Taxonomy

Grouping Organisms

What is Taxonomy?

Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics.

A group of organisms is called a taxon (plural, taxa). The tool biologists use to accomplish this is

classification. Taxonomy can change

Biological Classification Systems

Aristotle (384-322 B.C.) Classified all organisms into two groups:

plants and animals. Using physical differences he further

classified them into smaller groups.

Why is standardization important?

Makes it easier to identify. Makes it easier to understand biological

diversity. Worldwide recognition. Useful for scientists working in agriculture,

forestry, and medicine. Beneficial for the economy.

Breaking It Down

Taxonomic ranking ranges from very broad characteristics to very specific ones.

Taxa from largest to smallest:

Domain,AND THEN: *Order

* Kingdom, *Family

*Phylum (similar classes), *Genus

*Class (similar orders), *Species (Remember: King Phillip Came Over for Good Soup)

From Domain to Species

Domain – Eukarya (broadest category). Kingdom – Animalia Phylum – Chordata (spinal cord). Class – Mammalia (mammal). Order – Carnivora Family – Felidae Genus – Lynx Species – Lynx rufus (Bobcat), Lynx canadensis (Lynx).

Six Biological Kingdoms

Kingdoms

The six kingdoms are determined by similarities such as: structure, behavior, DNA, location

.

From the most simplistic organisms to the most complex, the six kingdoms are:

Eubacteria (prokaryotes), Archaebacteria (prokaryotes), Protists (eukaryote), Fungi, Plants, Animals.

Phylogeny

Phylogenic classification uses evolutionary history to classify organisms.

Species that share a common ancestor also share an evolutionary history.

Reveals evolutionary relationships. Cladistics is a biological classification system that is

based on phylogeny. A cladogram is a model showing evolutionary

history.

Cladogram

Dichotomous Key

A tool that helps to classify organisms by narrowing down choices eventually leading to the correct answer.

Six Divisions of Life

Viruses

Non-living Parasitic Simple structure – Protein coat, capsid,

genetic material, & tails. Replication Cycles: Lytic & Lysogenic Cycle Viruses that affect humans – HIV (destroys

T- cell helpers), Herpes, Flu,Chicken Pox, & Shingles.

Eubacteria & Archaebacteria

Prokaryotes Biochemical differences Structural differences Arose from a common ancestor several billion

years ago.

Similarities & DifferencesArchaebacteria

Anaerobic Extremists 3 Types: Live in marshes, lake

sediments, & digestive tract of mammals – produce methane.

Live in extremely salty water like the Great Salt Lake in Utah.

Hot, acidic water of sulfur springs & hydrothermal vents.

Only asexual reproduction.

Eubacteria

Heterotrophs Live almost everywhere Autotrophs – Chemosynthetic

& Photosynthetic (Cyanobacteria).

Asexual reproduction – binary fission.

Sexual reproduction – conjugation.

Adaptations

Bacteria

Beneficial Help to fertilize fields –

nitrogen fixation. Recycle nutrients on Earth -

decomposers . Produce foods – cheese &

yogurt. Aids in digestion – providing

vitamins & enzymes. Produce antibiotics that

destroy other types of bacteria.

Harmful Bacteria cause disease in

plants & animals. Can enter through openings in

the skin, mouth, or nose. Can be carried in food, water,

or air. Can interfere with normal

bodily functions. Releases toxins that attack the

host.

Turn to page 498. Superbugs Defy Drugs.

Protists

The most diverse organisms of all kingdoms. Unicellular or multicellular. Are all Eukaryotes Heterotrophic or autotrophic Reproduce sexually, asexually, or through spores

depending on the type. Cause diseases – malaria & sleeping sickness.

Heterotrophic Protists

Animal-like (heterotrophic) protists are called protozoans. Grouped according to the way they move or grouped together

because they are parasites. Four main groups: Amoebas, Flagellates, Ciliates, &

Sporazoans. Amoebas – live in water, some are an important part of marine

plankton. Flagellates – Parasites that cause disease (sleeping sickness).

Beneficial to termites. Ciliates – paramecium, reproduces by conjugation. Sporazoans – Produce by spores, all are parasites, inernal

parasite, lives off of host in areas that has a nearby food supply. Ex –malaria.

Autotrophic Protists

Plantlike (autotrophs) Ex. – algae. Diatoms – phytoplankton. Lack roots, stems, or leaves.

Autotrophs produce much of the oxygen in Earth’s atmosphere.

Some are similar to fungi (slime molds, water molds, & downy mildews). Decompose a significant amount of organic material.

Algae are classified into six phyla: euglenoids, diatoms, & dinoflagellates are single cellular. Red, brown, & green are multicellular.

Fungi

Grow best in moist, warm environments. Most are multicellular. Basic structural unit is hyphae. Cell walls made of chitin. Some cause diseases & are poisonous. Are decomposers. Heterotrophs – Extracellular digestion. Reproduce asexually by fragmentation, budding, or

producing spores; sexually when haploid hyphae from compatible mycelia grow together.

Plants

Multicellular eukaryote. Thick cell walls made of cellulose. Autotrophs Photosynthesis - Needs water, sunlight, & carbon

dioxide. Has stems, leaves, & roots. Sexual reproduction through seeds or spores. Vascular (most plants. Grasses, & trees) &

nonvascular hornworts & liverworts).

Animals

Eukaryotic, multicellular organisms. Cells have cell membranes, instead of cell walls. Heterotrophic Sexual reproduction Specialized cells that form tissues & organs. Specialized cells that enable them to sense & seek

out food & mates, & allow them to identify & protect themselves from predators.

Symmetry