Deuterostomes part 3

Question 1

amniotes

Answer 1

• monophyletic clade within the tetrapod clade

- no larval stage (direct development)

Question 2

key adaptations to live a fully terrestrial life..

Answer 2

• amniotic egg

- tough,dry skin

Question 3

amniotic egg

Answer 3

• embryo surrounded by 4 tissue membranes
• covered by a shell that slows water loss, but allows gas exchange
• amniote embryos develop in a self contained aqueous environment
• can be fully terrestrial

Question 4

amniotic egg have 4 extraembryonic membranes

Answer 4

• amniotic protects embryo from sudden movement
• yolk sac encloses nutrients for developing embryo
• chorion and allantois changes gas exchange and excretion of wastes

Question 5

tough, dry skin

Answer 5

• skin cells filled with keratin, lipids- mostly impermeable to water
• decreased vulnerability of dehydration/ desiccation

Question 6

reptilian synapomorphy

Answer 6

-outer layer of skin forms scales or feathers made of keratin

Question 7

function of feathers/scales

Answer 7

• to reduce desiccation
• to protect against abrasion
• in locomotion in some

Question 8

reptiles

Answer 8

• all reptiles have internal fertilization
• most deposit amniotic egg on land (oviparous)
• females retains eggs, gives birth to juveniles (ovoviviparous)

Question 9

thermoregulation

Answer 9

• reptiles are ectothermic
• cant regulate body temperature
• maintain body temperature by absorbing heat from the environment
  
  • behavioral thermoregulation

Question 10

extinct groups of reptiles in both marine and terrestrial habitats

Answer 10

• plesiosaurs: marine predators
• pterosaurs: flying predators
• parareptiles: large herbivores
• Ichthyosaurs: marine predators

Question 11

three clades of extant reptiles

Answer 11

• turtles
• archosaurs
• lepidosaurs

Question 12

turtles

Answer 12

• inhabit freshwater, marine and terrestrial habitats
• all lay eggs on land
• body plan changed little in 200 my
  
  • bony, box like shell
• shell of dorsal and ventral plates fused to vertebrae (dorsally) and ribs (ventrally)

Question 13

Lepidosaurs

Answer 13

• tuatarans
• squamates
  
  • snakes and lizards

Question 14

tuatarans

Answer 14

• lizard like in appearance
• only 2 extant species
• both found only on islands off the coast of New Zealand

Question 15

Squamates

Answer 15

• snakes and lizards
• both have overlapping scales that protect against desiccation and abrasion
  
  • scales are a reptilian synapomorphy

Question 16

lizards

Answer 16

• most with limbs, some legless species
• most are small
• mostly insectivores, some herbivores, some larger predators such as the komodo dragon

Question 17

snakes

Answer 17

• limbless squamates (some with vestigial limbs)
• streamlined body for efficient burrowing, climbing, swimming
• all carnivorous, some with toxin glands that immobilize, kill, partially digest prey, many others are constrictors

Question 18

Archosaurs

Answer 18

-crocodilians and birds

Question 19

relationship between crocodiles and birds

Answer 19

• gene sequences
• circulation and respiration
  
  • both have 4 chambered heart, unidirectional air flow through lungs
• degreee of parental care

Question 20

crocodilians

Answer 20

• 20 species including crocodiles, alligators, caimans
• all semi aquatic, but lay eggs on land, or in floating piles of vegetation
• all pare predatory archosaurs

Question 21

dinosaurs

Answer 21

• very diverse groups of archosaurs

- carnivores and herbivores, quadrupeds and bipeds,tiny and enormous

Question 22

therapod dinosaurs

Answer 22

• all bipedal, with 3 fingered feet and hands

- some therapods made feather like structures out of keratin

Question 23

archaeopteryx

Answer 23

• an extinct bird like therapod dinosaur

- fossils show traits of both feathered dinosaurs and birds

Question 24

therapods that are still alive

Answer 24

• birds!
• only surviving clades of dinosaurs
• all have feathers, provide substantial insulation, used for locomotion, camouflage, and in courtship displays
• feathers also increase surface area to forelimbs, generate lift for flight

Question 25

features of birds important for flight

Answer 25

• hollow bones, with internal struts
  
  • reduces weight, while maintaining strength
• sternum forms broad surface area for pectoral (flight) muscles to attach
• furcula (wishbone) strengthens the thoraic skeleton
• flight metabolically expensive and bird lungs are complex in forms
  
  • air pumped through lungs unidirectional (not in and out)
    - maximize input of oxygen

Question 26

birds lack teeth

Answer 26

• teeth lost over evolutionary time
• inferred from presence of teeth in other archosaurs
• birds eat a diversity of plants/ animals including seeds, fruits, insects, other vertebrates, and carrion

Question 27

paleognaths

Answer 27

• flightless or weak flying birds

- emu, kiwis, ostrich, cassowary

Question 28

neognaths

Answer 28

much more diverse clade, which includes the rest of the living birds

Question 29

synapsid

Answer 29

one distinct opening in skull behind the eye