canine bio

What is a cladogram?

a diagram that shows evolutionary relationships among group of organisms based on traits

build it

Which organism evolved first? Which organism evolved last? How many nodes are on this cladogram? Which organisms have fur?

Tortise

House cat

4

horse, wolf, leopard, house cat

What is a phylogenetic tree?

A diagram that shows ancestors in a group of organisms based on shared DNA

What is the relationship between DNA sequences and a phylogenetic tree?

More DNA shared = closer together on diagram because more closely related and branched off from other species more recently

Look at the phylogenetic tree to the right. Identify the organism that shares the most recent common ancestor with the lemur. Justify your answer.

Tarsier shares most recent common ancestor with the lemur

because they are closest together

and on same branch

If a species is closely related to another species, will they be closer or further apart on the phylogenetic tree? Why?

Closer together →more DNA in common and split more recently from other organisims

Examine the DNA sequences above for the species A-D. Which two species will be the closest on a phylogenetic tree? How do you know?

B + C will be closest together because they have the least amount of differences in their DNA sequence

Examine the DNA sequences above for species A-D. Which two species will be the furthest apart on a phylogenetic tree? How do you know?

A + D will be the farthest apart because they have the most uncommon DNA

What is artificial selection? How do humans play a role in artificial selection?

The process where humans pick traits and breed organisms specifically to get those traits →driven entirely by humans

What is the purpose of selective breeding?

To promote desirable traits in organisms over generations though controlled breeding

You are a German Shepard dog breeder. You would like to have German shepherds that are bigger and stronger. How could you make this happen?

Take the biggest/strongest in the generation + breed them together. Repeat over several generations until it becomes the most common trait

Explain the difference between inbreeding and outbreeding

inbreeding: mating of related individuals

out breeding: mating of unrelated individuals

Explain how inbreeding practices can lead to increases in certain genetic diseases

because individuals are closely related, there are fewer gene options avable.

If a genetic disorder is present the chances of indivudals inheriting it increases due to the smaller gene pool.

Speciation is the formation of new and distinct species in the course of evolution. How do we know if speciation occured?

reproductive isolation → the species can no longer reproduce and make viable, fertile offsprings.

What are the 3 types of reproductive isolation that can lead to speciation?

Geopraphic isolation → physically seperated

Behavioral isolation → mating behaviors are too different

Temporal isolation →timing doesn’t match (mating season, active times, etc.)

A flood moved a raft of amazon rats away from their original population. There’s enough distance that the groups will never meet in nature again. What type of reproductive isolation is this?

Geographic isolation

Pink tulips open in the morning, while Lavender tulips open in the afternoon. The bees that pollinate these tulips can’t carry pollen between the types of tulips because of their flowers being closed at different times of day. What type of reproductive isolation is this?

Temporal isolation

Certain species of crickets will only mate with males that produce a particular mating song. What type of reproductive isolation is this?

Behavioral isolation