Lecture 8 Classification of Living Organisms PDF

Classification of Organisms  Homology Learning outcomes: 1. Be able to define the term classification phylogeny, systematics and taxonomy. 2. Understand why and how living organisms are classified. 3. Be able to explain the reason for the classification of organi...

Classification of Organisms  Homology Learning outcomes: 1. Be able to define the term classification phylogeny, systematics and taxonomy. 2. Understand why and how living organisms are classified. 3. Be able to explain the reason for the classification of organisms into 3 Domains. 4. Be able to list the hierarchical system of ranking of organisms. ↓ 5. Understand the binomial system of naming organisms. 6. Be able to list the main distinguishing features of the 6 kingdoms in relation to cell type, cell structure, number of cells and nutrition. 7. Be able to briefly explain how viruses are classified. 8. Be able to list the main characteristics used to classify organisms into kingdoms - 9. Be able to define phylogenetics and have a basic understanding of phylogenetic trees and cladograms 10. Have an understanding of how homologies can be used to trace ancestry. 11. Be able to build a simple phylogenetic tree/cladogram from genetic sequence information. or Terminology & Classification is the process by which scientists group living organisms Organisms are classified based on how similar (characteristics) they are to each other. spenspacies 9) geney mos -5514 Taxonomy: The scientific discipline of naming and classifying organisms Scientists also want to know which groups of organisms are more closely or distantly related to other groups organisms 160515 560-s ‫…يجري التحميل‬ Phylogeny: The study of the evolution of a genetically related group of organisms - distinguished from the development of the individual organism -25 as Systematics is the science of classifying organisms (classification) and determining their patterns of descent (phylogeny). Which ancestors gave rise to - budine - which descendants in &/ · santegers -160 : /1 NNizP , Systematics uses fossils, molecules and genes to infer evolutionary relationships are j i and construct a comprehensive tree of life (showing their evolutionary history/phylogeny) Biologists who study taxonomy are called Taxonomists - Why Classification? = As living things are constantly being investigated, new attributes -= are revealed that affect how organisms are placed in a standard classification system. · Helps us keep track of all the different forms of life and forms a common communication about different groups of living things! Lizard Helps us to determine which creatures are more closely related or more distantly related. gen in J 1605 , =a & Imply evolutionary relationship (= phylogeny) Australian legless lizard snake (top). A snake (bottom)! Illustration purposes!  People wanted to organize their world so they began grouping, or classifying everything they saw E.g. Organisms that; How – Break down dead materials – Reproduce sexually did ‫…يجري التحميل‬ – Are single-celled it – Have cell walls start? – Eat other organisms – Have a nucleus – Are multicellular  The 7 characteristics of Living Things (Living or not??). Movement – Animals move to find food and keep away from predators, plants move to face the light. Reproduction – the ability to produce offspring to keep the species in existence E1 > 9. Sensitivity – responding and reacting to the environment. Growth – Growing larger & stronger adult size. Respiration – Turning food into energy. Excretion – Getting rid of waste. Nutrition – Animals need food for respiration, plants need minerals from the soil  Why classify? To help us see; Relationships, Similarities and Differences To help us organize all the organisms we discover To give every species a name based on a standard method so scientists from different countries can talk about the same animal without confusion  Classification: Naming organisms : Binomial nomenclature /log/ A Swedish botanist/physician named Carl Linnaeus (1707 – 1778) adopted a system of naming organisms called Binomial nomenclature and based on how closely or distantly related they were, he put them into groups –Taxonomic Ranks. Linnaeus is often known as “The Father of Taxonomy”. A two name system for writing scientific names. S 1. Genus name – written first and the first letter always capitalised. 2. Species epithet – written second and the first letter is never capitalised. Epithet: an adjective or phrase describing a quality regarded as characteristic of the S organism. Ganes Sekies Example: Humans arejo · Homo sapiens. - (Genus Homo=man, sapiens-thinking. Literally, in Latin, thinking man). Wbos Both words MUST BE italicised if typed, or underlined separately as follows; E.g.: Streptococcus pneumoniae. Hoping Streptococcus pneumoniae. Staphylococcus pheumonia  is , Taxonomic Hierarchy Introduction https://www.youtube.com/watch?v=kKwOlAqQoLk  Linnaean The Seven Level System taxonomy a HOW TO REMEMBER! m =6) - Domain mos Did & Kingdom Katy · Phylum L Perry & Class inclusive Come more NP Order J Over ↑ y Family For S Genus Species ↳ Good Soup &, The Seven Level System mmm ‫…يجري التحميل‬ Domain CLASSIFICATION: Ranking of organisms. Putting organisms into a level (a taxon) in a taxonomic hierarchy. verb DOMAINS pro.. All life on earth is classified into three domains. 1. Eukarya, 2. Archaea, Si 3. Bacteria (Eubacteria). ↳ Succes F X Si : The Domain rank in classification is the most inclusive. IJdaj & The 3 domains are believed to have evolved from a lineage of living organisms that arose around 3.5 million years ago. The 3 Domains share the same genetic code, use the same amino acids to build proteins, have similar biochemical pathways and so on. Evidence of common descent. - JX ji18/ -. Bacteria are believed to have evolved first, followed by Archaea and later the first Eukaryotes. Domains t · ea Domains are the broadest taxonomic classification > - Thermophiles- > in high temprature of living organisms eacidophilesinacidicconditi as oftheir energy metabolism. Methanogens - produce methane as a by product > - > > - psychrophiles in cold - tempreture about Alkali philes very high put > - in - > extremophile > - - live in extremes environments. > - piezophile > - live in high pressure condition. -Xerophile > - blooms at temprature of 176. > - Mesophiles -> at moderate tempoeture. Divides cellular life forms into 3 Domains: 15. – Archaea- very primitive forms of bacteria – Bacteria - more advanced forms of bacteria – Eukarya -all life forms with eukaryotic cells Domains s Archaea and Bacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles) Eukarya are more complex and have a nucleus and membrane-bound organelles Three domains O · Learn these Know the taxonomic classification of humans Domain 1. Domain Kingdom 2. Kingdom Watch this video! https://www.youtube.com/watch? Phylum 3. phylm v=KLMn4XwS8Tw Class 4. class Order 5. Order Family 6. family Genus 7. Genes Species 8. Species- Bewise put impor Main characteristics used to classify organisms into kingdoms tr sent ↑ & - - ⑭ Memorize preduce their food that eats other organism that own Anto troph > - can Heterotrophe : organism using light , #20/C02 or other chemical plants or animals for energy of. natrients. 3 Autotrointo trophs 3 chemo auto trophs Compare and contrast the classification of these living things Y · https://www.youtube.com/wa tch?v=vqxomJIBGcY Backbone Define the following: Chordata: Carnivora:  Classification of viruses Viruses are classified based on; 1. Morphology, / - 2 San - "Ecological niche (bacterial viruses do not infect eukaryotes and visa versa), 2. -. · i · - 3. Host, 4. Mode of replication of their genetic material, Virusus 5. Type of disease they cause, 6. Genetic relatedness. I st Downing Viral classification starts at the level of order and continues as follows, i. Order ii. Family iii. Subfamily · iv. Genus v. Species. How many species are there on earth? (5-100million species estimate) Recent report predicts 8.7 million eukaryotic species (self directed study – check this figure?) About 1.8 million species have been named - nearly 2/3 of these are insects /X To organise life we use a the tree of life to represent evolutionary relationships. Diagram illustration  1501 %15 s Phylogeny and the tree of life Evidence from morphological, biochemical, and gene sequence data suggests that all organisms on Earth are genetically related, and living things can be represented by a vast evolutionary tree, The Tree of Life. /401 & The Tree of Life represents the phylogeny (evolutionary history) of organisms. Phylogeny is the evolutionary history of a species or group of species. % Phylogeny implies that different species arise from previous forms via Si descent, and that all organisms, from the smallest microbe to the largest plants L and vertebrates are related. / The more recently two species converge as you go down the tree of life, the more recent the common ancestor and the more closely related those species are. (fx(4/ As we continue down the tree, species become less and less related.  * Phylogeny and the tree of life Diagrams for illustration important T L http://media.hhmi.org/biointeractive/click/Phylogenetic_Trees/03.html Creating Phylogenetic Trees from DNA Sequences Illustration - looking at a portion of the phylogenetic tree y The more recently two species converge as you go down the tree of life, the more recent the common ancestor and the more closely related those species are. As one continues down the tree, species become less and less related.  5s Trace a path from the tip of our branch to the root. Every organism on earth will converge with our path at some point whether very recent or very distant. This means that every living thing is related in some way.  - To see how related two species are we can use homologies A. Anatomical homologyb B. DNA homology PNAs) " Homology refers to similarity between characteristics in different species of organisms. 5I 8951) #.. ( O Sinai Anatomical similarity and evolutionary relationships Homologous structures (similar structures) Anatomical features, of different organisms, j that have a similar appearance or function because they were inherited from a common ancestor that also had them are called homologies. Xavissos E.g. the forelimb of a bear, the wing of a bird, and your arm have the same functional types of bones as did our shared reptilian il ancestor. Therefore, these bones are homologous structures. The more homologies two organisms possess, the more likely it is that they have a close genetic relationship. sai Stones  - Analogous structures Anatomical features that have the same form or function in different ---- species that have no known common ancestor. Examples: the wings of a bird and a butterfly are analogous -90 structures because they are superficially similar in shape and function. Both of these very distinct species lines solved the problem of getting off of the ground in essentially the same way. However, their wings are quite different on the inside.  S Self Directed Study https://www.youtube.com/watch?v=KLMn4XwS8Tw2018 The tree of life – review Name two species within the genus Homo that are now extinct? Homo Homo habilis erectus ‫…يجري التحميل‬ Homo heidelbergensis https://media.hhmi.org/biointeractive/click/Phylogenetic_Trees/02.html One common type of mutation that can be used to track common ancestry is the single nucleotide polymorphism (SNP). A SNP is a change of one DNA base pair - S into another. Define SNPs Changlouei ~ D ↑ & Define Indels ↳ wh cut o Another useful class of DNA mutations for tracing relatedness are insertions and deletions, or “Indels” for short. These are mutations in which one or more nucleotide pairs in a DNA strand is lost or gained.  Modern Taxonomy & The Evidence used to classify into groups j1 1) Embryology 2) Chromosomes / DNA 3) Biochemistry 4) Physiology SinssI D 5) Evolution 590- 6) Behaviour J DNA Similarity and Evolutionary Relationships 1s More distantly related species have had more time elapse since they shared a common ancestor; therefore, they have had more time for mutations (errors) to accumulate in their DNA Closely related species have had little time to accumulate mutations since their last common ancestor, so their DNA sequences are much more similar. Comparing genetic sequences allow scientists to determine if organisms are closely or distantly related. Diagrams for illustration NOTE: Before you can compare sequences, you need to make sure that you are comparing  & 160515758 Phylogenetic trees : Systematists depict evolutionary relationships in branching phylogenetic trees A phylogenetic tree is a diagram that describes evolutionary history by showing how ancestors are related to their descendants and how much those descendants have changed over time. gasps The tips represent groups of descendent taxa (species A,B,C,D and E below left). The internal nodes represent the common ancestor of those descendants. & The tips are the present (the descendants) and the internal nodes the past (ancestors). The edge length in some trees corresponds to time estimates or percentage similarity. The root of the tree represents the ancestral lineage. A single branch point from which all branches originate. The node closest to the root of the tree represents the most recent common ancestor for all organisms in the tree. Each branch point (also called an internal node) represents a divergence event (speciation), or splitting apart of a single group into two descendant groups. Know the names of the different types of phytogenic trees Illustration purposes only Phylogenetics and phylogenetic trees A phylogenetic tree is a diagram that represents evolutionary relationships among organisms. For example organisms A, B, C, D and E below. The pattern of branching in a phylogenetic tree reflects how species evolved from a series of common ancestors. Two species are more related if they have a more recent common ancestor and less related if they have a less recent common ancestor. Phylogenetics and phylogenetic trees At each branch point lies the most recent common ancestor of all the groups descended from that branch point. Example: At the branch point giving rise to species A and B, we find the most recent common ancestor of A and B. At the branch point right above the root of the tree, we find the most recent common ancestor of (A, B, C, D, E). The diagram below shows how each species in the tree can trace its ancestry back to the most recent common ancestor at the branch point above the root: Each horizontal line represents a series of ancestors, leading up to the species at its end. Sister taxa are groups that share an immediate common ancestor. A rooted tree includes a branch to represent the last common ancestor of all taxa in the tree A basal taxon diverges early in the history of a group and originates near the common ancestor of the group. A polytomy is a branch from which more than two groups emerge. Diagrams for illustration  purposes Application of phylogenetic trees 1. To determine who is more closely related to who? Suppose that we wanted to say whether A and B or B and C are more closely related. Follow the lines of both pairs of species backward in the tree. Since A and B converge at a common ancestor first as we move backwards, and B only converges with C after its junction point with A, we can say that A and B are more related than B and C. We can't say whether A and B are more closely related than C and D. Because the horizontal axis of this tree doesn't represent time in a direct way. Applying Phylogenies 2. A phylogeny was used to identify the species of whale from which “whale meat” originated. Legal to harvest Minke whales caught in S. Hemisphere but NOT Minke, Humpback or Fin Whales in N. Hemisphere. DNA sequence analysis showed that the 6 unknown samples (found in Japanese markets) were most closely related to whales that are not legal to harvest. Phylogenetics and phylogenetic trees Tracing the ancestry of the domesticated dog 1. Trace back it’s lineage to a node which has another branch coming off it. 2. The grey wolf is the most closely related organism to the domesticated dog. This doesn’t mean that the domesticated dog descended from the grey wolf but that these two came from a common ancestor. Phylogenetic tree understand it When did these two share a common ancestor with the grey fox They evolved along separate branches a long time ago >10 million years ago Comparing genetic sequences and building a cladogram/phylogram. Comparing genetic sequences and building a cladogram Comparing genetic sequences and building a cladogram DNA sequence similarity http://www.barcodinglife.org/index.php/SDP_Home