Classification

Classification and taxonomy  Define the terms taxonomy, phylogeny and classification  Explain the relationship between classification and phylogeny  Outline the features of the five kingdoms

Make a glossary for the following key terms  Biological classification  Taxonomy  Phylogeny  Monophyletic  Common ancestor  Evolutionary distance  Species  Domain

Why Classify?

  A non-profit organization dedicated to the complete inventory of all species of life on Earth within the next 25 years.   Aims to describe and classify all of the surviving species of the world (there are about 13.6 million species)

Why Classify?  Convenience  Make studying living organisms more manageable  Make it easier to identify organisms – both new and old  To help us to see interspecies relationships  To create a world wide record of all living organisms  To help communication

Five Kingdom System PlantaeFungiAnimalia Protoctista Prokaryotae Eukaryotic cells Multicellular Eukaryotic cells Unicellular Prokaryotes

Characteristics of the 5 Kingdoms   Prokaryote e.g. bacteria and cyanobacteria No nucleus, no nuclear membrane, no membrane- bound organelles, have a loop of DNA but no chromosomes, smaller ribosomes and a mesosome  Protoctista e.g. seaweed, algae Eukaryotic,single and multi cellular, plant like or animal like, heterotrophic or autotrophic Eukaryotic,single and multi cellular, plant like or animal like, heterotrophic or autotrophic  Fungi e.g. yeast, mushrooms Not able to photosynthesise, cells walls made of chitin, bodies composed of a mycelium of hyphae, multinucleated, most are saprobiontic, some are parasitic

Characteristics of the 5 Kingdoms   Plants Eukaryotic, multicellular, have chlorophyll, PS - photoautotrophs, cellulose cell wall, primitive plants make spores, advanced plants make seeds, produce multicellular embryos from fertilised eggs  Animals Eukaryotic, multicellular, heterotrophic, have nervous system, able to move, growth occurs throughout body, fertilised eggs develop into a blastula

Hierarchical System Kingdom : largest group of organisms sharing common features Phylum : major subdivision of a kingdom Class: group of related orders, subdivision of a phylum Order: group of related families, subdivision of a class Family : group of closely related genera, subdivision of order Genus: group of related species, subdivision of family Species: breed freely with one another

K – P – C – O – F – G - S King Philip Conquered Over France, Germany and Spain Or King Philip Called Out For Good Soup!

The higher the taxa the more diversity is shown between individuals within a group i.e. there is more variation between organisms in the kingdom animalae than between organisms in the class mammalia

What is a species?

Species  the smallest basic taxonomic unit used to define living organisms  A group of individuals –with similar key features but show variation –They are usually able to interbreed and produce fertile offspring BUT: this definition does not take into account simple organisms that reproduce asexually

Ligers?!  Hobbs (male) from Sierra Safari Zoo  Hobbs, with a mane like a lion, the long body of a tiger, and more mass than either, is a striking animal.  He exhibits traits of both parents, his mother was a Bengal tigress and his father an African lion.  He roars like a lion and swims like a tiger.

 Breeding a male donkey to a female horse results in a mule  Breeding a male horse to a female donkey produces a hinny.

Carl Linnaeus Founder of the binomial system of nomenclature and the hierarchical system of classification in the early 18 th century

Binomial nomenclature  Conventions in writing scientific names –Made up of genus and species name –Genus name starts with a capital letter –Species name all in small letters –If writing by hand: underline –If typing: use italics

Humans!  K = animalia  P = chordata  C = mammalia  O = primates  F = hominidae  G= homo  S = sapiens Homo sapiens

Binomial nomenclature of wild flowers Common name Scientific name Red clover Trifolium pratense Herb robert Geranium robertianum Cut-leaved cranesbill Geranium dissectum Meadow thistle Cirsium dissectum 1.In addition to writing the name in italics, what other convention is used for scientific names? 2.What genus does red clover belong to? 3.What is the species name of meadow thistle? 4.Which two plants are most closely related: a)Meadow thistle and cut-leaved cranesbill b)Herb robert and cut-leaved cranesbill?

Dichotomous key  Method used to identify and name specimens.  Series of yes/no questions that eventually lead you to the name of the specimen.  Should have one question less than the number of species it will identify.

How is biochemistry used to look at evolutionary relationships?  Proteins  DNA  Use p to help you understand this

The table shows the percentage difference between the coding DNA of humans, chimpanzees, gorillas and orangutans 1. Which two animals appear to be most closely related? 2. Which two are most distantly related? 3. Explain why these data cannot provide us with firm guidelines about whether humans and chimpanzees should be placed in the same genus. % difference in DNA Humans and chimpanzees 0.87 Humans and gorillas 1.04 Humans and orangutans 2.18 Chimpanzees and gorillas 0.99 Chimpanzees and orangutans 2.14 Gorillas and orangutans 2.25

Answers 1. Humans and chimpanzees 2. Gorillas and orangutans

Answer to Q3  There is no clear definition of what a genus is and what criteria should be used for placing different species in the same genus.  If we do use DNA sequences in this way, then there is no agreement about whether it is more valid to look at every part of the DNA in a species or whether we should concentrate on particular areas, such as just the regions that code for protein (as was done here).  We can also question whether sheer numbers of differences in DNA bases can justifiably be used to determine classification, or whether we should take into account their effects as well.

The Three Domains?  How has Woese’s 3 domain system of classification changed the original hierarchical system?  Discuss whether the five-kingdom and the three-domain classifications are completely different from one another, or if they could possibly be used together. (p209)

Answer  The three domains are the highest taxa.  It is possible to have the domain Eukarya, with the kingdoms Protoctista, Fungi, Plantae and Animalia as subdivisions of it.  However, we cannot keep the kingdom Prokaryota, as that is now split at a higher level.

Work for Easter  Explain the meaning of the terms classification and phylogeny using p of your text books.