Week 10: Phylogenetics 2 - Application

Question 1

what are the 3 small bones all mammals have in the middle ear

Answer 1

ossicles:

the malleus (hammer)
incus (anvil)
stapes (stirrup)

These bones play a crucial role in the process of hearing.

Question 2

How do ossicles work to process sound

Answer 2

The sound waves enter the ear canal and hit the eardrum, causing it to vibrate.

The vibrations are then transmitted through the ossicles, which amplify the sound and transmit it to the inner ear.

Pretty sure this is how in depth she wants us to know about this topic

Question 3

what did mammals evolved from?

Answer 3

tetrapods (four-feet)

particularly a clade called the synapsids.

Question 4

how do we know that synapsids are our ancestors

Answer 4

because their skulls fit together in the same way ours do, and no other lineages have this.

Question 5

were the ossicles once part of the jaw in synapsids?

Answer 5

yes

Question 6

did the the Monotremes & Therians/Eutherians evolved the middle ear independently

Answer 6

yes

check page 11

Question 7

Are monotreme and therian ear bones an example of convergent evolution?

Answer 7

yes

ossicles evolved independently in different lineages due to a common selection pressure – this is the same mechanism (cause) that we see in convergent evolution.

Question 8

Feathers had many uses before flight. Such as possibly…

Answer 8

Feathers were probably used to signal for mating displays

And nesting

Question 9

A rule of natural selection:

Answer 9

every transitional trait must be beneficial in order to increase in frequency (how common it is) and continue to undergo selection.