class, Order, Family, Genus, Species

Kingdom

First and largest category used to classify organisms; there are six: Archaebacteria, Eubacteria, Protists, Fungi, Plants, & Animals

Genus

Group of closely related species; the first part of a scientific name that is always capitalized

Species

A group of organisms that are closely related and can mate to produce fertile offspring; the second part of a scientific name

Dichotomous Key

Step by step approach to identify an organism using a series of paired descriptions; allows you to determine the scientific name of an unknown organism based on its characteristics

Prokaryote

A unicellular organism that lacks a nucleus and membrane enclosed organelles; examples include: Archaebacteria & Bacteria

Eukaryote

An organism whose cell/cells contains a nucleus and membrane enclosed organelles; examples include: Protists, Fungi, Plants & Animals

Methanogens

A group of Archaebacteria that produce methane as a by product of their metabolism; live in swamps & our intestines

Extremophiles

Archaea that live in extreme environments; examples include: halophiles, thermophiles, & cryophiles

Halophiles

"Salt-loving" Archaea that live in environments that have very high salt concentrations (The Dead Sea)

Thermophiles

Archaea that thrive in very hot environments, such as volcanoes and hydrothermal sea vents

Cryophiles

Archaea that survive in unusually cold temperatures like the polar ice caps

Bacteria

Members of this kingdom are prokaryotic and unicellular; they can be pathogenic and make us sick, but they also do many helpful things too (decompose, digest food, make yogurt & cheese)

Binary Fission

Type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical cells; can occur very quickly in unicellular organisms (bacteria & protists)

Parasite

An organism that lives on or in a host and causes it harm; many types of bacteria & protists

Pathogen

An organism that causes sickness or disease; many types of bacteria & protists

Antibiotic

A chemical that kills bacteria or slows their growth without harming body cells

Beneficial Functions of Bacteria

Decomposition, Digestion, Make vitamins, Outcompete bad bacteria in/on us, Help plants use nitrogen, Make yogurt and bleu cheese, Used in Genetic Engineering to make human hormones like insulin and growth hormone

Protists

Members of this DIVERSE kingdom are eukaryotic; examples: amoeba, paramecium, euglena, algae, slime molds

Amoeba

A type of animal-like protist; unicellular, eukaryotic, heterotrophic, moves by pseudopods

Phagocytosis

Process by which amoeba engulf large particles of food and take them into the cell; "cell eating"

Paramecium

A type of animal-like protist; unicellular, eukaryotic, heterotrophic, moves by cilia

Contractile Vacuole

Cell structure that stores and then expels water from the cell; found in freshwater Protists; prevents them from bursting

Euglena

A type of plant-like protist; unicellular, eukaryotic, autotrophic, moves by a flagellum

Algae

Plant-like protists usually classified by their color: green, golden, red, brown (kelp); all are autotrophic and some can be multicellular; some glow and others cause problematic "red tides"

Slime molds and water molds

Fungi-like protists; heterotrophic, decomposers