Biology 11 Taxonomy Unit

Main purpose: memorize and practice descriptions + characteristics of the following categories -Three domains -Kingdom characteristics -Taxonomy -Phylogenetics -Phylogeny

Domain Archaea

Definition: resemblance of the most ancient of life on Earth

Characteristics: Unicellular, prokaryotic, some autotrophs, some heterotrophs, primarily asexual, includes extremophiles

Examples: thermophiles, halophiles, methanogens

Domain Bacteria

Characteristics: unicellular, prokaryotic, enclosed organelles, some autotrophs, some heterotrophs, primarily asexual

Examples: E.coli, Salmonella, Streptococcus

Domain Eukarya

Description: a domain that contains all eukaryotic organisms that is divided into 7 conventional classifications:

Kingdom, phylum, class, order, family, genus and species

Characteristics: Eukaryotic

Kingdom Plantae

Characteristics: multicellular, eukaryotic, autotrophs, go through photosynthesis, both sexual and asexual reproduction, sessile

Possesses organelles specific to plants: a cell wall, chloroplasts, and large central vacuoles

Examples: moss, ferns, conifers, flowering plants

Kingdom Animalia

Characteristics: multicellular, eukaryotic, heterotrophs, reproduce sexually, motile

Examples: zebra, human, dog, fish, lizard, sponge, jellies, worms, etc.

Kingdom Fungi

Characteristics: unicellular, colonial, multicellular, eukaryotic, cell wall made up of chitin, heterotroph, sexual and asexual reproduction, sessile

Examples: toadstool, mushroom, mold, yeasts

Kingdom Protista

Description: the “catch-all” or “junk drawer” of kingdoms. Any life forms that don’t particularly fit anywhere else, are put into this kingdom

Characteristics: multicellular, unicellular, colonial, eukaryotic, heterotrophs and autotrophs, sexually and asexually reproduce

Examples: volvox, paramecium, seaweeds, etc.

Basis for Classifying Organsims

Organisms are classified into levels of taxa (taxon) based on structural similarities (similarities in DNA).

An organism’s classification reflects its evolution

Domains are divided into 7 categories:

-Kingdom

-Phylum

-Class

-Order

-Family

-Genus

-Species

Levels of Classification from Least Specific to Most Specific

Kingdoms: contain the fewest shared characteristics

Species: contain the smallest number of organisms with the greatest number of similarities

Nomenclature

The binomial system used to write scientific names

Consists of a genus name, followed by the species name, and may also include a third name following the species name. Both names are either underlined separately or italicized

Genus name: always capitalized

Species name: written in lowercase

Taxonomy

Classification of organisms that shows us where the species considered diverged from its relatives

Dichotomous Key

A tool used to identify an organism with the purpose of separating characteristics of similar appearing organisms to identify unknown species

Autotroph + heterotroph

Autotroph: converts inorganic molecules to organic molecules to obtain energy, making its own energy source

Heterotroph: Consume organic molecules to obtain energy

Eukaryotic + prokaryotic

Eukaryotic: cells possess a nucleus and membrane-bound organelles, but lack a cell wall

Prokaryotic: cells lack a nucleus and membrane-enclosed organelles

Multicellular + unicellular

Multicellular: consists of multiple interdependent cells

Unicellular: consists of one singular cell

Asymmetry

Lack of symmetry (regularity in a shape), irregularly shaped, tends to be sessile

Example: Sponge

Radial Symmetry

Body parts radiate out form a central point, organisms lack a true head, characterized by a top side and bottom side, tend to be slow-moving or sessile

Example: jellies (jellyfish), anemone, sea star (pentaradial symmetry)

Bilateral Symmetry

Characterized by two-sided symmetry, body parts repeat on either side of the organism if you were to cut it in half, two halves are mirror images of each other, and organisms tend to be more complex

Most organisms with a backbone tend to be bilateral, and efficient movers

Examples: Worms, snails, leach, most invertebrates, shellfish, lobster, humans

Dorsal

Upper surface of a bilateral animal

Ventral

Lower surface of a bilateral animal

Anterior

Head of a bilateral animal

Animals that have a central nervous concentrated at the head is termed cephalization

Posterior

Tail end of a bilateral animal

Oral

Mouth is present near the anterior (head) end of organism

Aboral

Mouth is present near the posterior (anus) end of organism

Phylogeny

Refers to the evolutionary history of a species or group of species, used to determine relationships between living things, patterns of descent/ ancestry, and correct classification of organisms

Phylogenetic Tree

1. common ancestor found at the base of the tree

2. Tips of branches represent species or other taxa

3. Branches meet at points called nodes that represent the common ancestor of the two taxa

4. Groups that share an immediate common ancestor are called sister groups

5. Ancestors plus all descendants form a clade

6. Branch that separates at the base is called an outgroup

Cladogram

Type of phylogenetic tree which may be constructed based on shared derived traits or synapomorphies

Advantages of using scientific names

1. A universally used name prevents miscommunication and confusion

2. The use of Latin names prevents changes in language

3. Many common names do not accurately represent organisms, inducing misunderstanding (Jellyfish ≠ fish)

4. Only one scientific name is used for each species

5. One scientific name refers to only a single species

Thermophiles

Bacteria that thrive in extremely hot environments

EX: volcanic springs, deep sea vents

Halophiles

Bacteria that inhabit in high salt environments

Methanogens

Bacteria that inhabit and thrive in environments with high amounts of methane

EX: sewage treatment plants, guts of cattle

Name the list classifying organisms

Domain, kingdom, phylum, class, order, family, genus, species

Acronym: (Dumb) Kids Play Catch Over Farmer Green’s Shed

Organic vs Inorganic molecules

Organic molecules: consist of carbon and hydrogen, both MUST be present

Example: Methane (CH4), Glucose (C6H12O6)

Inorganic molecules: lack either/or carbon or hydrogen

Example: Water (H20), Carbon dioxide (C02)

Synapomorphies

Shared traits that evolved only by members of the group that have been inherited from a singles common ancestor in which the features first evolved

Morphologies

Definition: Structural observation

Analogous + homologous

Analogous structures: species appear similar and have similar functions, but have different internal structures

Homologous structures: species appear different with different functions, but have similar internal structures

Convergent Evolution

Different populations of organisms are exposed to similar environmental selective pressures and similar structures form as a result