UNIT 4 TAXONOMY AND CLASSIFICATION

Transcription

1 UNIT 4 TAXONOMY AND CLASSIFICATION CHAPTER 13 IN TEXT READ P.

2 4.0 CLASSIFICATION AND TAXONOMY 4.1 Define taxonomy 4.2 Discuss the reasons for classifying organisms 4.3 Define species and binomial nomenclature 4.4 Describe Carolus Linnaeus classification system 4.5 Define taxon and list the levels in order from broadest to the most specific 4.6 Describe the five kingdom system and the characteristics associated with each kingdom 4.7 Discuss the problems with the five kingdom system and the recent taxonomic solution 4.8 Describe the three domain system and the characteristics associated with each domain 4.9 Define dichotomous keys and their importance in identifying organisms

3 Taxonomy is the science of classifying all species of organisms, extinct and living. It is important because of the great diversity of organisms. Some organisms appear similar, some have similar functions, and some are genetically related but look different.

4 SPECIES One definition for a species is a related group of organisms that share a more or less distinctive form and are capable of interbreeding. This is the most popular definition in Biology, however, even this definition is under debate since a large number of organisms do not interbreed but rather reproduce asexually.

5 NAMING AND CLASSIFYING ORGANISMS There are well over 2 million different types of organisms known. Biologists place the organisms into groups based on their characteristics. By classifying, biologists can organize living things into groups. The system of naming we use today was created over 300 years ago by Carolus Linneaus (Father of Classificatrion) The Linnean system is very simple to use and became popular as a result

6 NAMING ORGANISMS Many of the names are based on the Latin or Greek since that is what was used when the naming system was created. The names often reflect the characteristics of the organisms, or in some cases honour the discovering scientist Scientists are required to give new latin scientific names when they discover new species

7 BINOMIAL NOMENCLATURE Binomial = 2 terms Nomenclature = naming System of naming species using a two-term name First term is the genus name Second term is species name Rules for naming 1. The genus name is capitalized 2. The second name is the species and is entirely lower-case 3. The name must be either in italics or have each term separately underlined

8 BINOMIAL NOMENCLATURE EXAMPLES CORRECT WAY Canis familiaris house dog WRONG WAY Canis Familiaris OR Canis lupus Wolf canis lupus Many species may be in the same genus because they are related, in this case dog-like animals Canis latrans - Coyote Canis lupus

9 The wolf Canus lupus is not endangered. Canus lupus has 39 subspecies. Some of these subspecies are threatened. Canus lupus lupus Canis lupus familaris Canis lupus dingo Domestic Dog

10 BENEFIT OF UNIVERSAL NAMING A universal system of naming allows us to avoid the confusion associated with common names, and tells us something about evolutionary relationships. Eg. A plant species May have 2 common names dependant where you live Bullrush cattails Ptarmigan grouse Larch - tamarack Eg. Common names give you misleading info on species classification, causes confusion. Catfish shellfish Starfish crayfish Eg. This system uses Greek and Latin this avoids miscommunication = no matter what language you speak every scientist will know what a Homo sapien is.

11 The genus name can be abbreviated to its initial letter, but never omitted, (as H. sapiens) when repeated or when several species from the same genus are being listed or discussed in the same paper or report.

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13 EACH ORGANISM IS FIRST CLASSIFIED INTO A DOMAIN. These 3 domains are divided by cell plan type: Prokaryotic Eukaryotic 1. Domain Bacteria Kingdom Bacteria Earliest living organisms, 1000 s of species exist today 2. Domain Archaea Kingdom archaea Evolved later, through a series of changes in bacteria 3. Domain Eukarya Kingdoms protista, plantae, animalia and fungi Early protists branched away from bacteria, giving rise to all the other kingdoms

14 2016 Pearson Education, Inc. ANIMATION: CLASSIFICATION SCHEMES video

15 2 KINGDOMS TO THE 6 KINGDOM CLASSIFICATION SYSTEM WE USE TODAY With increased travel, increased technology scientists have discovered new species that did not fit nicely into Aristotle's 2 kingdoms changes needed!

16 ROAD TO 6 KINGDOM CLASSIFICATION We often tend to organize things based on physical characteristics Music, clothing, books The groupings reflect the patterns we see in the world around us Aristotle first grouped over 1000 organisms into 2 large kingdoms, then subdivided each into smaller groups 1. KINGDOM ANIMALIA Grouped based on movement: on land in the air in water 2. KINGDOM PLANTAE Grouped based on physical characteristics Reproductive structures Types of external tissues

17 2016 Pearson Education, Inc. CLASSIFICATION: A WORK IN PROGRESS In the mid-1900s, the two-kingdom system was replaced by a five-kingdom system that placed all prokaryotes in one kingdom and divided the eukaryotes among four other kingdoms. ** with technology scientists have discovered single cellular prokaryotic organisms living in extreme environments ( salt, acidic and volcanic environments) prokaryotes now 2 kingdoms. (Monera and Archeabacteria) **The domain Eukarya is currently divided into kingdoms, but the exact number of kingdoms is still under debate. (Protista)

18 ROAD TO 6 KINGDOMS 3. KINGDOM PROTISTA Discovery of microorganisms forced scientists to reconsider Aristotle s system of classification Some organisms move like animals, but photosynthesize like plants

19 ROAD TO 6 KINGDOMS 4. KINGDOM FUNGI Were originally included in the plant kingdom Were placed in their own kingdom because they do not photosynthesize, and absorb nutrients from their environment

20 INVENTION OF MICROSCOPE NEW KINGDOM 5. Kingdom Bacteria Entirely made up of prokaryotic cells (lacking a nucleus and membrane-bound organelles) Obtain energy from a wide range of environments, but thrive between 10 and 40 degrees celcius Also called: Monera, eubacteria (true bacteria)

21 ROAD TO 6 KINGDOMS 6. KINGDOM ARCHAEA Also made up of prokaryotic cells, but with specialized structures allowing them to live in extreme environments Hot vents, acidic lakes, high pressure, low oxygen, etc. Also called: archaebacteria

22 Today, the above five kingdom system is not ideal or realistic for the diversity of organisms. There exist two problems, Kingdom Monera and Kingdom Protista. Kingdom Monera is the group of organisms that have been around since four billion years and, as a result, their long existence has led to evolutionary adaptation and the greatest metabolic diversity. Scientists have added a taxon broader than Kingdom and, therefore, placed above Kingdom. This grouping is called the Domain, of which there are currently three recognized. 3. The third domain is Domain Eukarya and includes all organisms composed of eukaryotic cells. For example, Kingdom Fungi, Plantae, and Animalia. 1. Domain Eubacteria include "true" bacterial organisms that are prokaryotic and contain cell walls composed of peptidoglycan. 2. Domain Archaea include bacterial prokaryotic organisms whose cell walls are composed of a different substance. By adding these two domains, the bacteria and prokaryotic organisms are better classified based on their overwhelming characteristics.

23 Copyright 2010 Ryan P. Murphy

24 FIGURE Domain Bacteria Earliest organisms Domain Archaea The protists (multiple kingdoms) Kingdom Plantae Domain Eukarya Kingdom Fungi Kingdom Animalia

25 Paradigm Shift 5 to 6 Kingdom Classification System 1. Kingdom Monera (Bacteria): Unicellular prokaryotic organisms that are the simplest in structure but display the greatest metabolic diversity. 2. Kingdom Fungi: Mostly multicellular eukaryotic organisms that contain cell walls and are absorptive heterotrophs (consume organic molecules) 3. Kingdom Plantae: Multicellular eukaryotic organisms that contain cell walls and are autotrophic (consume CO 2 ) 4. Kingdom Animalia: Motile multicellular eukaryotic organisms, without cell walls, and are ingestive heterotrophs. 5. Kingdom Protista: Multicellular or unicellular eukaryotic organisms with diversity in their nutrition. 6. Kingdom Archaebacteria : unicellular prokaryotic organism living in extreme environments.

26 Living Things Domain Bacteria Domain Eukarya Domain Archaea Kingdom Kingdom Kingdom Kingdom Kingdom Kingdom Bacteria Protista Fungi Plantae Animalia Archaea

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28 Problems with Kingdom Protista latest divide and problems with kindgoms! The protists are eukaryotic and, therefore, are included under Domain Eukarya. However, the problem with the protists is that they are a "dumping ground" for any eukaryotic organisms that does not fit as a Fungus, plant or animal. The result is a large group of organisms making up Kingdom Protista with no specific characteristic except that they are eukaryotic. For example, they may be unicellular or multicellular, autotrophic or heterotrophic, with cell walls or without. Scientists have patched this problem by dividing Kingdom Protista into several new and different Kingdoms. They are: Kingdom Archaezoa Kingdom Euglenozoa Kingdom Alveolata Kingdom Stramenopila: the brown algae Kingdom Rhodophyta: the red algae Even this is not a fix because current debate exists over the green algae. Should they be in their own Kingdom as the brown algae and red algae are, or should they be placed with Kingdom Plantae because of their close relationship with green plants?

29 Hierarchy of Taxa Still a changing science, the taxonomy of today is shown below. Domain Archaea Eubacteria Eukarya Kingdom Numerous Numerous 1. Archaezoa 2. Euglenozoa 3. Alveolata These are new! 4. Stramenopila 5. Rhodophyta 6. Fungi 7. Plantae Older Taxa 8. Animalia

30 TAXONOMY Carolus Linneaus (Father of Classification)

31 HIERARCHY OF GROUPS The Taxa Each kingdom is subdivided into smaller and smaller groups called taxa (one taxon) Kingdoms are the largest taxa, containing 1000 s of species Species are the smallest taxa, containing only one type of organism Domain Kingdom Phylum (plural Phyla) Class Order Family Genus (plura genera) Species Each taxon may have subtaxa

32 LINNAEUS CLASSIFICATION The groupings or taxa from most general to most specific are: Domain Kingdom Phylum (animals) or Division (plants) Class Order Family Did King Philip cried out For Goodness sakes? Genus Species

33 HUMANS Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominidae Genus Homo Species sapien

34 PHYLOGENY & CLADISTICS Phylogeny The whole evolutionary history of a species or other taxonomic group. At the base of the tree is the oldest ancestor Forks in branches represent divergences of new species The top of the tree represents the most recent time, so from the base to the top of a branch is a progression through time. Cladistics A classification scheme based on phylogeny and the idea that any one group of related organisms was derived from a common ancestor

35 PHYLOGENETIC TREES Cladogram A diagram similar to a phylogenetic tree that does not take into account the time of a divergence.

36 PHYLOGENETIC TREE OF LIFE

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38 DICHOTOMOUS KEYS A tool used by biologists to identify unknown organisms Consists of a series of paired comparisons of characteristics used to sort organisms into smaller and smaller groups

39 Dichotomous Keys Using Smiley Faces Instructions: Use the key below to identify the species name of each of the smileys below. 1. Teeth visible...go to 2 6. Smiling, happy face... Smilus traditionalis...teeth not visible...go to 4...Not happy, frowning or other...go to 7 2. Has a wide, toothy smile...smilus toothyus 7. Mouth curved down, frowning... Smilus saddus...is not smiling...go to 3... Mouth is a small circle...smilus suprisus 3. Visibly crying...smilus dramaticus 8. Has a pirate eye patch...smilus piratus... Frowning...Smilus upsettus...does not have eye patch... go to 9 4. Eyes are symmetrical... go to 5 9. One eye is much larger than the other eye... Smilus mutatus...eyes not symmetrical...go to 8 One eye is winking...smilus winkus 5. Eyes shaped like hearts... Smilus valentinus...eyes are shaped as ovals...go to 6

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41 Genus: Aliens

42 Be sure to use Genus & Species name Be sure to use proper formatting rules for writing scientific names!!

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45 H. Precede the description with the part that is being described (leaves are red. Instead of leaves present) I. Start the choices in a couplet with the same word, if possible. J. Start each couplet with different words, if possible.

46 Assignment #4