Campbell Biology Tenth Edition Chapter 26 Lecture PDF

CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 26 Phylogeny and the Tree of Lif...

CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 26 Phylogeny and the Tree of Life Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick 1 © 2014 Pearson Education, Inc. Get out your note cards! ▪ Use your resources to create note cards for the following terms/ideas: 1. Convergent Evolution 2. Clade 3. Homologous 4. Analogous 5. Synapomorphy ▪ You may want to write in pencil and leave yourself some room so you can add/subtract later 2 © 2014 Pearson Education, Inc. Recap ▪ The theory of evolution was developed by Charles Darwin and is better when called The Theory of Evolution by Natural Selection ▪ Theories like Darwin’s are proven time and time again, so the term theory is not synonymous with words like “hunch” or “guess” ▪ Darwin’s work (and every other legitimate scientist’s) follows The Scientific Method 3 © 2014 Pearson Education, Inc.  The Scientific Method ▪ Starts with an observation, is followed by research, and begins with the formation of a hypothesis A Proper Hypothesis is: ▪ Phrased as a statement ▪ Testable / Falsifiable ▪ Said to be “accepted” or “rejected” at the end of the experiment ▪ The ”best” type of experiment is a controlled experiment, where only one variable is tested against a “control” which is unchanged ▪ Data collected is either qualitative or quantitative 4 © 2014 Pearson Education, Inc. Phylogenies show evolutionary relationships ▪ Taxonomy is the scientific discipline concerned with classifying and naming organisms ▪ Carolus Linnaeus established our system of taxonomy based on resemblances between species ▪ Two key features of his system: two-part names for species and hierarchical classification 5 © 2014 Pearson Education, Inc.  ▪ The two-part scientific name of a species is called a binomial ▪ The first part of the name is the genus ▪ The second part is unique for each species within the genus ▪ For example; Homo sapiens ▪ The first letter of the genus is capitalized, and the entire species name is italicized ▪ Both parts together name the species 6 © 2014 Pearson Education, Inc. Hierarchical Classification ▪ The taxonomic groups from broad to narrow are domain, kingdom, phylum, class, order, family, genus, and species ▪ A taxonomic unit at any level of hierarchy is called a taxon (plural = taxa) ▪ The broader taxa are not comparable between lineages ▪ For example, an order of snails has less genetic diversity than an order of mammals 7 © 2014 Pearson Education, Inc. Learning Objectives in Chapter 26 1. Understand how phylogenies show evolutionary relationships 2. Be able to construct a phylogenetic tree 8 © 2014 Pearson Education, Inc. Figure 26.3 Cell division error Species: Panthera pardus Genus: Panthera Family: Felidae Order: Carnivora Class: Mammalia Phylum: Chordata Domain: Kingdom: Bacteria Animalia Domain: Archaea Domain: Eukarya 9 © 2014 Pearson Education, Inc. Figure 26.4 Order Family Genus Species Panthera Felidae Panthera pardus (leopard) Taxidea Carnivora Taxidea Mustelidae taxus (American badger) Lutra Lutra lutra (European 1 otter) Canis latrans Canidae Canis 2 (coyote) Canis lupus (gray wolf) 10 © 2014 Pearson Education, Inc. Concept 1: The connection between phylogenies and evolutionary relationships 11 © 2014 Pearson Education, Inc. Linking Classification and Phylogeny ▪ The evolutionary history of a group of organisms can be represented in a branching phylogenetic tree ▪ The phylogenetic tree is a diagrammatic representation of evolutionary history of the shown group of organisms 12 © 2014 Pearson Education, Inc.  ▪ Phylogeny is the evolutionary history of a species or group of related species and results from both process and pattern ▪ The processes of evolution (natural selection and other mechanisms that change genetic composition of populations) ▪ The patterns of the products that evolution has formed over time ▪ For example, phylogeny shows that legless lizards and snakes evolved from different lineages of legged lizards 13 © 2014 Pearson Education, Inc.  ▪ The discipline of systematics classifies organisms and determines their evolutionary relationships ▪ We use these classifications to build phylogenetic trees Geckos ANCESTRAL No limbs LIZARD Snakes (with limbs) Iguanas Monitor lizard Eastern glass lizard No limbs 14 ©Figure 26.2:Education, 2014 Pearson Phylogenetic Inc. tree showing convergent evolution of limbless bodies  ▪ Each branch point on the phylogenetic tree represents the divergence of two species from a common ancestor ▪ “Common Ancestor” is sometimes abbreviated C.A. ▪ Sister taxa are groups that share an immediate common ancestor ▪ These are sisters to each other and “cousins” to the other taxa from that common ancestor 15 © 2014 Pearson Education, Inc. Figure 26.5 Branch point: where lineages diverge Taxon A 3 Taxon B Sister 4 taxa Taxon C 2 Taxon D 5 Taxon E ANCESTRAL 1 LINEAGE Taxon F Basal Taxon G taxon This branch point This branch point forms represents the a polytomy: more than two common ancestor of branches emerge from this taxa A–G. point. 16 © 2014 Pearson Education, Inc.  ▪ A rooted tree includes a branch to represent the last common ancestor of all taxa in the tree ▪ Shows the “great grandma” ▪ 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 17 © 2014 Pearson Education, Inc. Figure 26.5 Branch point: where lineages diverge Taxon A 3 Taxon B Sister 4 taxa Taxon C 2 Taxon D 5 Taxon E ANCESTRAL 1 LINEAGE Taxon F Basal Taxon G taxon This branch point This branch point forms represents the a polytomy: more than two common ancestor of branches emerge from this taxa A–G. point. 18 © 2014 Pearson Education, Inc. What We Can and Cannot Learn from Phylogenetic Trees 1. Phylogenetic trees show patterns of descent, not phenotypic similarity 2. Phylogenetic trees do not indicate when species evolved or how much change occurred in a lineage ▪ Trees DO indicate patterns 3. It should not be assumed that a taxon “evolved from” the taxon next to it ▪ They both evolved from a common ancestor 19 © 2014 Pearson Education, Inc. Shared characters are used to construct phylogenetic trees ▪ Once homologous characters have been identified, they can be used to infer a phylogeny 20 © 2014 Pearson Education, Inc. What’s a homologous character? ▪ Character – any observable feature or trait of an organism. Basically: a characteristic. ▪ Example of a character: my dog has brown fur with white spots. ▪ Not a character: My dog’s favorite show is “America’s Got Talent” ▪ Visual and genetic similarities due to shared ancestry are called homologies ▪ Organisms with similar morphologies or DNA sequences are likely to be more closely related than organisms with different structures or sequences 21 © 2014 Pearson Education, Inc. Shared characters are used to construct phylogenetic trees ▪ The opposite of a homology is an analogy ▪ Analogous characters occur when a similarity of function and superficial resemblance of structures in organisms that are not genetically related. 22 © 2014 Pearson Education, Inc. Understanding homology ▪ Convergent evolution occurs when similar environmental pressures and natural selection produce similar adaptations in organisms from different evolutionary lineages 23 © 2014 Pearson Education, Inc. Figure 26.7 - Convergent evolution in burrowers Australian marsupial North American eutherian mole 24 © 2014 Pearson Education, Inc. Concept 2: How to construct phylogenetic trees 25 © 2014 Pearson Education, Inc. Take out something to write on and without working with the person next to you, put the following companies into a “phylogenetic” tree: ▪ Applebees ▪ Tim Hortons ▪ Dunkin’ Donuts ▪ TGI Fridays ▪ McDonalds ▪ Pizza Hut ▪ Burger King ▪ Outback Steakhouse ▪ Taco Bell ▪ Panera Bread ▪ Starbucks ▪ Chipotle ▪ Dominoes ▪ Chiquita bananas 26 © 2014 Pearson Education, Inc. Constructing a Phylogenetic Tree ▪ Cladistics groups organisms by common descent ▪ A clade is a group of species that includes an ancestral species and all its descendants ▪ Clades can be nested in larger clades, but not all groupings of organisms qualify as clades 27 © 2014 Pearson Education, Inc.  ▪ A clade is monophyletic, signifying that it consists of the ancestor species and all its descendants (a) Monophyletic group (clade) (b) Paraphyletic group (c) Polyphyletic group A A A 1 B Group I B B Group I C C C D D 3 D E E Group II E F 2 F F G G G 28 © 2014 Pearson Education, Inc.  ▪ A paraphyletic grouping consists of an ancestral species and some (but not all) of the descendants ▪ “Para-” means “beside” (a) Monophyletic group (clade) (b) Paraphyletic group (c) Polyphyletic group A A A 1 B Group I B B Group III C C C D D 3 D E E Group II E F 2 F F G G G 29 © 2014 Pearson Education, Inc.  ▪ A polyphyletic grouping includes distantly related species but does not include their most recent common ancestor ▪ “Poly-” means “many” ▪ Polyphyletic groups are distinguished from paraphyletic groups by the fact that they do not include the most recent common ancestor (a) Monophyletic group (clade) (b) Paraphyletic group (c) Polyphyletic group A A A 1 B Group I B B Group III C C C D D 3 D E E Group II E F 2 F F 30 © 2014 Pearson Education, Inc. G G G Figure 26.11 Paraphyletic group Common ancestor of even-toed Other even-toed ungulates ungulates Hippopotamuses Cetaceans Seals Bears Other carnivores Polyphyletic group 31 © 2014 Pearson Education, Inc. Constructing a Phylogenetic Tree ▪ In comparison with its ancestor, an organism has both shared and different characteristics ▪ A character can be both ancestral and/or derived, depending on the context ▪ A shared ancestral character is a character that originated in an ancestor of the taxon ▪ A shared derived character is an evolutionary novelty unique to a particular clade ▪ When building a tree, it is useful to know in which clade a shared derived character first appeared 32 © 2014 Pearson Education, Inc. Constructing a Phylogenetic Tree ▪ Synapomorphy – a character shared by all taxa of a group ▪ “Morph-” = “appearance” ▪ Example of synapomorphy: birds have feathers 33 © 2014 Pearson Education, Inc.  Lancelet Lamprey Bass Vertebral column Frog Hinged jaws Turtle Four walking legs Amnion Leopard Hair (b) Phylogenetic tree 34 © 2014 Pearson Figure 26.12bEducation, Inc.  ▪ In some, branch length can represent chronological time, and branching points can be determined from the fossil record Drosophila Lancelet Zebrafish Frog Chicken Human Mouse CENO- PALEOZOIC MESOZOIC ZOIC 542 251 65.5 Present Millions of years ago 35 © 2014 Pearson Figure 26.14 Education, Inc.  ▪ Birds and crocodiles share several features: four-chambered hearts, song, nest building, and brooding ▪ These characteristics likely evolved in a common ancestor and were shared by all of its descendants, including dinosaurs ▪ The fossil record Front limb supports nest Hind limb building and brooding in dinosaurs Eggs (a) Fossil remains of Oviraptor (b) Artist’s reconstruction of the and eggs dinosaur’s posture based on the 36 © 2014 Pearson Education, Inc. fossil findings Figure 26.17 Figure 26.16 Lizards and snakes Crocodilians Ornithischian Common dinosaurs ancestor of crocodilians, dinosaurs, Saurischian and birds dinosaurs Birds 37 © 2014 Pearson Education, Inc. For Next Lecture: 1. Remember to bring notecards to (every) class 2. Do Chapter 26 HW in blackboard 3. Do Chapter 26 Quiz in blackboard 4. Read Ch 26 if needed 38 © 2014 Pearson Education, Inc.