Lecture 7- Animal Diversity III Flashcards
Deuterostomia Group Phyla
Echinodermata + Chordata
Deuterostomia- Shared Derived Characteristics
- Radial, indeterminate cleavage
- Coelom forms from archenteron
- Blastopore becomes anus
- Other organisms do this (convergent evolution)
Phylum Echinodermata and shared derived trait
Deuterostomia
“Spiny skin”
Sea stars, sea urchins, sand dollars, sea cucumbers
- Larva- bilateral symmetry
- Adults- often 5-part symmetry (still bilateral)
Endoskeleton: Internal, calcium carbonate
Spines project through skin
Shared derived trait: Water Vascular System
- Network of fluid-filled canals
- Feeding, gas exchange
Shared Derived Traits Chordates
- Notochord- solid rod of cartilage on the dorsal side
- Dorsal hollow nerve cord- spinal cord
- Pharyngeal slits
- Post-anal tail
All chordates have these traits AT SOME POINT during their development but do not have to last into adulthood (Embryotically, mammals have all of these things but as adults do not)
Basal Chordates Traits
Invertebrates
Marine suspension feeders
1 Hox cluster
Vertebrates Derived traits
- Segmented vertebrae (instead of notochord)
- Go from having 1 Hox cluster to at least 2 (2 or more)
(More complex body plan)
Gnathostomes Derived traits
(“jaw mouth”)
- Hinged jaw (grasp and hold prey)
- Bony skeleton (replaces cartilage)
- 4 Hox clusters- more complexity
Osteichthyes Derived traits
(“bone fish”- named for bony skeleton)
- Lungs/swim bladder
Lobe-fins Derived traits
Muscular fins/limbs for locomotion
Tetrapods Derived traits
(Amphibians, moving to land)
- 4 limbs with digits (fingers and toes)
- Neck
- Fused pelvic girdle (efficiently transmits forces through body needed for living on land)
Amniotes Derived traits
- Amniotic egg
- Rib cage ventilation
(completely adapted for land, amniotic egg prevents desiccation and rib cage ventilation rather than through skin)
Mammals Derived Traits (Phyla within Amniotes)
- Mammary glands
- Give birth to live young
- Hair, fat layer under skin to retain heat
Traits of Monotremes
Mammals
- Lay eggs
- Have hair, produce milk, but no nipples
- Platypus and echidnas
Traits of Marsupials
Mammals
- Give birth to live young
- Have nipples
- Placenta: structure for nutrient exchange from mother to embryo
- Born very early, complete development while nursing
- Often in pouch (koalas, opossums, kangaroos)
Traits of Eutherians
Mammals
- Also called “placental mammals”- have complex placenta
- Longer pregnancy than marsupials
- Complete embryonic development in uterus
