
1. Chondrichthyes
1.1. Ex: sharks, rays, skates
1.2. Subclass has some species of ratfish and chimaeras
1.3. Skeleton primarily made of cartilage
1.4. Some suspension feeders, but mostly carnivores
1.5. Have short digestive tract with ridge called spiral valve to increase digestive surface area
1.6. Has acute senses of smell, sight, and can detect electrical fields
1.7. Eggs fertilized internally, but can develop in 3 different ways
1.7.1. Oviparous: eggs hatch outside mother's body
1.7.2. Ovoviviparous: embryo develops within uterus nourished by egg yolk
1.7.3. Viviparous: embryo develops within uterus nourished by yolk sac placenta from mother's blood
1.8. Reproductive tract, excretory system, and digestive trace empty into cloaca
2. Enchinodermata
2.1. Ex: starfish
2.2. Slow-moving or sessile
2.3. Thin epidermis covers hard calcareous plates
2.4. Has unique water vascular system
2.4.1. Network of hydraulic canals branching into tube feet functioning in locomotion and feeding
2.5. Sexual reproduction is external
2.6. Most have radial symmetry in multiples of 5 (penta-symmetry)
2.7. Larva have bilateral symmetry
2.8. Divided into five clades:
2.8.1. Asteroidea: sea stars & sea daisies
2.8.1.1. Sea stars:
2.8.1.1.1. Multiple arms radiate from central disk
2.8.1.1.2. Arms grip with tube feet that have adhesive chemicals
2.8.1.1.3. Eat bivalves by prying them open with tube feet and digesting them externally
2.8.1.1.4. Can regrow lost arms
2.8.1.2. Sea daisies
2.8.1.2.1. Armless
2.8.1.2.2. Only 3 know species
2.8.1.2.3. Live on submerged wood absorbing nutrients through membrane surrounding body
2.8.2. Ophiuroidea: brittle stars
2.8.2.1. Distinct central disk
2.8.2.2. Long, flexible arms
2.8.2.3. Some are suspension feeders, others are predators or scavengers
2.8.3. Echinoidea: sea urchins & sand dollars
2.8.3.1. No arms but 5 rows of rube feet
2.8.3.2. Spines used for locomotion and protection
2.8.3.3. Sea urchins eat seaweed using "jaws" on underside
2.8.4. Crinoidea: sea lilies & feather stars
2.8.4.1. Sea lilies:
2.8.4.1.1. Live attached to substrate by stalk
2.8.4.2. Feather stars:
2.8.4.2.1. Crawl using long, flexible arms
2.8.4.3. Both are suspension feeders
2.8.4.4. Changed little through evolution
2.8.5. Holothuroidea: sea cucumbers
2.8.5.1. Lack spines
2.8.5.2. Reduced endoskeleton
2.8.5.3. Dissimilar looks to other enchinoderms
2.8.5.4. 5 rows of tube feet, some used as feeding tentacles
3. Reptilia
3.1. Ex: tuataras, lizards, snakes, turtles, crocodilians, and birds
3.2. Have scales to make waterproof barrier
3.3. Most ectothermic: internal termperature mostly regulated via external sources
3.4. Birds are endothermic: capable of independant internal termperature regulation
3.5. Turtles:
3.5.1. All have boxlike shell of upper and lower shields fused to vertebrae, clavicles, and ribs
3.6. Diapsids:
3.6.1. Archosaurs:
3.6.1.1. Crocodilians: belong to lineage dating back to late triassic
3.6.1.2. Birds: nearly every part of body adapted for flight: wings with keratin feathers, lack of urinary bladder, females have 1 ovary, small gonads, and no teeth
3.6.1.2.1. Belong to clade neornithes
3.6.1.2.2. Several groups of birds are flightless:
3.6.2. Lepidosaurs:
3.6.2.1. Tuataras: one surviving species: lizard-like reptiles called tuataras, along with one surviving lineage
3.6.2.2. Squamates: major living lineage which includes lizards and snakes
3.6.2.2.1. Snakes: have chemical sensors, heat-detecting organs, venom, loosely articulated jawbones, and elastic skin
3.6.2.2.2. Lizards:
4. Mammalia
4.1. Amniotes that have: mammary glnds tht produce milk, hair, high metabolic rate due to endothermy, larger proportional brain size to other vertebrates, differentiated teeth
4.2. Are synapsids
4.3. By early cretaceous, 3 living lineages appeared
4.3.1. Monotremes:
4.3.1.1. Ex: echidnas, platypus
4.3.1.2. Egg laying mammals
4.3.2. Marsupials:
4.3.2.1. Ex: opossums, kangaroos, koalas
4.3.2.2. Embryo develops within placenta in mother's uterus
4.3.2.3. Completes development while nursing in maternal pouch called marsupium
4.3.3. Eutherians:
4.3.3.1. Have more complex planceta than marsupials
4.3.3.2. Completes development within uterus, joined to mother by placenta
4.4. Primates:
4.4.1. Ex: lemurs, tarsiers, monkeys, apes, humans
4.4.2. Traits: large brain, short jaws, hands/feet adapted to grasping, short nails, complex social behavior and parental care, forward-facing eyes close together on face, and fully opposable thumb
4.4.3. Three main groups:
4.4.3.1. Lemurs, lorises, and bush babies
4.4.3.2. Tarsiers
4.4.3.3. Anthropoids (monkeys and apes)
4.4.3.3.1. New world monkeys
4.4.3.3.2. Old world monkeys
4.4.3.3.3. Apes: diverged rom old world monkeys about 25-30 mya
5. Actinastia
5.1. Ex: coelacanth
6. Actinopterygii (ray fins)
6.1. Ex: yellowfin tuna
6.2. Fins modifed for maneuvering, defense, and other stuff
7. Cyclostomes
7.1. Myxini (hagfish)
7.1.1. Have cartilaginous skull
7.1.2. Have reduced vertebrae
7.1.3. Have flexible rod of cartilage derived from notochord
7.1.4. Have small brain, eyes, ears, and "teeth"
7.1.5. Marine, most are bottom-dwelling scavengers
7.2. Petromydontida (lampreys)
7.2.1. Parasites that eat by clamping mouth to live fish
7.2.2. Inhabit marine and freshwater spots
7.2.3. Have cartilaginous segments surrounding notochord
7.3. Lack backbone, but have rudimentary vertebrae
7.4. Only 2 remaining lineages of jawless vertebrates
8. Dipnoi
8.1. Ex: lungfish
8.2. Gills main organs for gas exchange, but also surface to gulp air
8.3. 1/3 surviving lobe-fins are tetrapods, a group that adapted to land
9. Amphibia
9.1. Contains 3 clades:
9.1.1. Urodela: salamanders
9.1.1.1. Amphibians with tails
9.1.1.2. Paedomorphosis is common in aquatic species
9.1.1.2.1. Paedomorphosis: retention of juvenile features in sexually mature organisms
9.1.2. Anura: frogs
9.1.2.1. Powerful hinds legs
9.1.2.2. Frogs with leathery skin are called toads
9.1.3. Apoda: caecilians
9.1.3.1. Legless, nearly blind, and resemble earthworms
9.1.4. Amphibian means "both ways of life"
9.1.5. Most have moist skin to help lungs with gas exchange
9.1.6. Fertilization external in most species, and eggs require moist environment
9.1.7. Some have males or females carry eggs on back, in mouth, or in stomach
10. Cephalochordata
10.1. Ex: lancelets
10.1.1. Named for bladelike shape
10.1.2. Marine suspension feeders
10.1.3. Retain characteristics of chordate body plan as adults
11. Urochordata
11.1. Ex: tunicates
11.1.1. Resemble chordates during larval stage
11.1.2. Draw in water through incurrent siphon, filtering food particles
11.1.3. Highly derived & have less Hox genes than other vertebrates
12. Chordates
12.1. All have notochord and dorsal, hollow nerve cord, pharyngeal slits or clefts, and post-anal tail
12.1.1. Notochord: longitudinal, flexible rod between digestive tube and nerve cord. Provides skeletal support
12.1.2. Dorsal nerve cord: develops into brain and spinal cord
12.1.3. Pharyngeal clefts: develop into slits opening outside of body. Suspension-feeding structures in invertebrates, gas exchange in vertebrates (except tetrapods, they develop parts of ear, head, and neck)
12.1.4. Post-anal tail: Often reduced during embryonic development
12.1.5. Contains skeletal elements and muscles
12.1.6. Provides propelling force in many aquatic species