Animals III: Deuterostomes Flashcards
What are Deuterostomes
Deuterostomes have 3 true tissues and a coelom, part of Bilateria
Mainly Echinoderms and Chordates
What are Echinoderms
Echinodermata includes Brittle Stars, Sea urchins, Sand dollars, Sea Stars, Sea Lilies, Feather Stars, Sea Cucumbers
They have a thin epidermal layer over an endoskeleton of hard plates; unsegmented
How do Echinoderms Circulate, Move, Feed, and reproduce
They have an Open circulatory system called the water vascular system
They use tube feet for locomotion and feeding
They perform sexual reproduction with separate males and females
what defines chordata
Four defining characters of Chordata
- Notochord
- Dorsal Hollow nerve cord
- Musular post anal tail
- Pharyngeal slits or clefts
they are also segmented and have a closed circulatory system
What are invertebrate chordates
Vertebrates are a subphylum of Chordates
Excluding Lancelets (Cephalochordata) which do suspension feeding and look like long tubes and have free living adults
and Tunicates (Urochordata) juveniles are mobile and don’t feed, and adults are sessile and do suspension feeding
What do all vertebrates have
All extant Vertebrates have a vertebral column and a Cranium (skull)
what are Cyclostomes
Cyclostomes: Jawless fishes’, have a partial or full cranium and a vertebral column of cartilage
- Hagfish are marine scavengers famous for their protective slime
- Lampreys are parasitic or predaceous and often migrate between marine and freshwater
What are Chondrichthyans
Chondrichthyans: Cartilaginous fish
- sharks, rays, skates, and chimaeras
- have a jaw and a skeleton made of cartilage, but mineralized teeth
What are Osteichthyans
Osteichthyans: Bony fish
- mineralized skeleton and swim bladder
- most diverse vertebrates and most abundant
What are Tetrapods
Tetrapods: Land dwellers, four legs
Amphibians, Reptiles, Mammals
what are Amphibians
Amphibians:
- salamanders and Newts
- Frogs and Toads
- Caecilians
- Terrestrial adults
- eggs and immature stages are aquatic
What are Reptiles
Reptiles:
- have amniotic eggs, shelled eggs that allowed vertebrates to fully leave land
- Includes birds
- lay eggs on land
What are Mammals
Mammals
- amniotes
- fur and hair
- produce milk (lactate)
- monotremes
- marsupials
- eutherians (placental)
Summarize animals in terms of Coelom, Circulatory system, and Segmentation
Platyhelminthes don’t have a coelom, or circulatory system, and aren’t segmented
Mollusca have a coelom, either open or closed circulatory system, and no segmentation
Annelids have a coelom, closed circ system and are segmented
Nematodes have a pseudocoelom, no circ system, and no segments
Arthropods have a coelom, open circ system, and no segmentations
Echinoderms have a coelom, open circ system, and no segmentations
Chordata have a coelom, closed circ system, and are segmented
What are Hemichordates
Deuterostomes close to Echinoderms
Acorn worms are Hemichordates and are found in the substrate at the bottom of the ocean
What animals are Echinoderms
- brittle stars
- sea urchins
- sand dollars
- sea stars
- sea lilies
- feather stars
- sea cucumbers
What are Echinoderms like
Echinoderm larvae have diverse but bilaterally symmetric shapes
They are free living and planktonic
Most Echinoderm adults are slow moving predators or scavengers on the ocean floor, though some can float or swim
All are marine
What kinds of cords do Chordates have
- have a hollow nerve cord develops from the ectoderm
- the notochord is a longitudinal flexible rod between the digestive tube and nerve cord, It provides skeletal support
- Chordates began in the Cambrian explosion 540 mya
What does Vertebrata include
Vertebrata is a subphylum of chordates
includes
- Cyclostomes - hagfish (Myxini)
- Petromyzontida - Lampreys
- Chondricthyans - ray finned fish
- Acthistia (Coalacanths)
- Dippoi (Lungfish)
- tetrapoda - amphibians, reptiles, and mammals
What were early vertebrates like
early vertebrates were small lancelet like and covered with bony plates and lacking jaws. Originated in the midlate cambrian
What two groups of vertebrates first gained jaws
Jaws evolved from gill arches in Chondrichthyans, posses a jaw and skeleton of cartilage but have mineralized teeth.
Also has skin teeth called dermal denticles
Placoderms were an extinct line of jawed vertebrates split from chondrichthyans, had mineralized skulls and bony plates. Impacted ocean ecology and evolution
What did bony fish do
Osteichthyans “bony fish”
includes Dipnoi, lungfish
Lungs led to early fish like Tiktaalik with features that may have permitted land colonization
Lungs may have evolved first then been turned into swim bladders
To colonize land the evolution of leg and then eggs was important
What is the amniotic egg
The amniotic egg is used by reptiles and mammals to become fully independent of water
How did amniotes conquer the skies
Once on land amniotes evolved flight 3 times, allowing them to conquer new habitates and habits
Pterosaurs, birds, and bats
flight was derived from the dactyles “finger things” shared ancestral
What kinds of vertebrates lost legs
They have also lost legs a number of times
- snakes
- legless lizards
- caecelians
What are mammals
Mammals are amniotes with fur / hair and produce milk (lactate)
What are the three groups of mammals
monotremes - platypuses, echidnas, lay eggs, don’t have nipples, milk is on fur
Marsupials - kangaroos, Opossums, Koalas, etc, complete embryonic development in a pouch on the mother’s body
Eutherians (Placentals) - embryonic development in uterus, nipples / teats
How much do vertebrates range in size
Vertebrates have the largest range of body size
Paedophryne amauensis (7.7 mm frog) - Blue whale (30m)
