Evolution cladogram

Evolution cladogram Learn how and when to remove this template message A cladogram is the diagrammatic result of an analysis, which groups taxa on the basis of synapomorphies alone.

Then, give teams one or two days to prepare their sheets for building the cladogram. It might also be useful to show students where there are still a few major gaps in the fossil record.

States shared between the outgroup and some members of the in-group are symplesiomorphies; states that are present only in a subset of the in-group are synapomorphies.

On "Cladogram Day", Evolution cladogram class will finish your classroom cladogram. Since this lesson has not yet been thoroughly classroom tested, if you give it a good try, please give us any feedback you can: See the Illustration Resources page.

This is simply a trick of presentation, but represents no meaning in terms of relatedness. Algorithms for cladograms or other types of phylogenetic trees include least squaresneighbor-joiningparsimonymaximum likelihoodand Bayesian inference.

How do you make a tree. Use a smaller scale, and have each class' cladogram posted on a different part of the wall see other scales at the end of the Time Machine lesson on this site.

On "Cladogram Day", your class will finish your classroom cladogram. If necessary, input from other classmates can be used. The second gap runs for 30 my in the late Triassic myaand the most recent consists of a very spotty fossil record for about 12 my of the Oligocene period mya.

In the following cladogram, which groups are most closely related.

Evolution: Synapomorphies & Cladogram

Try our Patterns in Time lesson, where students develop a more realistic understanding of deep time, along with the realization that the different vertabrate classes emerged separately over several s of millions of years, and did not exist prior to their emergence as revealed in the fossil record.

For instance, mammary glands are a shared characteristic of mammals. Likewise, a tongue to gather nectar is a trait derived by various groups of moths, butterflies, bees, and some flies.

Sometimes divergent evolution occurs in rapid succession, or simultaneously, amoung a number of populations. Enhance and clarify as needed with the intended concepts in mind. Just pull out and display the appropriate one for the current class.

Symplesiomorphies, by contrast, are characters that all organisms in the cladogram have.

Diagraming Evolution, or How to read a Cladogram

Evolution cladogram Convergent evolution Some measures attempt to measure the amount of homoplasy in a dataset with reference to a tree, [18] though it is not necessarily clear precisely what property these measures aim to quantify [19] Consistency index[ edit ] The consistency index CI measures the consistency of a tree to a set of data — a measure of the minimum amount of homoplasy implied by the tree.

Download and print out all 5 sections of that document some 37 pages. Statistics[ edit ] Incongruence length difference test or partition homogeneity test [ edit ] The incongruence length difference test ILD is a measurement Evolution cladogram how the combination of different datasets e.

A set of 13 big sheets with large print can be found at end of this lesson in PDF format. If a bird, bat, and a winged insect were scored for the character, "presence of wings", a homoplasy would be introduced into the dataset, and this could potentially confound the analysis, possibly resulting in a false hypothesis of relationships.

In both diagrams, A and B share a node that is further away from the origin of the line in the diagram. There are NO amphibian fossils found that pre-date the earliest fishes, NO reptile fossils which pre-date the earliest amphibians, and NO mammal fossils which pre-date the earliest reptile fossils.

Find some large panels, one for each class get some refrigerator packing boxes, or equivalent, open them upand place a reduced-scale cladogram on each carton. Various modifications to vertebrate limbs and their uses. Unless DNA or fossil evidence show otherwise, it should be assumed that the wings originated ancestrally, and that all the groups have since adapted their wings.

Biologists sometimes use the term parsimony for a specific kind of cladogram generation algorithm and sometimes as an umbrella term for all phylogenetic algorithms. Students prepare the components for building a Colossal Classroom Cladogram of vertebrate evolution, then put it together, showing the gradual, mosaic accumulation.

Biologists use cladograms and phylogenetic trees to illustrate relationships among organisms and evolutionary relationships for organisms with a shared common ancestor. Evolutionary trees depict clades. A clade is a group of organisms that includes an ancestor and all descendants of that ancestor.

You can think of a clade as a branch on the tree of life. Some examples of clades are shown on the tree below. Evolution: Synapomorphies & Cladogram Divergent and Convergent Pathways Once a new species forms, its evolutionary pathway may diverge from the original species.

29 Responses to Diagraming Evolution, or How to read a Cladogram Nick 8 December, at am # As a Ecology, Behavior and Evolution Major in the Bio dept at UCSD I do love a good cladogram.

Evolutionary trees depict clades. A clade is a group of organisms that includes an ancestor and all descendants of that ancestor. You can think of a clade as a branch on the tree of life. Some examples of clades are shown on the tree below.

Evolution cladogram
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Lesson: evolution: Classroom Cladogram of Vertebrate/Human Evolution