SYSTEMATICS AND PHYLOGENY

Upon first glance, one would probably classify this as a…________, but…

Organizing Life ____________________ is the branch of biology concerned with identifying, naming, and classifying organisms. Remember?... Gray Wolf: ________________-Eukarya, _______________-Animalia, _______________-Chordata, ______________-Mammalia, _______________-Carnivora, _______________-Canidae, _______________-Canus, _______________-lupus What are taxa? Some describe the groups as being “_____________________” because one group exists within another group.

Think of your “global” address Species: Panthera pardus Genus: Panthera Family: Felidae Think of your “global” address Order: Carnivora Class: Mammalia Figure 26.3 Hierarchical classification Phylum: Chordata Kingdom: Animalia Bacteria Domain: Eukarya Archaea

Taxonomy’s Binomial System In the mid-eighteenth century, Carolus Linnaeus developed the binomial system of nomenclature to classify organisms First word is the __________________ The second word is the _______________ ___________________: This refers to one species (of potentially many) within its genus A species is referred to by the full binomial name (Genus + species) Genus name can be used alone to refer to a group of related species What do the Genus and species actually specify?

IMPORTANT-

Why are scientific names needed? Lilium canadense Lilium bulbiferum What is the difference in these fish? -Common names vary both locally and globally -Languages vary -Similar to the need for the metric system of measurements Jellyfish Crawfish Silverfish

–also known as _____________ Classification lists the unique characters of each taxon and is intended to reflect phylogeny, but… _____________ is an analytical branch of biology that relies on ____________________________________________________ to determine evolutionary history and relationships –also known as _____________ Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (All): © Sylvia S. Mader

Deciphering evolutionary history It is often represented as a ___________________________: A diagram indicating lines of descent Each branching point is a divergence from a ______________ ______________ It represents an organism that gives rise to two new groups. It is also called a ________

__________________characters: Two types of characters used to construct a tree are: __________________characters: Present in some members of a group, but absent in the common ancestor These traits “were not seen previously” _________________ characters: Present in all members of a group and present in the common ancestor (ancestral traits) When inferring evolutionary relationships, it is useful to know in which clade a shared derived character first appeared Lancelet Lamprey Tuna Figure 26.5 How to read a phylogenetic tree Salamander Turtle Leopard

Canis lupus Order Family Genus Species ALL THESE SPECIES ARE HERE Felidae Panthera Pantherapardus Taxidea Taxidea taxus Carnivora Mustelidae Lutra lutra Lutra THIS IS THE OF ALL SPECIES PICTURED HERE Figure 26.4 The connection between classification and phylogeny Canis latrans Canidae Canis TAXA Canis lupus

Canis lupus Order Family Genus Species Felidae Panthera Pantherapardus Taxidea Taxidea taxus Carnivora Weakness of basic phylogenetic tree: Mustelidae Lutra lutra Lutra Figure 26.4 The connection between classification and phylogeny Canis latrans Canidae Canis Can’t be sure otter evolved before wolf Canis lupus Also, sister taxa do not mean one came from another!

How do we know that the construction of a phylogenetic tree is the best hypothesis of phylogeny? One way is through ___________________. This is a method that uses shared and derived traits to hypothesize evolutionary history. This will usually consider the simplest solution, __________________________________, in the evolutionary history of your groups of organisms being studied. Species ingroup lancelet (outgroup) chimpanzee crocodile dog finch lizard frog tuna Your groups will be called a _____________________________ and they represent a common ancestor and all of its descendant lineages. Biologists can construct _______________________________ to visually represent the derived characteristics of your clade. mammary glands hair gizzard epidermal scales Traits amniotic egg We’ll always need to select an __________________________: a species from an evolutionary heritage that diverged before the lineage we are studying – called the __________________________________ four limbs vertebrae notochord in embryo

Fig. 19.6 enlarged brain hair, mammary glands chimpanzee Amniotic egg common ancestor hair, mammary glands chimpanzee Amniotic egg long canine teeth terrier feathers gizzard finch four limbs crocodile epidermal scales lizard vertebrae frog common ancestor tuna lancelet (outgroup)

3. A __________________ group includes taxa with different ancestors. 1. A __________ is a _______________ group. It consists of an ancestral species and ALL of its descendants. 3. A __________________ group includes taxa with different ancestors. 2. A ________________ group consists of an ancestral species and some, but not all of its descendants CLADES VS. GROUPS A A A B Group I B B Figure 26.10 Monophyletic, paraphyletic, and polyphyletic groups C C C D D D E E Group II E Group III F F F G G G

CLADE OR NOT? D D D B B B E E E C C C A F A F A F H H H G G G I I I common ancestor

Which species has gone through the most genetic change? In some trees, the length of a branch can reflect the number of genetic changes that have taken place in a particular DNA sequence in that lineage Drosophila Lancelet Zebrafish 542 mya Figure 26.12 Branch lengths can indicate relative amounts of genetic change Frog Which species has gone through the most genetic change? Chicken 251 mya Human Mouse

Percentage differences between sequences Human 30% 40% Mushroom Tulip Percentage differences between sequences Human 30% 40% Mushroom 40% Tulip What is maximum parsimony? What is maximum likelyhood? Comparison of possible trees 15% 5% 5% Figure 26.14 Trees with different likelihoods 15% 15% 10% 20% 25% Tree 1: Tree 2:

Remember that phylogenetic tree are _____________ Remember that phylogenetic tree are _____________. As new information is found, these hypotheses can be _____________ or ________________. The best hypotheses for phylogenetic trees fit the most data: morphological, molecular, and fossil. This has been applied to infer features of dinosaurs from birds like me.

What kind of data allows us to infer phylogenic information? _______________ _________________ Genes or other DNA sequences are also homologous if they are descended from a common ancestor _______________ structures: Bones in the forelimbs of mammals Beware the analogous __________________ evolution results in this

______________: Good, but incomplete ______________: Good, but incomplete. It is often difficult to determine the phylogeny of a fossil. Typically, hard parts are mineralized. Soft tissued organisms tend to decay before they are buried. Watch TED-ed: How to fossilize yourself

Analagous scenarios can also exist in molecular data: Coincidences: Molecular homoplasies

Molecular Data Systematics assumes: Immunological techniques ___________________ Comparisons Systematics assumes: Two species with similar base-pair sequences are assumed to be closely related Two species with differing base-pair sequences are assumed to be only distantly related Mitochondrial DNA (mtDNA) often looked at as well because mutation rate is 10x that of DNA ______________ Comparisons Immunological techniques Degree of cross reaction used to judge relationship Amino acid sequencing Similar sequence in same protein indicates close relationship (cytochrome C) Molecular _____________ We use non-adaptive nucleotide sequence mutations (neutral) Assumed constant rate of mutation over time Fossil record + matching mutation rate = increased strength in hypothesis

Embryology and Development can reveals homologies Both organisms end up developing an anus form from the blastopore. anus Vertebrate (modern bony fish) blastopore Anus develops from blastopore in both Echinoderm (sea star) Similar embryos Adult sea star anus Later the echinoderm becomes radially symmetrical

A Three Domain System Historically, scientists (after Aristotle’s time) grouped organisms into two kingdoms, plants and animals In the late 1800’s a third kingdom, the protists, was added. In 1969, the five kingdom idea was brought forth. Basis for placement into a kingdom:

Tree of Life Showing The Three Domains fungi animals In the 1970’s the idea of domains based on __________became the prominent idea on how to classify organisms plants protists protists heterotrophic bacteria cyanobacteria common ancestor

Three-Domain System Sequencing of rRNA suggests all organisms evolved along three distinct lineages: Domain Bacteria Traits: Domain Archaea Domain Eukarya

How these domains differ from one another