ORGANIZING LIFE’S DIVERSITY Chapter 17 Classification Organisms can be classified based on physical similarities.

Classification is… A way of grouping objects together based on similarities In the beginning---plants were grouped based on people who ate them— Edible Non-edible The history of the Tomato-1820 Colonel Robert Gibbon Johnson announced that at noon on September 26, he would eat a basket of tomatoes in front of the Salem NY courthouse—aka “love apple”

Scientists Who Developed Classification

Aristotle: Greek Philosopher Developed 1st method of classification Classified into 2 major groups Plants: herbs, shrubs or trees Animals: According to where they lived: land, water or air

Carolus Linnaeus Plants: based on reproductive structures Animals: based on evolutionary traits Selected physical characteristics based on close relationships of organisms

Carolus Linnaeus Invented the 2-word naming system to identify species called BINOMIAL NOMENCLATURE: Bi (2) Nomial (name) Scientific Name: Genus: 1st word: consist of closely related species Species: 2nd word: consist of description of the species.

Binomial nomenclature is a two-part scientific naming system. uses Latin words scientific names always written in italics two parts are the genus name and species descriptor

RULES OF BINOMAL NOMEMCLATURE Genus is ALWAYS capitalized & is 1st Species is ALWAYS lowercase & is 2nd BOTH ARE ITALICIZED OR UNDERLINED!!! Homo sapiens Felix tigerus F. leo F. domestica

A genus includes one or more physically similar species. Species in the same genus are thought to be closely related. Genus name is always capitalized. A species descriptor is the second part of a scientific name. always lowercase always follows genus name; never written alone Tyto alba

Subspecies Biologists refer to variations of a species that live in different geographic areas as subspecies A subspecies name follows the species identifier

Subspecies: Alabama Beach Mouse This mouse is one of several subspecies of old field mice which live only in coastal sand dune areas. Living isolated from other beach mice for thousands of years has allowed each subspecies to develop its own slightly unique characteristics suited to its particular beach environment. Peromyscus polionotus ammobates Other Subspecies: Perdido Key beach mouse, Choctawhatchee beach mouse, Santa Rosa beach mouse, and St. Andrews beach mouse. They differ from the ABM and each other in coloration and body size

Subspecies identifier

Many organisms have common names that can be misleading. SCIENTIFIC NAMES: Many organisms have common names that can be misleading. Example: a sea horse is a fish, not a horse. Also, it is confusing when a species has more than one common name.

Common Names All newly discovered species are given Latin names because it is no longer used Do not tell you how organisms are related or classified Can be misleading Confusion can occur when organisms have more than one name

Scientific names help scientists to communicate. Some species have very similar common names. Some species have many common names.

Taxonomy is… Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics Biologists who study taxonomy are called taxonomists

Taxonomists Is a useful tool in helping identify unknown species– if a child has eaten a mushroom & You do not know whether it is poisonous… Important to the economy- often discover new sources of lumber, medicines & energy…

Dichotomous Key Organisms can be identified easily by using a dichotomous key Animals around the world use the same identification system A Dichotomous key is made up of sets of numbered statements. Each set deals with a single characteristic of an organism, such as leaf shape or arrangement

Using a dichotomous key to identify money!

How are living things Classified? Felix tigerus

Linnaeus developed the scientific naming system still used today. Taxonomy is the science of naming and classifying organisms. White oak: Quercus alba A taxon is a group of organisms in a classification system.

Order of Taxa Domain, Kingdom, Phylum, Class, Order, Family, Genus, & Species Can you remember it this way? Do Kings Play Chess On Fine Glass Surfaces?

Important Facts Linnaeus version of hierarchy of organization was made of only 2 kingdoms-animals & plants Modern biologists adopted this system, but added several other kingdoms, as well as domains (categories above kingdoms)

3 Domains of Life The three domain names 1. Bacteria 2. Archaea 3. Eukarya All living things seem to be related by ancestry to one of these

Woese and the 6 Kingdoms Biologists Carl Woese proposed in 1977 a 6-kingdom system that divided the then 5 kingdom into two new kingdoms; Archaebactera and Eubacteria In 1990, Woese introduced the 3 domain system that is still used today

Domain Bacteria Oldest known fossils appear as bacteria Include prokaryotes in the Kingdom Bacteria one of largest groups on Earth classified by shape, need for oxygen, and diseases caused. Do not have a true nucleus Oldest known fossils appear as bacteria

Domain Archaea Includes prokaryotes in the Kingdom Archaea cell walls different from bacteria differences discovered by studying RNA Known for living in extreme environments (sulfur springs, deep-sea thermal vents, salty lakes…) Some produce methane (as waste) Some are Autotrophs Thought to be the earliest organisms on Earth

Domain Eukarya Includes all Eukaryotes: most familiar Kingdom Animalia Kingdom Plantae Kingdom Protista Kingdom Fungi Have true nucleus, complex cellular organelles

Linnaeus’ classification system has seven levels. Each level is included in the level above it. Levels get increasingly specific from kingdom to species.

Order of Taxa The smallest taxon is species. Organisms that look alike and successfully interbreed belong to the same species. The next largest taxon is a genus—a group of similar species that have similar features and are closely related Mountain lion

Taxonomic rankings Compare the appearance of a lynx, Lynx rufus, a bobcat, Lynx canadensis, and a mountain lion, Panthera concolor. Lynx Mountain lion Bobcat

Section 17.1 Summary – pages 443-449 Domain Eukarya Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Felidae Genus Lynx Species Lynx rufus Lynx canadensis Bobcat Lynx Section 17.1 Summary – pages 443-449

The Linnaean classification system has limitations. Linnaeus taxonomy doesn’t account for molecular evidence. The technology didn’t exist during Linneaus’ time. Linnaean system based only on physical similarities.

Physical similarities are not always the result of close relationships. Genetic similarities more accurately show evolutionary relationships.

Introduction to Classification

Cladistics is classification based on common ancestry. Phylogeny is the evolutionary history for a group of species. evidence from living species, fossil record, and molecular data shown with branching tree diagrams

Cladistics is a common method to make evolutionary trees. classification based on common ancestry species placed in order that they descended from common ancestor

A cladogram is an evolutionary tree made using cladistics. A clade is a group of species that shares a common ancestor. Each species in a clade shares some traits with the ancestor. Each species in a clade has traits that have changed.

basis of arranging species in cladogram Derived characters are traits shared in different degrees by clade members. FOUR LIMBS WITH DIGITS Tetrapoda clade 1 Amniota clade 2 Reptilia clade 3 Diapsida clade 4 Archosauria clade 5 EMBRYO PROTECTED BY AMNIOTIC FLUID OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW FEATHERS & TOOTHLESS BEAKS. SKULL OPENINGS BEHIND THE EYE DERIVED CHARACTER basis of arranging species in cladogram more closely related species share more derived characters represented on cladogram as hash marks

Nodes represent the most recent common ancestor of a clade. Tetrapoda clade 1 Amniota clade 2 Clades can be identified by snipping a branch under a node. Reptilia clade 3 Diapsida clade 4 Archosauria clade 5 FOUR LIMBS WITH DIGITS FEATHERS AND TOOTHLESS BEAKS. SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID DERIVED CHARACTER NODE

Molecular data may confirm classification based on physical similarities. may lead scientists to propose a new classification. DNA is usually given the last word by scientists.

Until 1866: only two kingdoms, Animalia and Plantae The tree of life shows our most current understanding. New discoveries can lead to changes in classification. Until 1866: only two kingdoms, Animalia and Plantae Animalia Protista Fungi Plantae 1866: all single-celled organisms moved to kingdom Protista 1938: prokaryotes moved to kingdom Monera Archea Bacteria 1959: fungi moved to own kingdom 1977: kingdom Monera split into kingdoms Bacteria and Archaea

6 kingdoms of life

6 Kingdoms of Life

Monerans Most of these environments are oxygen-free. The Monerans, are cells that lack a nucleus, are microscopic and unicellular some are chemosynthetic, where others are photosynthetic. Most of these environments are oxygen-free.

2 groups of Monerans Archaebacteria & Eubacteria Prokaryotic Organisms Unicellular Autotrophs & Heterotrophs Have a cell wall Reproduce by Binary Fission

Protists Some are plantlike some are animal-like Some are fungus-like

Protists are: Eukaryotic Unicellular Both Heterotrophs and Autotrophs Do Not Have a Cell Wall Reproduce Asexually & Sexually

Fungi Unicellular or multi-cellular eukaryote that absorbs nutrients from organic materials in the environment

Fungus are Eukaryotic Are Unicellular & Multicellular (only group that has that) Heterotrophs (decomposers) Have a Cell Wall Reproduce: Asexual, Fragmenting, Budding

Plants contain chloroplasts and have cell walls There are more than 250,000 known species of plants

Plants Eukaryotes Multicellular Autotrophs Have a Cell Wall Reproduce: Asexual, Sexual

Animals Animals are multicellular heterotrophs Nearly all are able to move from place to place. Animal cells do not have cell walls

Animals Eukaryotes Multicellular Heterotrophs No Cell Wall Reproduce: Asexual & Sexual