paleontology exam 1 prep (chapters 1-4)

• osteichthyes are bony fish
• chondrichthyes are cartilaginous fish
• the first vertebrates were chordates, which had a notochord.
• amphibians have lungs, skin that can absorb oxygen, and lay eggs on land or water.
• Dunkleosteus


  massive predator (6-7 m long and weighing 3-4 tonnes). Dunkleosteus was a powerful carnivore, they are a predatory fish of the order plecoderm with robust Jaw and Sharp bony plates. They are an extinct genus of large plecoderms that lived during the upper Devonian. largest Devonian predator, with the first form of teeth aka spiky tooth like bony plates which allowed them to become predators.
• what is radiata?

  animals showing radial symmetry (body plan in which similar parts are arranged around a central axis.) example: starfish

  
• what is bilateria?

  animals showing bilateral symmetry ( body plan having two corresponding or complementary halves)

  
• what are the 5 characteristics of chordate?


  The 5 characteristics :

  • Notochord
  • Pharyngeal slits
  • Hollow, dorsal nerve cord
  • Postanal tail
  • Endostyle or Thyroid
• ostracoderms


  The armored Jawless fishes from the early palaeozoic are sometimes referred to as ostracoderms (armour skins), a term that does not refer to a clade but to a collection of clades of Jawless vertebrates on the gnathostome stem. (Ancient Jawless fish known for their bodies covered in bony armour and lived on the sea floor)
• placoderms include the first vertebrates to have ______ ______ ____.


  paired pelvic fins.
• Vertebrates are animals with backbones, including fishes, amphibians, reptiles, birds, and mammals
• Vertebrates are of interest because they include humans
• Living vertebrates are part of the Phylum Chordata, which also includes marine animals like sea squirts and amphioxus
• Chordates share features such as a notochord and V-shaped muscle blocks (myomeres) along the body
• Sea squirts, or tunicates, are part of the Urochordata group of non-vertebrate chordates
• Sea squirts have a bag-shaped body with gill slits, a pharynx, and a heart
• Sea squirts filter food particles from seawater using their pharynx and endostyle
• Sea squirt larvae have a notochord, muscles, and a simple brain, identifying them as chordates
• Amphioxus, or lancelet, belongs to the Cephalochordata group of non-vertebrate chordates
• Amphioxus is paperknife-shaped, lacks a head, and filters food particles from seawater using its pharynx and endostyle
• Amphioxus anatomy includes a pharynx, notochord, dorsal nerve cord, myotomes, and endostyle
• Ambulacraria includes echinoderms and hemichordates, unexpected relatives of chordates
• Echinoderms have a calcite skeleton, water vascular system, mutable collagen, and pentaradial symmetry
• Living echinoderms include starfish, sea urchins, brittle stars, sea lilies, and sea cucumbers
• Hemichordates consist of pterobranchs and acorn worms, with different marine adaptations
• Pterobranchs like Cephalodiscus live in colonies, filter food particles using cilia, and construct tubes for habitat
• Acorn worms like Saccoglossus are worm-like animals with a muscular proboscis, living in burrows on the shore
• Hemichordates live in burrows low on the shore in Europe and elsewhere
• Saccoglossus has a long muscular proboscis that fits into a fleshy ring or collar behind
• Glacial erosion is the breaking down and removal of rocks and sediment by natural forces
• In glacial environments, the 2 main forms of erosion are abrasion and plucking
• Abrasion:

  • A sandpapering effect caused by small rocks embedded within the glacier rubbing on bedrock
  • Usually leaves a smooth surface with scratches called striations
• Plucking:

  • Meltwater from glaciers freeze around broken or cracked parts of rock, breaking it off from the bedrock or sides as the ice moves down the slope
  • Most prominent when there are many joints in the rock, as water can penetrate the rock and freeze in the cracks
• Hemichordates do not have a notochord at any stage, but they possess gill slits, as in chordates, and giant nerve cells in the nerve cord of the collar region
• Embryology: The blastopore becomes the anus in deuterostomes, including chordates, and the mouth is a secondary perforation
• Metazoa, Bilateria, and Deuterostomia are monophyletic groups, or clades
• The Bilateria have bilateral symmetry primitively, and most are triploblastic, meaning they have three fundamental body wall tissues that arise from the ectoderm, mesoderm, and endoderm in the embryo
• Protostomes include the Ecdysozoa and Spiralia, while Deuterostomia is divided into the two major clades Protostomia and Deuterostomia
• Most spiralians belong to the clade Lophotrochozoa
• Deuterostomia is confirmed as a monophyletic group by both morphology and phylogenomics