CLASSIFICATION Chapter 18

CLASSIFICATION Chapter 18
Reference Text: Modern Biology Chapter 18 – Classification

BIG IDEA All Organisms on earth are said to have descended from an ancient common ancestor – the classification of all species reflects their relationship with many related species…

WHAT THINGS DO WE CLASSIFY?
History Of Taxonomy WHAT THINGS DO WE CLASSIFY? WHY DO WE CLASSIFY THEM? When things are sorted into groups it makes them easier to understand and it makes it easier to see the relationships between them.

Every Year, thousands of new species are discovered.
History Of Taxonomy Every Year, thousands of new species are discovered.

History Of Taxonomy To study so many life-forms, biologists organize or classify them into numerous groups based on their similar characteristics (structures). When things are sorted into groups it makes them easier to understand and it makes it easier to see the relationships between them.

WHAT IS Classification?
Classification: to group things according to similar/different structures that they share. Classification is very useful in Biology… Indicates relationships between species Accurately & uniformly names organisms; star fish and jelly fish aren't’ really fish Classification is a very broad term which simply means putting things in classes. Any kind of organisational scheme is a classification: for example, sorting smarties by colour, coins by diameter or cities by population. Humans seem unable to resist the urge to classify. It's one of the most basic activities of any science, because it's easier to think about a few groups of things than about lots of separate things.

Early systems of classification
TAXONOMY: The branch of biology that classifies organisms according to their characteristics and evolutionary history

TAXONOMISTS Taxonomists are scientists that identify & name organisms.

Taxonomists name things in a way that reflects their classification. They use the same language (Latin or some Greek) for all names. Panthera tigris What can you tell just by the scientific name of the tiger (genus, species Panthera tigris) and the jaguar? Panthera onca

The first classification system was developed 2000 years ago by Greek Philosopher Aristotle. He was the first taxonomist. Aristotle divided organisms into plants & animals He then subdivided them by their habitat - land, sea, or air dwellers

As more & more organisms began to be discovered, Aristotle’s system was no longer adequate for naming & organizing all life on earth. Also, scientists did not use a universally accepted method for classifying and naming organisms. Some used common names, others used long and complex scientific names Sea”horse”??

The “Father of Taxonomy”
Linnaeus’s System Carolus Linnaeus 1707 – 1778 In response to the need for better organization, an 18th century Swedish botanist named Carolus Linnaeus offered a solution to the confusion of classifying and naming organisms. Created a hierarchical system for classifying organisms Developed naming system still used today In response to the need for better organization, an 18th century Swedish botanist named Carolus Linnaeus offered a solution to the confusion of classifying and naming organisms. Carolus Linnaeus “God created, Linnaeus classified,” was his motto. Carolus Linnaeus, a Swedish born naturalist, published his book, "Systema Naturae" in which he outlined a method for classifying all organisms. This method is still in use today (generas, orders, classes and kingdoms). His views on evolution were rather tame. He believed that new species within genera came into being through hybridization, but only under the controlling hand of god. He also thought there was a divine order to all organisms and developed his classification system to reveal this order. The “Father of Taxonomy”

Linnaeus’s System Linnaeus classified organisms based on similarities in morphology (form & structure), rather than by location. For example, although Bats can fly, he classified them as mammals, not birds, because they share common traits with other mammals; they have hair, have live births and nurse their offspring with milk.

Linnaeus’s System The Linnaeus System of Taxonomy uses a hierarchical system for classifying organisms from broadest to most specific.. Called Levels of Classification! The two-part name Linnaeus gave each organism is a Latin, scientific name. This system of naming organisms is called binomial nomenclature, and it is still used today. Binomial means “consisting of two terms” and nomenclature means “a system of names”. There are two important features of this system:

Linnaeus’s System Linnaeus’s Seven-Level Classification System:
Kingdom, Phylum, Class, Order, Family, Genus, species Each category is called taxa, hence the name taxonomy!

Linnaeus’s Seven-Level Classification System:
Linnaeus’s System Linnaeus’s Seven-Level Classification System: Kingdom Phylum Class Order Family Genus Species BROADEST TAXON MOST SPECIFIC

Levels of Classification
Keep Plates Clean Or Family Gets Sick

Think about it Which two animals would be more closely related, two from the same phylum or two from the same genus?

Binomial nomenclature
Linnaeus’s System Linnaeus also developed the modern system of naming organisms known as: Binomial nomenclature The two-part name Linnaeus gave each organism is a Latin, scientific name. This system of naming organisms is called binomial nomenclature, and it is still used today. Binomial means “consisting of two terms” and nomenclature means “a system of names”. There are two important features of this system:

Oops! Common names can vary! Example: ______________ are all names for the same animal mountain lion puma catamou cougar

Also, some early scientific names were often long and difficult to remember… The European bee, for example, carried the name Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatis.

Linnaeus’s System Binomial nomenclature is a two-part naming system that identifies a species with 2 names: Uses Genus & species Either Latin or Greek Italicized in print Capitalize Genus, but NOT species Underline when writing Turdus migratorius The first word in binomial nomenclature is the name of the genus to which the organism belongs. The second word is the name of the unique species. A species is a group of similar organisms that are capable of producing fertile offspring with each other. Genus is a group that has one or more different species classified within it; these are closely related species that evolved from a common ancestor. American Robin

Binomial Nomenclature
Which TWO are more closely related? copyright cmassengale

Taxonomic Classification
Taxonomic Group: tiger grey wolf Kingdom: Animal Animal Phylum: Chordates Chordates Class: Mammals Mammals Order: Carnivores Carnivores Family: Felines Canines Genus: Panthera Canis Species: tigris lupus Name: Genus & species

modern PHYLOGENETIC taxonomy
REMEMBER: Organisms are classified together because they are similar; they are similar because they stem from a common ancestor. Woodchuck Squirrel The main goal of modern taxonomy is to make biological classification that reflect the organisms evolutionary history (phylogeny)…not just relatedness based on general similarities

Linnaeus focused on morphology or features of an organism when classifying it. Today we know that those features are largely influenced by genes, which are inherited, or passed down from our ancestors. The main goal of modern taxonomy is to make biological classification that reflect the organisms evolutionary history (phylogeny)…not just relatedness based on general similarities

Modern taxonomists classify the tremendous diversity of organisms based on how close their evolutionary relationships are with other living and once-living things. Linnaeous based his classification on the most evident characteristics. Organisms are classified together because they are similar; they are similar because they stem from a common ancestor

They all agree that the classification of an organisms should reflect their PHYLOGENEY Phylogeney: The evolutionary relationships between all groups of organisms based on ancestor/descendant relationships. The morphology Linnaeus followed holds true to phylogeny or evolutionary relationships in most cases….

Modern taxonomists construct a Phylogenetic tree, or family tree to show these relationships. The phylogenetic tree shows the evolutionary relationships between different groups of organisms. Evidence from morphological, biochemical, and gene sequence data suggests that all organisms on Earth are genetically related, and the genealogical relationships of living things can be represented by a vast evolutionary tree, the Tree of Life. The Tree of Life then represents the phylogeny of organisms, i. e., the history of organismal lineages as they change through time. It implies that different species arise from previous forms via descent, and that all organisms, from the smallest microbe to the largest plants and vertebrates, are connected by the passage of genes along the branches of the phylogenetic tree that links all of Life

Pangolin Armadillo The mammal that is most often confused with an armadillo is the pangolin (Order Pholidota). The pangolin looks fairly similar to an armadillo because they have very similar lifestyles — they both tear apart termite mounds and anthills with strong claws, they both have narrow noses and long tongues, they both have a protective “shell”, and both like to hide in the undergrowth to escape from predators. Aside from the fact that pangolins are found only in Africa and Asia, and armadillos are only found in the Americas, there is one easy way to tell them apart. Pangolins have a scaly appearance. They are covered with a layer of flat leaf-shaped plates made out of keratin, the same material that makes up your hair and fingernails. This “armor” surrounds the entire body of the pangolin. Armadillos have a shell made of bone that only covers the top of the body and the tail. Look at the pangolin photos below, and compare them with the armadillo photos shown elsewhere on this website. Note especially the close-up photo of the pangolin tail, and compare it with the close-up of the armadillo tail shown here. Can you tell the difference between these animals? Most of all of the pangolins ancestors are extinct.

modern PHYLOGENETIC taxonomy Four Types of evidence include:
Modern Taxonomist consider several lines of evidence when classifying organisms according to their evolutionary history: Four Types of evidence include: Morphology (homologous structures) Embryological development DNA, RNA, Amino acid sequences Fossil records

copyright cmassengale
Homologous Structures (BONES in the FORELIMBS) shows Similarities in the morphology of mammals. copyright cmassengale

Similarities in Vertebrate Embryos
copyright cmassengale

Similarities in DNA copyright cmassengale

Evidence found in the Fossil Record
copyright cmassengale

cladistics A relatively new system of phylogenetic classification is called cladistics. Based on Derived characteristics: Certain features that evolved only within the group being studied Example: if the group being studied is birds, having feathers is the derived character. For example, if the group being studied is birds, having feathers is the derived characteristic. Birds are the only animals with feathers, so it is safe to say that feathers evolved within the bird group and were not inherited from a distant ancestor of birds. So, sharing derived characteristics is a strong indicators of common ancestry.

cladistics In this approach, ancestry diagrams are made through derived characters analysis. These diagrams called CLADOGRAMS Cladograms show common ancestry, but do not indicate the amount of evolutionary "time" separating taxa Each diagonal line represents an organism. These lines have traits coming off of that line. These traits indicate a shared characteristic that all the organisms that follow that line share. This also means that the organisms behind do not possess this trait. The hagfish is the most primitive and lacks all the traits, based on this tree.

Primate Cladogram copyright cmassengale

TWO MODERN SYSTEMS of Classification
Aristotle classified organisms as either plants or animals.. Linnaeus took it a step further and classified organisms into more specific groups such as class, order, family, genus and species. Since the time of Linnaeus, scientists have discovered many new species and uncovered a wealth of information about known species. As a result, Biologists created more than two kingdoms of living things.

TWO MODERN SYSTEMS of Classification
…some organisms don't quite fit into the plant or animal group. As a result, several other kingdoms of organisms are now used. Today's scientists look at cell structure, how the organism moves, gets food, and reproduces to place it in the correct kingdom. Since the time of Linnaeus, scientists have discovered many new species and uncovered a wealth of information about known species. As a result, Biologists created more than two kingdoms of living things.

Six Kingdom System Three Domain System
TWO MODERN SYSTEMS of Classification Two Current Classification Systems Six Kingdom System Three Domain System Since the time of Linnaeus, scientists have discovered many new species and uncovered a wealth of information about known species. As a result, Biologists created more than two kingdoms of living things.

MODERN SYSTEMS of Classification Old Five Kingdom System:
Monera include all prokaryotic organisms, which are all unicellular life forms that lack a true nucleus. Protista, Fungi, Plantae,Animalia include all eukaryotic organisms, which are all life forms that do contain a true nucleus and various organelles.

MODERN SYSTEMS of Classification The NEW Six Kingdom System:
Archaebacteria & Eubacteria include all prokaryotic organisms, which are all unicellular life forms that lack a true nucleus. Protista, Fungi, Plantae,Animalia include all eukaryotic organisms, which are all life forms that do contain a true nucleus and various organelles.

The six kingdoms FUNGI ANIMALIA PLANTAE PROTISTS EUBACTERIA
In the six kingdom system, the Monera are split into two separate kingdoms of Prokaryotic organisms based on important differences between them EUBACTERIA ARCHAEBACTERIA

The Three domain system
Broadest, most inclusive taxons are the Three Domains Archaea, Bacteria, and Eukaryota The three domain system highlights the importance of archaebacteria as a lifeform.

Six-Kingdom System Three-Domain System
The main criteria of grouping here is Eukaryotic vs. Prokaryotic REMEMBER: These systems are not etched in stone! They have been revised over the years, and will continue to be revised when new evidence is discovered.

Modern humans are classified as Homo sapiens. Homo is Latin for “human”; sapiens means “wise” Homo habilis is thought to be one of the first known ‘humans’. copyright cmassengale

The Three domain system copyright cmassengale
Domain – Archaea Kingdom - ARCHAEBACTERIA Probably the 1st cells to evolve Live in HARSH environments Found in: Sewage Treatment Plants (Methanogens) Thermal or Volcanic Vents (Thermophiles) Hot Springs or Geysers that are acid Very salty water (Dead Sea; Great Salt Lake) – Halophiles Chemosynthesis: use inorganic compounds to make food. Archaebacteria that live in deep-sea vents carry out a process similar to photosynthesis. This process is called chemosynthesis. Instead of sunlight energy, they use chemical energy to make their own food. copyright cmassengale

Kingdom - ARCHAEBACTERIA
Hot Springs Acid mine drainage Sulfur Springs The Dead Sea

Domain - Bacteria Kingdom - EUBACTERIA Some may cause DISEASE Found in ALL HABITATS except harsh ones Important decomposers for environment Commercially important in making cottage cheese, yogurt, buttermilk, etc. (Acidophilus). Eubacteria (formerly within Monera) are unicellular prokaryotic organisms. These bacteria include all other types of bacteria, including disease causing varieties as well as many harmless types. These "true" bacteria (prefix eu meaning true) are found practically in all the environments. In fact, it is difficult to name any place where eubacteria are not found. When people talk about ‘bacteria’ they are usually talking about this group. copyright cmassengale

Kingdom - EUBACTERIA One type of bacteria, the blue-green bacteria, contains chlorophyll. Blue-green bacteria are unusual because they can carry out photosynthesis. The process of photosynthesis carried out by bacteria is similar to the photosynthesis in plants. copyright cmassengale

Live in the intestines of animals copyright cmassengale

Domain Eukarya is Divided into 4 Kingdoms: Protista (protozoans, algae…) Fungi (mushrooms, yeasts …) Plantae (multicellular plants) Animalia (multicellular animals) copyright cmassengale

Domain: Eukarya Kingdom: Protista Most are unicellular Some are multi-cellular Some are autotrophic, while others are heterotrophic Aquatic The kingdom Protista consists of another group of simple organisms. They are different from bacteria because they have nuclei in their cells. Protista include both eukaryotic unicellular and eukaryotic multicellular organisms. Protists come in all shapes and sizes. Some have only one cell. Others have more than one cell. Some protists carry out photosynthesis. Others must take in food to get energy. Protists can reproduce both sexually and asexually. Protists are found in aquatic or damp environments. The Protozians (proto meaning “first” and zoa meaning “animal”) are either free-living or parasitic. Scientists think that Protists probably gave rise to all other eukaryotic organisms copyright cmassengale

Domain: Eukarya Kingdom: Protista Fungus Like – made of threadlike fibers The three main groups of protists are the protozoans, the algae, and the slime molds. The kingdom Protista consists of another group of simple organisms. Animal Like – move around and eat other organisms Plant Like – contain chlorophyll for photosynthesis copyright cmassengale

Domain: Eukarya Kingdom: Fungi Multicellular, except yeast Absorptive heterotrophs (digest food outside their body & then absorb it) Cell walls made of chitin Fungi are not plants. They do not have chlorophyll in their cells. However, each of their cells does have a nucleus and other cell parts. They also have specialized cells.

Domain: Eukarya Kingdom: Plantae Multicellular Autotrophic (except for carnivorous plants) Absorb sunlight to make glucose – Photosynthesis Cell walls made of cellulose Growth, with increases in size and number of cells, is part of development. DThe Plantae are all eukaryotic, multicellular autotrophic organisms. Plant cells contain chlorophyll within chloroplasts, which are needed for the production of food (glucose) through photosynthesis. Plants have a life cycle that includes a sexually reproducing generation and an asexually reproducing generation; this is known as alternation of generations. evelopment involves many stages from conception until death.

Mosses Liverworts Angiosperms Gymnosperms Ferns

Domain: Eukarya Kingdom: Animalia Multicellular Ingestive heterotrophs (consume food & digest it inside their bodies) Feed on plants or animals Most animals reproduce only sexually, although some animals do reproduce asexually (parthenogenesis). Parthenogenisis is a form of reproduction in which the ovum develops into a new individual without fertilization. All offspring produced by some types are identical in all inherited respects to the mother. Natural parthenogenesis has been observed in many lower animals, especially insects.

Kingdom Cell Type Nutrition Archaea Archaebacteria Prokaryote Unicellular Both autotroph and heterotroph Bacteria Eubacteria Both Eukarya Protists Eukaryote Fungi Heterotroph Plantae Multicellular Autotrophic (mostly) Animalia copyright cmassengale

Methanogens, Thermophiles, Acidophilles

The six kingdoms

The VIRUS – IS IT ALIVE? Characteristics Cell Virus Growth yes No
Homeostasis Yes Metabolism Mutation Yes; necessary for its survival Genetic Material DNA, RNA Reproduction Yes by mitosis *Yes; but only possible when inside a host cell Structure Cytoplasm, membrane bound organelles, nucleus

Dichotomous key Biologists have developed a precise method to help them classify and identify unknown organisms. The classification tool called a dichotomous key Used to identify organisms Characteristics given in pairs Read both characteristics and either go to another set of characteristics OR identify the organism

Dichotomous key 1a Tentacles present – Go to 2 1b Tentacles absent – Go to 3 2a Eight Tentacles – Octopus 2b More than 8 tentacles – 3 3a Tentacles hang down – go to 4 3b Tentacles upright–Sea Anemone 4a Balloon-shaped body–Jellyfish 4b Body NOT balloon-shaped - 5 Each dichotomous key is composed of a list of observable, altering characteristics that leads, step-by-step, to the correct identification of the organism. The term dichotomous means “dividing in two” and refers to the fact that there are always two choices to pick from at every step. At each step, one of the two descriptions is eliminated, which

CLASSIFICATION Chapter 18

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