Chapter 29 Flashcards
2 types of Deuterostomes
1) Echinoderms
2) Chordates
Phylum Echinoderms
Adults - Pentaradial Symmetry
Larval - Bilateral Symmetry
- Capable of Regeneration
- Water Vascular System
- Nerve Ring
Phylum Chordata
5 TRAITS:
1) Notochord
2) Dorsal Hollow Nerve Cord
3) Pharyngeal Gill Slits
4) Post Anal Tail
5) Endostyle/ Thyroid Gland
5 Classes of Echinodermata
Asteroidea: Sea Stars
Ophiuroidea: Brittle Stars
Echinoidea: Sea urchins, sand dollars
Crinoidea: Sea Lilies
Holothuroidea: Sea cucumbers
What is a madreporite
The enterance to the water vascular system
What is unique to echinoderms?
Their water vascular system: a network of hydraulic canals branching into tube feet that help with feeding and movement
Adult echinoderms have ______ symmetry, while larval have _______ symmetry
Radial (usually multiples of 5), Bilateral
Secondarily pentaradial
Regeneration
A form of asexual reproduction that is a type of fission called autotomy (casting off a part of the body)
How do Echinoderms move and grip surfaces?
Using their tube feet, which grip substrate using adhesive chemicals
Asteroidea
Sea Stars and Sea Daisies
Sea Stars feed on bivalves, have tube feet, have multiple arms radiating from a central disk
Ophiuroidea
Brittle Stars
Have a unique central disk, some are predators and scavengers while other are suspension feeders, have tube feet
Echinoidea
Sea urchins and sand dollars
Have no arms but have five rows of tube feet. Sea urchins have muscles that can pivot their spines (which have toxins in them)
Crinoidea
Sea Lillies and Feather Stars
Both are suspension/filtration feeders, look like plants but aren’t!!
Holothuroidea
Sea Cucumbers
Lack a spine, have a reduced endoskeleton, and don’t look much like other echinoderms
What is the special relationship holothuroidea have?
They have a commensalistic relationship with a certain type of fish. The fish hides in it’s GI tract. The fish gets nutrition and the sea cucumber gets nothing 🧍♀️🗿
3 subphylum’s of chordata
1) Urochordata (tunicates/sea squirts)
2) Cephalochordata (lancelet)
3) Vertebrata
Urochordata
Tunicates
Covered in tunicin, larvae resembles tadpoles (they have more chordate characteristic than the adults)
Cephalochordata
Lancelets
Small filter feeders, bury in substrate
General Order of Evolution
1) Cyanobacteria, fungi, and protists
2) small plants and fungi
3) first animals
4) tall plants
5) Tiktaalik
6) first amniotes
7) first reptiles
What are Myxini and Peteromyzontida
Sister taxa
What is the outgroup of deuterostomes
Echinodermata
What are Reptilia and Mammalia
Sister taxa
What is an endostyle?
A longitudinal ciliated groove on the ventral wall of the pharynx, which produces mucus to gather food particles
What happens to the endostyle in larval lampreys?
It metamorphoses into the thyroid gland in adults. It is homologous to the thyroid gland in vertebrates
What does the thyroid gland do?
Controls hormones of metabolism (thyroxin)
What are tetrapods?
Vertebrates with limbs
(Amphibia, Reptilia, mammals)
What is a notochord?
a longitudinal flexible rod between the digestive tube and nerve cord
What does the notochord become in higher vertebrates?
The intervertebral disks
What does the dorsal hollow nerve cord develop into?
The central nervous system: the brain and spinal cord
What are pharyngeal gill slits?
Pharyngeal clefts develop into slits that open to outside the body
Function in…
1) feeding
2) gas exchange
3) mucus production
What do pharyngeal gill slits turn into?
They develop into parts of the ear, head, neck, and jaw in TETRAPODS
What is a post anal tail used for?
Motion, defense, burrowing, and courtship rituals
What is unique about tunicates?
They are highly derived and have fewer HOX genes than other vertebrates (9 HOX genes instead of at least 13) !!!
Homeobox genes
A DNA sequence (part of a gene) that’s 180 base pairs long. Found within genes that are involved in the regulation of patterns of embryological development
PAX genes
Paired Box genes that code for TISSUE SPECIFIC transcription factors. Pax proteins are important for earth animal development for the specification of specific tissues
- turns totipotent and undifferentiated cells into differentiated!
HOX vs PAX genes
HOX: Codes for segments and parts
PAX: Tells tissues what to become