Deuterostomes

Question 1

what are the shared derived characteristics in the deuterostome clade?

Answer 1

• radial, indeterminate cleavage
• coelom from archentron
• blastospore -> anus

Question 2

describe Phylum Echinodermata

Answer 2

• “spiny skins”
• sea stars, sea urchins, sea cucumbers, sand dollar
• often 5-part symmetry
• endoskeleton (internal CaCO3)

Question 3

what is the SDT for Echinodermata?

Answer 3

Water Vascular System

• network of fluid-filled canals
• feeding, gas exchange, movement

Question 4

SDTs for Phylum Chordata

Answer 4

1. Notochord
2. Dorsal, hallow nerve cord
3. Post-anal tail
4. Pharyngeal slit/cleft

Question 5

Basal Chordate (s)

Answer 5

Lancelet (Cephalochordate) and Tunicates (Urochordates)

• invertebrates
• marine suspension feeders
• 1 Hox cluster

Question 6

what are the SDTs for Vertebrates

Answer 6

• bone or cartilage vertebrate that replaced notochord
• 2 + Hox clusters (result of complete genome duplication and increased genetic complexity - > more complex body plan)
• chordate character more evident in embryo

Question 7

Basal Vertebrate (s)

Answer 7

Jawless Fish

• hagfish, lamprey
• cartilage

Question 8

Gnathostome characteristic

Answer 8

Jaw-mouth

Question 9

SDTs for Gnathostome

Answer 9

• hinged jaw
• bony skeleton
• 4 Hox Clusters - more complexity (from another genome duplication)

Question 10

Basal Gnathostome (s)

Answer 10

Chondricthyes - cartilaginous fish (bone only in teeth and fin tails)

• ancestor had bone all over body
• DERIVED TRAIT of LOSING most bone

Question 11

describe Osteichthyes

Answer 11

“bone fish”

named for ancestral bony skeleton - Calcium Phosphate

Question 12

DT for Osteichthyes

Answer 12

Swim bladder (homologous with lungs)

Question 13

Basal Osteichthyes

Answer 13

Actinoptyergii - ray-finned fish

Question 14

SDTs for Lobe-Fins

Answer 14

Muscular fins/limbs for locomotion (includes all terrestrial vertebrates)

Question 15

Basal Lobe-Fins

Answer 15

Actinisitia - coelcanths

Dipnoi - lungfish (lungs and gills)

Question 16

SDTs for Tetrapods

Answer 16

• 4 limbs with digits
• neck
• fused pelvic girdle (efficiently transmits forces through body) [there’s no buoyancy on land!]

Question 17

Basal Tetrapods

Answer 17

Amphibia

Terrestrial, but require moist environment

• eggs laid in water
• aquatic larva
• thin, moist skin

Ex. frogs, toads, salamanders

Question 18

SDTs for Amniotes

Answer 18

• amniotic egg (amnion: membrane that forms fluid-filled sac around embryo) [allows for completely terrestrial life]
• ribcage ventilation (more efficient than through skin)

Question 19

Reptilia

Answer 19

Phylum Amniotes, Sister Taxon to Mammals

• turtles, lizards, snakes, alligators
• shelled eggs laid on land

Question 20

DTs of Mammals

Answer 20

• mammary glands
• give birth to live young (mostly)
• hair, fat layer under skin -> retain heat

Question 21

what are the three groups of Mammals?

Answer 21

1. monotremes
2. marsupials
3. eutharians

Question 22

monotremes

Answer 22

Basal Animals

• lay eggs
• have hair
• produce milk, but no nipples

Platypus echidnas - only in Australia and New Guinea

Question 23

marsupials

Answer 23

• give birth to live young
• have nipples
• born very early (complete their development while nursing, often in pouch)
• Placenta: structure for nutrient exchange from mother to embryo

Oppossums, Kangaroos, Koalas

Question 24

Eutharians

Answer 24

• “placental mammals” - have complex placenta
• longer pregnancy than marsupials
• complete their embryonic development in uterus

Question 25

DTs of Primates

Answer 25

• large brain, short jaws
• grasping hands/feet
• forward facing eyes
• high parental care
• complex social behavior
• monkeys, apes - fully opposable thumbs

contain lemurs, tarsiers, monkeys, apes

Primates Love Getting Free Hot Coffee and Frapps!

Question 26

what is the relation of humans and chimps?

Answer 26

we did not evolve from chimps. we share a recent CA with them

Question 27

Hominin

Answer 27

• species on human “side” of human-chimp divergence 6-7 mya
• all originated in Africa
• Homo sapiens is only extant hominin, but many extinct species

Question 28

What are the ancestral Hominins?

Answer 28

Australopiths

~4 mya
-fully upright posture

Question 29

Genus Homo

Answer 29

• appeared ~2.4 mya
• Homo erectus (~1.8 mya) - 1st out of Africa
• Homo neanderthalensis (~500-28kya) - Europe and Asia, descended from 2nd migration out of Africa
• Homo sapiens, only extant species

Question 30

Modern Humans - Homo Sapiens characterisitics

Answer 30

• ~2-300 kya, central Africa
• bigger brains (almost 1.5L)
• complex tools
• fully bipedal traits
• small jaw, “short” digestive system
• language and symbolic thought

Question 31

Human Migration

Answer 31

• Eastern Central Africa -> everywhere else- “Out of Africa”

- 3rd “Out of Africa” migration - interbred with other hominins