Flashcards in Midterm #2 Deck (63):
What are the defining processes of deuterostome development?
They have radial cleavage, under go enterocoely, Anus forms from blastopore and have regulative development.
Which phyla are deuterostomes?
Echinoderms and chordates
Name 5 characteristics of phylum Echinodermata
1. Have an endo-skeleton. 2. Have a water vascular system. 3. Adults have pent-radial symmetry. 4. Larva have bilateral symmetry. 5. capable of regeneration
Name the common classes of Echinodermata.
1. Asteroidea (sea stars). 2.Ophiuroidea (brittle stars). 3. chinoidea (sea urchins). 4. Holothuroidea (sea cucumbers). 5. crinoidea (feather stars)
What are the three main parts of asteroidea's nervous system?
1. Radial nerve ring in central disk. 2. radial nerve ring in ambulacral groove. 3. Nerve net connects the two
what is a ambulacral groove and what phylum and class have them?
Name characteristics of phylum Echinodermata
1. Have radial cleavage (deterstomes). 2. Anus develops from blastopore. 3. larva are bilateral. 4. adults have pent-radial symmetry. 5. Have a endo-skeleton. 6.Use a water vascular system to move via hydrostatic pressure. 7. Can regenerate body parts.
What are the defining processes of protostome development?
1. Spiral cleavage. 2. Blastopore forms mouth. 3. schizocoely (embryonic development). 4. mosaic development
What does autotomy refer to?
The ability to detach a body part
What are pedicellariae?
Small claspers that are used i cleaning the animals body.
What are 5 defining characteristics of chordates?
1. posses notochord (supports body). 2. Have a DHNC (Dorsal hollow nerve cord. 3. Pharyngeal slits. 4. Postanal tail. 5. Endostyle/throid.
What animals are included in the phylum chordata
Fish, amphibians, reptiles, birds and mammals
What animals are included in the sub-phylum Urochordata?
sea squirts and tunicates (both look like condoms)
is the cardiac stomach investable or the pyloric stomach?
cardiac stomach is invertable, pyloric stomach is not invertable.
What is the feeding process for asterodiea?
mouth--> cardiac stomach (invertable)-->pyloric stomach (not invertable)--->digestive caeca (intestine).
What are the main parts of asteroid's sensory system?
Ocean (sensory tube feet) and eye spots plus sensory cells all over body.
What defines prochordata? and what are the main sub phylums?
they have no skull. Urochordata (sea-squirts) and cephalochordate (laclets)
in chordates what does the notochord do?
supports and stiffens animal and acts as an anchor point for muscle attachment. Allows them to twist and or flex their entire body.
What is the dorsal hollow nerve chord?
the anterior end forms a 3 lobed brain.
What do the pharyngeal slits do?
Connect throat to outside of body and are used for filter feeding. Early vertebrates used them for respiration and in tetrapod they became the ear canal.
What is the postanal tail used for?
What is the endostyle for?
Primative form of thyroid , secretes mucos to trap food also coats pharyngeal slits to be more effective in filter feeding, also releases hormones.
What is the sub phylum urochordata?
What are the characteristics of urochordata?
free swimming larva and sessile adults. Larva have all 5 chordate characteristics, adults only retain pharyngeal slits and end-style.
What is the life cycle of urochordata?
larva attach to sediments lose tail----> lose notochord---> DHNC is reduced (one ganglion)---> reproduction (form gametes)---> new larva.
How does an adult urochordata develop?
pharyngeal slits become a basket for filter feeding. use incurrent and excurrent siphons. endostyle coats pharyngeal basket for more effective feeding.
How does an adult urochordata feed?
water---> incurrent siphons--->pharyngeal basket--->esophagus---> gut---> excurrent siphons----> removes waste and filtered water.
What animals are sin the sub-phylum cephalochordate?
What is significant about cephalochordates?
no gills Diffuse through body tissues, heart, red bloods cells, no brain.
how do cephalochordates feed?
cilia push water down mouth---> filter food (pharyngeal slits)--->cilia move food to intestine---> intracellular digestion. water leaves through atriopore.
How do cephalochordates respire?
Direct diffusion through body wall to tissues.
What 5 notochord characteristics do cephalochordates have?
1. Pharyngeal slits. 2. DHNC. 3. Postanal tail. 4. notochord. 5.endosytle/ thyroid.
What characteristics do larval and adult urochordata have?
Larva have 1) notochord. 2)pharyngeal slits. 3)DHNC. 4) end-style. 5) postnatal tail. Adults only have 1). pharyngeal slits and 2) endostyle.
What are the 4 major evolutionary advantages of early vertebrates?
1) endoskeleton 2) Efficient respiration. 3) Developed brain and sensory structures. 4) paired jaws and limbs.
What is the significance of an endoskeleton in early vertebrates?
1) allows for larger mass because larger muscles can be connected to the stable skeleton. 2) W- shaped muscle tissues gives greater control and strength. 3) Skeleton grows with body.
Why did early vertebrates have more efficient respiration?
pharyngeal slits push water over slits. improved circulation because of gills, heart and muscular blood vessels. This allows for increased metabolism and a predatory life style.
What is asteroid's endoskeleton made up of?
1). Ossicles (calcium carbonate plates)joined with 2) catch collagen. 3) Stereom meshwork that penetrates ossicles.
What made early vertebrate's brain and sensory system more effective
they developed a three lobed brain and paired sensory structures (eyes), pressure receptors (lateral line) and chemical receptors.
Name the two most important developments of an early vertebrate's sensory system.
Neural crest cells helped form part of the skull and echodermal placodes which developed into sensory structures e.g eyes, ears, nose, lateral line.
What are Hox genes?
these are the genes that determine what type of body plan and structures will be developed. E.g like a director decides which scene should happen next. More hox genes means great complexity in body structure.
Name an early vertebrate? and why are they considered to be one?
A Condont because they had early (paired eyes, a notochord, and the first example of bone.
When did early vertebrates first appear?
550 mya ago.
What is the difference between Agnathans and Gnathostomes?
Agnathans are jawless fish and Gnathostomes are jawed fish.
Name 3 Agnathan groups from class.
Ostracoderms( Extinct), Myxini (Hagfish), and Petromyzontida (Lampreys).
Name 6 characteristics of Agnathans
1) weak vertebrae. 2) Notochord. 3) Fiberous and cartilage skeleton. 4) No jaw or paired fins. 5) No scales 6) Poorly developed stomach
What are Myxini and some significant parts of it's lifestyle?
Hagfish, they are parasitic, can go 7 months with out eating, tie themselves into knots for better leverage when working a carcass. Can produced a very very large amount of slime to avoid predation, have 3 hearts,
What are Petromyzontida?
lamprey half of species are parasitic and half do not feed. Reproduction is selective ( large with large and small with small, selecting against average sized).
What is significant about Petromyzontida larva?
lamprey larva are called ammocoetes they strongly resemble primitive chordates and filter feed for 3-7 years Lamprey also die after spawning.
How do petromyzontida feed?
parasitic jawless so they attach and rasp flesh then produce anticoagulants to avoid clotting and lap up fluids.
What is significant about hagfish reproduction?
Can change sex seasonally.
What does the adaption of jaws do for Gnathostomes? and what does this change mean regrading locomotion?
jaws allow you to eat larger more active prey, so as a result paired fins are developed as well for greater speed.
What structure did gills evolve from?
collagen gill arches turn into cartilage gill arches and turn into jaws.
Name three types of Gnathostomes
Chondricthyes (cartilage skeleton), Actionpterygii (ray finned fish), Sarcopterygii (lobe- finned fish).
Name the groups of Chondricthyes from class.
Elasmobranchi (Sharks, skates, rays), Holocephli( Ratfish)
Name the groups of Actionpterygii from class
Chrondrosteans (primitive ray finned fish), Neopterygians (teleosts)
What type of tail does Elasmobranchi have?
Heterocercal (helps with buoyancy by pushing the fish up slightly as it swims).
What does Elasmobranchi lack that all ray finned fish have and what does it use instead to make up for it?
They lack swim bladders so to maintain buoyancy they have very large livers and secrete Squalene (oils) that are buoyant.
What type of scales do Elasmobranchi have? and what are they made up of?
Placoid scales( arrow head shaped), same as our teeth the outer layer is enamel with a inner layer of dentin and a pulp cavity in the middle.
What is significant about sharp teeth?
They are modified placoid scales and they grow in rows starting from the back of the mouth and rolling up and out like a convert belt when they are needed.
Why is significant about Elasmobranchi's intestines?
they are very short so to make them more efficient they have a spiral valve with forces food to take longer to pass through the intestines.
Are Elasmobranchi osmotic?
Sharks are iso-osmotic which means they have the same salt content in their body as their environment and this means less water is lost from the body (equal pressure).
Where does water enter for respiration in Chondrichthyes?
Enters through mouth and spiracles and passes through gill slits. Rays have spiracle openings on top of their body because they sit in sediments for long periods of time.