Evolution Notes Week 3
Evolution Notes Week 3 Anth 314
Popular in Human Evolution
Popular in anthropology, evolution, sphr
verified elite notetaker
This 1 page Class Notes was uploaded by jewellog on Friday October 9, 2015. The Class Notes belongs to Anth 314 at James Madison University taught by Dr. Harlacker in Fall 2015. Since its upload, it has received 12 views. For similar materials see Human Evolution in anthropology, evolution, sphr at James Madison University.
Reviews for Evolution Notes Week 3
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/09/15
quotGrades of Adaptationquot Tuesday September 15 2015 1358 Systematics Prosimians What about evolutionary Systematics Phonetics morphological traits Cladistics focusing on the recency of common ancestors looking at the overall adaptive picture Grades vs Clades o Pongid Grade Orangs gorillas chimps o Hominidae clade gorillas chimps humans In Linneaen taxonomy both groups are in the family level Evolutionary systematics as a classification approach will sometimes come up with results that are cladisitcal or phonetic The cladistic approach is becoming more common And Evolutionary systematical expression of animal relationships 0 The line towards humans is longer to show how much more we have diverged Terminology A Clade is a group that has ALL animals that descended from a particular animal and none that did NOT evolve from that particular animal A sister taxongroup is the next closest relative one branching point backwards We always say that any one individual in a clade is more closely related to each other than they are to their sister groups Sister groups are generally part of a different taxon this is the general expectation Gibbons Always make sure to specify which group you are working with But how do we go about building classifications How do we determine evolutionary relationships among our taxa Traits We are looking for homology Homology traits are sharedsimilar because of common ancestry 0 Present in at least two taxa and their last common ancestor o The forelimb in very early vertebrates possessed by birds dolphins and human arms this means tha when quadrupeds became a thing this was the basic plot for the forelimb this was modified for different animals but the structure is the same which can help us understand the relationships between vertebrates Homoplasy Analogy there are traits that can be similar not because of inheritance but because of other maybe environmental factors 0 This is not seen in the LCA of the animals that share this trait 0 Sometimes similar environmental stressors create similar solutions 0 Such is the case for bat wings and fly wings Cladistics Identifying homologies and using those to sort species into categories Willi Hennig was the founder of Cladistics All you show on a cladogram is the branching order for a group of animals second OUtgroup SiSter Group Ingroup Group species based on recency of common ancestor F G D E A B c You can put in a whole bunch of data in to a program and it will divide a cladogram for each species it gets Cladograms do not depict the levels of variation simply order of divergence Monophyletic Clade one ancestral group and all of its decendents Paraphyletic Group a group that is either composed of part of a clade or takes in parts of multiple clades o This comes up a lot when we talk about primates or early hominid fossils o A lot of our older groupings are paraphyletic Homology We have to use homologies to find common ancestors and clades Plesiomorphies ancestral states that occur in all members of a particular clade of interest consistent through all of these organisms they don39t help to differentiate taxa within that larger group like body hair 0 Symplesiomorphies shared all ancestral states are shared by definition Apomorphies these are the useful ones derived states occur in only some of the members of a particular clade of interest like dietary specialization O Synapomorphies shared useful for determining relationships within a clade of interest no tail 0 Autapomorphies unique not helpful in determining relationships among taxa bipedalism These traits relate to each part of a taxa differently o Brow ridge ancestral with respect to other hominoids but derived with respect to other non homonoid primates o Fingernails ancestral with respect to other primates derived with respect to other mammals Polarity which end is the ancestral end 0 A good way to figure this out is to look at the outgroup and how they express the trait and that is frequently the ancestral form of the trait Classifying from the ground up Is a trait discrete present absent expressed in a number of discrete states for a small number of categories Continuous trait is anything that can be measured but they are more difficult for cladistic analysis to work with Generally we also want to choose out outgroup which is one that should be significantly different from the outgroup All cladograms that a program spits out are a hypothesis anthropoinds NW Monkeys OW Monkeys Apes Humans Lorises Lemurs Tarsiers Branch lnternode ancestral species Root Common ancestor Ancestral trait Derived trait Human Evolution Page 1
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'