Phylogenies and Cladograms

Phylogenies and Cladograms

By Stacy King

Multiple Choice

The largest level of classification that divides organisms as either eukaryotes, eubacteria or achaebacteria

• Domain
• Kingdom
• Phylogeny
• Taxonomy

Multiple Choice

This is the system scientists use to help classify organisms

• taxonomy

• taxidermy

• income tax

• taxation

Multiple Choice

Are archaea multicellular or unicellular?

• Multicellular

• Unicellular

Multiple Choice

Which domain has organisms that live in harsh environments?

• Bacteria

• Archaea

• Both

Animals Diversity

Animals are classified into at least 30 groups called "phyla". Nine of these phyla contain most of the animals that exist on Earth today.

Multiple Choice

Phylogenetics is all about discovering... 

• which organisms are more closely related to each other
• which organisms have more adaptations
• adaptationswhere organisms live in the world
• which organisms are most fit for their environment

Phylogeny

A phylogeny is a branching diagram that shows evolutionary relationships between species. 

Scientists usually determine these relationships based on DNA evidence.

Multiple Choice

Two organisms that are closely related would have

• very similar DNA sequence
• exactly the same DNA sequences
• no proteins in common
• completely different DNA sequence

Cladogram

A cladogram is similar to a phylogeny, but it shows hypothesized relationships between species based on shared physical traits.

For this class, we will treat phylogenies and cladograms as essentially the same.

Multiple Choice

hypothesized relationships between species based on shared physical traits.

• phylogeny

• taxonomy

• cladogram

• pictogram

Phylogenies

You read a phylogeny much like you read a family tree. 

The root of the tree represents the ancestral lineage, and the tips of the branches represent the descendants of that ancestor.

As you move from the root to the tips, you are moving forward in time.

Phylogenies

Recall that traits are passed down from generation to generation. 

As species evolve and traits are inherited, their evolutionary paths may split.

When one lineage splits into two, a new species may arise. We call that 'speciation'. 

Multiple Choice

When one lineage splits into two, a new species may arise. This is referred to as

• speciation

• organism

• taxonomy

• phylum

Phylogenies

Phylogenies trace patterns of shared ancestry between lineages. 

Each lineage has a part of its history that is unique to it alone and parts that are shared with other lineages.​

Phylogenies

Similarly, each lineage has ancestors that are unique to that lineage and ancestors that are shared with other lineages (common ancestors).

Shared lineage = common ancestry!

Multiple Choice

Species 3 is a common ancestor of which species?

• Species C only

• Species D only

• Species A and B

• Species C and D

Multiple Choice

In evolutionary terms, which species is the oldest on the phylogenetic tree?

• Species 1

• Species 2

• Species 3

• Species D

Multiple Choice

Which species is most related to Species D?

• Species A

• Species B

• Species C

• Species 1

Multiple Choice

Which species is most related to Species A?

• Species B

• Species C

• Species D

• B,C, and D are all equally related to A.

Multiple Choice

Species 2 is a common ancestor of which species?

• Species B only

• Species B and C

• Species B, C, and D

• Species A, B, C, and D

Phylogenies

A clade is a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor. 

Imagine clipping a single branch off the phylogeny — all of the organisms on that clipped branch make up a clade.

Multiple Choice

Which species belong in the clade for fur and mammary glands?

• Gorilla only

• Rat and gorilla

• Lizard, alligator, robin, rat, and gorilla

• Hagfish, salmon, and frog

Multiple Choice

Which species belong in the clade for claws or nails?

• Gorilla only

• Rat and gorilla

• Lizard, alligator, robin, rat, and gorilla

• Hagfish, salmon, and frog

Multiple Choice

What feature is unique to the alligator and robin?

• Feathers

• Eggs with shells

• Keratinous scales

• Claws or nails

Multiple Choice

Who is the only species that does NOT have a jaw?

• Hagfish

• Lizard

• Gorilla

• Salmon

Different styles of phylogeny / cladogram

Each of these show the same relationships between species. It is the branching pattern that is important, so the shape can vary.

Cladograms

Cladograms use physical features to distinguish the evolutionary relationships between species.

Each branch represents a different lineage.

Each new feature (vertebrae, bony skeleton, etc) applies only to the species HIGHER UP in the tree.

Multiple Choice

diagram that uses physical features to distinguish the evolutionary relationships between species

• cladogram

• genetics

• phylogeny

• pictogram

Cladograms

If you trace a species lineage from top to base, it includes all the features on the line.

So the rodents & rabbits have hair, amniotic eggs, four limbs, bony skeletons, and vertebrae.

Multiple Choice

What feature separates the sharks and fish from everyone else?

• Vertebrae

• Bony skeleton

• Four limbs

• Eggs with shells

Multiple Choice

What derived feature is unique to the bird and crocodile?

• Vertebrae

• Bony skeleton

• Four limbs

• Eggs with shells

Multiple Choice

What derived feature do all these organisms share?

• Vertebrae

• Bony skeleton

• Four limbs

• Eggs with shells

Multiple Choice

What features does the amphibian have?

• Vertebrae

• Vertebrae and bony skeleton

• Vertebrae, bony skeleton, and four limbs

• Vertebrae, bony skeleton, four limbs, and amniotic egg