Phylum Chordata Continued Chapter 11 The Vertebrates Phylum Chordata Continued Chapter 11

Vertebrate Characteristics They are chordates, so they have what 4 characteristics? Plus – vertebrates also have a backbone of vertebrae

What vertebrates include and some of the distinguishing characteristics

According to this figure, lobe-finned fish are excluded from the tetrapods because they lack which of the following characters? A) vertebral column D) lobed appendages B) jaws E) legs with multiple digits C) lungs or lung derivatives

3 tissues, true coelom – same as seen in invertebrates Gill slits only seen in embryo Most primitive are considered the jawless fishes: hagfish and lampreys Hagfish have head, but no vertebrae – still only supported by a notochord 40 spp of hagfish – scavengers on ocean bottom; slime = defense, skin used to make fake eel skin belts & purses

What trait is shared by all animals? Generate carbon-based molecules by photosynthesis Heterotrophic – eat other organisms as a source of energy and carbon They are motile through all stages of their life They have vertebrae They have three embryonic tissues that give rise to all of the organ systems and body wall. Check question

Fishes Jawed – hinged for biting and chewing Some have cartilage skeleton Some have boney skeleton Cartilage fish must swim to stay up in open water and to move water over their gills. Boney fish swim bladder = develops into a lung in lobed fin fishes used to gulp air in shallows to augment oxygen from gills.

Fishes (con’t) Ray-finned Fishes Lobe-finned Fishes Fins have rays – for more flexible movement Swim bladder provides buoyancy Operculum – protective cover over gills, creates flow of water over gills without swimming being necessary Lobe-finned Fishes Fins have rod-shaped bones in two sets of paired fins Fins allow for “walking” on bottom Common in fossils, some living forms like Lungfish Gave rise to terrestrial vertebrates Coelacanth; During Devonian (400 mya), lots of swamps with temporary pools of water. Fish would walk between ponds on fins and gulp air into sacs for oxygen while out of water.

The first vertebrate with a head and skull probably resembled a A) lobe-finned fish. B) lancelet. C) hagfish. D) lamprey. E) shark.

First show up in fossil record about 375 mya Breathe by pair of small lungs, also across skin Skin is thin, can dry out, so need to stay in moist areas (also need wet surface for gas exchange)

Transition water to land

Reptiles Snakes, lizards, alligators, turtles, dinosaurs, crocodiles Birds evolved from reptiles and your book includes them as reptiles

Amniotic Egg Leathery in reptiles (not birds)

Birds Many dinosaur features, including walking on hind legs and modified front limbs Egg shell different from that of lizards

Advantages of Flight Seasonal movements, finding food and nest material, avoiding predators, etc.

Cuticle seals plant surfaces and helps plants conserve water and the seed helps derived plant groups to reproduce effectively on dry land. The analogous adaptations in reptiles are ________ (analogous to cuticle) and ________ (analogous to the seed). A) scales . . . jellylike egg masses B) scales . . . the amniotic egg C) scales . . . aquatic larvae D) claws . . . lungs E) moist skin . . . jellylike egg masses

Mammals Terrestrial, secondarily aquatic Three major groups: Monotremes – egg laying Marsupials Placental mammals Whales, dolphins, etc.

Monotremes Duckbilled platypus, spiny anteaters (echidnas) Evidence that mammals evolved from reptiles just like birds Very few species

Marsupials Kangaroos, wallabies, opossum, koala, squirrel gliders, Tasmanian tiger (extinct) Young born very small

Placental Mammals Young develop inside female, where kept hydrated without the egg Internal development in female uterus = protection from predators and other ways eggs can be damaged Placenta makes internal development possible Mammary glands used to feed young

What vertebrates include and some of the distinguishing characteristics

Transition from moist to terrestrial environment -what problems needed solving? Protection of outer body – prevent desiccation Respiratory surface that remains wet (required for gas exchange of O2 and CO2) Animals, plants and fungi

Transition from moist to terrestrial environment -what problems needed solving? Reproduction – sperm need to reach egg without drying out Sperm is transferred in packets Direct transfer into female track using appendage Protect young from desiccation during development Egg Internal development Oceans – sperm released into water; Other? - plants we’ll see

Activity

Read chapter 12 Plant and Fungi Diversification