Do lab manual for PHYLOGENY

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Phylogeny

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Outline:

Introduction to Phylogeny

Lab Explanation

Lab Time!!

You’re going to look at the changes in organisms through time, in the image here the Top of the tree is today

http://elephant.elehost.com/About_Elephants/Stories/Evolution/ancestry.gif

Phylogeny:

The evolutionary development and diversification of a species, or group of organisms, or of a particular feature (characteristic) of an organism

All organisms can be classified

Phylogeny is the evolutionary development and diversification of a species

This allows us to classify and identify all organisms

All organisms are connected by the passage of genes along the branches of the phylogenetic Tree of Life

http://tolweb.org/tree/learn/concepts/ConceptsImg/LeavesAndAncestors.jpg

Classification:

Classification of organisms = Taxonomy

There are three main Domains:

Bacteria

Archaea

Eukaryotes

Which two are the most similar?

The classification of organisms is called taxonomy

It is based on distinguishing characteristics

There are 3 Domains, Bacteria, Archaea, and Eukaryotes, which we belong to.

Which two seem to be the most similar?

Carl Linnaeus:

Developed modern taxonomical system

Hierarchical system of classification

General

Specific

KEEP

POND

CLEAN

FROGGY

GETS

SICK

So who came up with all of this?

Carl Linnaeus, developed the hierarchical system of classification

It goes: Domain, Kingdom, Phylum, Subphylum, Class, Order, Family, Genus, Species

It starts with the most commonly shared characteristics to species specific characteristics

And can be remembered by the following rhymes, my favorite is

Keep Pond Clean Or Froggy Gets Sick

http://www.icr.org/i/articles/af/linnaeus_found_wide.jpg

http://savannahthecell.weebly.com/uploads/1/3/4/0/13403173/443151711.jpg

Now coming back to the three Dominans, which two are most closely related based on their genetics?

Here you can see looking at the tree of life, based on their genetics, the Archaea are more closely related to the Eukaryotes.

Taxonomy of Art:

Kingdom

Phylum

Class

Order

Family

Genus

species

But you’re not going to look at genetics in class today, instead you will be looking at physical characteristics to classify different organisms and then specifically with fish.

I’m going to start off with something that will hopefully be more relatable to you, looking at the a classification of music.

So we start in the Domain of Art, within art there are three kingdoms…

Phylogenetic Tree:

Taxonomic classifications reflect phylogeny

Phylogeny  Evolutionary History of Organism

Species with similar characteristics have a common ancestor

Greater resemblance, more recent divergence

This classification system reflects the evolutionary history of an organism, which is phylogeny.

Taxonomy and Phylogeny are very closely related.

Each species can be traced back to a common ancestor based on shared characteristics

This is commonly expressed as a phylogenetic tree

The phylogenetic trees you will be working with today will be based on phenotypic characteristics, in other words how an organism looks

Phylogeny of Music:

Male

Female

Solo

American

R&B

Pop

One Direction

Beyonce

Adele

Aretha Franklin

Usher

Stevie Wonder

TLC

So looking at the taxonomy of music as a phylogenetic tree, we start at the bottom, with the most broad characteristic, pop music.

Phylogenetic Tree – Example

So now taking that same tree and looking at the phylogeny of vertebrates.

The most broad characteristic is that they are all vertebrates and getting more specific

Reading the tree: A vertebrate that has a bony skeleton with four limbs, and lacks an amniotic egg, would be amphibians

The tree is made to show the relationships between organisms. Key point is the visual identification of “how closely related” the “new” characteristic is shown through the tree. These traits are the new adaptions.

Evolutionary Relationships:

Convergent evolution

Does NOT share a common ancestor

Shared traits based on environmental factors

Divergent evolution

Shares a common ancestor

Trait variation over time

Now we’ll look at different ways in which physical characteristics are derived.

There are two types of evolutionary relationships:

And there is convergent evolution, where species may appear similar, but these traits evolved due to similar environments not because of a common ancestor

So here we have a falcon and a bat, which look similar, but the falcon is the descendent of an ancestral bird and the bat is the decedent of an ancestral mammal.

This is why genetics are now used to determine the placement of an organism on the tree.

Divergent evolution which is represented by the horizontal lines of the phylogenetic tree and this type shares a common ancestor.

Divergent Evolution – Speciation:

Allopatric Speciation- a population splits into two geographically isolated populations

Sympatric Speciation- the formation of two or more descendant species from a single ancestral species all occupying the same geographic location

There are two main factors in divergent evolution

Allopatric speciation; where a population splits into two isolated populations as a result these populations can no longer interbreed

And Sympatric speciation; where two or more descendent species share the same geographic location and are more closely related

And thus these populations can interbreed

Darwin’s Finches:

Charles Darwin traveled to the Galapagos Islands and studied the speciation of local finches

The ancestral finch was a ground-dwelling, seed-eating finch

After the burst of speciation in the Galapagos, a total of 14 species would exist:

3 species of ground-dwelling seed-eaters;

3 others living on cacti and eating seeds;

1 living in trees and eating seeds;

7 species of tree-dwelling insect-eaters.

The most well known study of speciation and evolution was done by Darwin who studied the speciation of finches in the Galapagos Islands

Through this study Darwin found the two major types of speciation present on the islands

He found there was an ancestral finch that was a ground dwelling, seed-eating finch.

As speciation occurred over time, a total of 14 species would exist and they would have varying characteristics

Darwin’s Finches:

Common Ancestor

Here is a breakdown of the 14 species that Darwin found on the islands and how they relate to each other

So there was a common ancestor, then speciation occurred and some evolved to eat seed, fruit, and insects; this changed the shape of the birds beak through time based on the food consumed. This is something to think about during the lab today, how does the environment pressure trait selection?

Green beetles have been selected against, and brown beetles have flourished.

Changes in a population of beetles over time:

Another way trait selection occurs is through adaptation and fitness, here you can see that these birds are picking out the green beetles, and over time the green beetles may become extinct because the pressure of not becoming food, selects for the brown color adaptation. So over time the beetle population changes from green and brown variations, to only brown beetles.

http://evolution.berkeley.edu/admin/media/3/52571_evo_resources_resource_image_380_original.gif

Fitness – the ability to survive and reproduce

Adaptation – any characteristic that increases fitness

For the beetles in the picture, what characteristic was an adaptation that increased fitness?

Color – brown beetles were more fit and were able to survive longer

So to reiterate An adaptation is any characteristic that increases fitness, which is defined as the ability to survive and reproduce.

Keep fitness in mind today too as you complete the lab.

http://evolution.berkeley.edu/admin/media/3/52571_evo_resources_resource_image_380_original.gif

Today’s Lab:

Part I:

Work as a group to divide the animals in the bag at your table into 4-5 groups

Identify what characteristics you used to make these divisions and complete the worksheet

Part II - Fish Phylogeny:

Work as a group to create a phylogenetic tree using: pictures of fish, guides at your table, white board, and markers

Be sure to label the “speciation” (what characteristic you chose to separate them by) for each branch!

There’s two parts to today’s lab, the first part should take around 30 minutes, and the second part will take the remainder of the time.

Next Week- our last class!

Due:

Phylogeny lab

Final lab report

SEE GUIDELINES ON BLACKBOARD

“Lab Report Instructions” under “Lab Report” tab

In class:

Quiz IV

Video & discussion