Lecture 2

Question 1

What is a cladogram?

Answer 1

way of showing the relationships between different groups (taxa)

Question 2

What is a sister taxon?

Answer 2

The closest relatives of a taxonomic group

Question 3

What is the sister group to placental mammals?

Answer 3

Marsupials

Question 4

What is a monophyletic group?

Answer 4

includes an ancestor and all their descendants (clade)

Question 5

True or false: Characteristics shared by all extant members of a clade were likely present in their common ancestor

Answer 5

True

Question 6

What is a paraphyletic group?

Answer 6

includes an ancestor and some their descendants

Question 7

What is a polyphyletic group?

Answer 7

includes two or more descendants but not their ancestor

Question 8

What is a clade?

Answer 8

a group that includes a common ancestor and all of its descendants (monophyletic group)

Question 9

What is a Linnean Taxonomy?

Answer 9

a rank-based ordering system of clades

Question 10

True or false: Clades are a fact

Answer 10

False. Clades are a hypothesis

Question 11

What group do chordates belong to?

Answer 11

Deuterostomes

Question 12

What is our sister group within the animals?

Answer 12

Echinoderms

Question 13

What is the oldest recognized Chordate in the fossil record?

Answer 13

Pikaia gracilens

Question 14

How do we decide which species belongs to a clade?

Answer 14

Comparative method: Philosophy

Question 15

What are common or defining traits of a clade?

Answer 15

A characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants

Question 16

How do lancelets feed?

Answer 16

Filter feed - bury themselves in the ground

Question 17

what are the 5 chordate synapomorphies?

Answer 17

1. Notochord
2. Dorsal hollow nerve cord
3. Pharyngeal slits
4. Postanal tails
5. An endostyle (cephalochordates & urochordates) or thyroid (vertebrates) gland (homologous)

Question 18

Describe the notochord

Answer 18

The notochord is a flexible rod that forms during embryogenesis in all chordates

Question 19

What is a synapomorphic trait?

Answer 19

does not need to be expressed at every stage of development

Question 20

What are the three fates of the notochord?

Answer 20

1. Cephalochordates: retain a notochord into adulthood
   - Primary axial structure that supports their body
2. Urochordates: have a notochord as larvae but lose it during metamorphosis into adulthood
3. Vertebrates: the vertebral column forms around the notochord during embryogenesis
   - Species vary in how much of the notochord they retain

Question 21

How do lamprey feed?

Answer 21

They use their specialized teeth to latch onto and parasitize other larger vertebrates

Question 22

Trait distinguishing agathas

Answer 22

No jaw

Question 23

How do hagfish feed?

Answer 23

burrow into and eat the carcasses of dead animals on the bottom of the ocean

Question 24

3 reasons why hagfish are hard to classify:

Answer 24

Hagfish are a ghost lineage, hard to find, highly specialized

Question 25

What species are included in cyclostomes?

Answer 25

Hagfish and lamprey

Question 26

Gnathostomata distinguishing characteristic

Answer 26

Jaw

Question 27

Chondrichthyes distinguishing characteristic

Answer 27

Cartilaginous fish

Question 28

Osteichthyes distinguishing characteristic

Answer 28

Boney fish

Question 29

Actinopterigii distinguishing characteristic

Answer 29

Rays, fins

Question 30

Sarcoptereygii distinguishing characteristic

Answer 30

Fleshy fins

Question 31

Lazarus taxa definition

Answer 31

Extant species or taxa that were once thought to be extinct.

Question 32

What type of breathing do dipnoi do?

Answer 32

bi-modal breathing (they can breathe water (with gills) and air (with lungs))

Question 33

What clade do all modern amphibians belong to?

Answer 33

Lissamphibia

Question 34

where must reproduction of Lissamphibia occur?

Answer 34

Lissamphibia must reproduce in or near water

Question 35

How are amniotes characterized (2)?

Answer 35

by specialized membranes that protect their embryos from water loss, only vertebrates that can live fully terrestrial lives

Question 36

The four mammalian synapomorphies

Answer 36

Synapsid skull, Hair, Mammary glands, 3 inner are bones

Question 37

Monotremes distinguishing characteristic (2)

Answer 37

lay eggs, offspring hatch at very immature stage then nurse

Question 38

Marsupials distinguishing characteristics (4)

Answer 38

give birth to live young, simple placenta, offspring finish developing in pouch where they nurse, short gestation

Question 39

Eutherian mammals distinguishing characteristic (4)

Answer 39

Well developed placenta, give birth to live young, long gestation, brown adipose tissue

Question 40

What did the plate tectonics theory predict?

Answer 40

early on in mammalian evolution a small group of mammals were stranded in Africa when that continent was isolated from the others

Question 41

what is the only extant subclass of the clade Dinosauria?

Answer 41

the Aves

Question 42

What animal is the only member of their clade (helps understand Sauropsid evolution)

Answer 42

Tuatara

Question 43

What is the anapsid origin hypothesis?

Answer 43

most sauropods have a Diapsid skull, extant turtles lack temporal fenestrae

Question 44

Has the Anapsid Origin Hypothesis been refuted and why?

Answer 44

Yes - turtle fossils show that (like sauropods), they once had a diapsid skull have since then lost that trait