18 Flashcards
How many species approx of fish?
30,000
The synapomorphies that group fish? 2*
*Gills arches,
*Paired Lateral fins
The fish that tetrapods and modern animals evolved from?
Lobe-finned Fish
Chordates synapomorphies? 3*
Synapomorphies:
*Notochord (a rod that runs the length of the body)
*Post-anal tail: an extension of the body that propels the animal forward
*Dorsal hollow nerve cord: since we are deuterostomes, our nervous system runs along the dorsal part of the body. The spinal fluid moving inside the ventricles of the brain.
Notochord?
Helps resist compression and aids in propulsion. It can’t be compressed. This allows it to contract the muscles around it and move the tail side to side. Without a stuff notochord, the tail will be pushed to the head.
!!!Dorsal hollow nerve cord (DHNC)?
Derives from ectoderm that rolls into a hollow tube during development. In Chordates, it is located dorsally to the notochord.
!!!How does DHNC develops?
When it is time to make DHNC, the dorsal ectoderm
Taxons within Chordates?
*Chephalochordate
*Urochordates
Chephalochordates?
Filter feeders, have gill arches that eventually evolve into jaws later in the tree of life. Post anal tail moving via alternating contractions of left and right body muscles.
!Urochordates?
Have a notochord, DHNC, and post-anal tail. However later in life, they undergo metamorphosis.
Two clades within vertebrates?
*Jaw-less fish called cyclostomes
*Gnathostomes
!!!Lampreys?
Jawless
Hagfish?
Jawless cyclostomes: eat mostly dead fish, no paired-lateral fins
Gnathostomes jaws evolve from?
Pharyngeal gills
Chondrichthyans?
cartilage which defines this group of sharks. Males also have claspers on their pelvis.
Osteichthyes?
Bone which defines this group of bony fish including ray-finned fish.
Ray-finned fish?
Bony rays that support their fins.L
Lobe-finned vertebrates?
Unique structure to their fins. A single large bone that attaches the limb to the body. It gives this lobe finned property.
Coelacanths?
Thought extinct 65Mya until 1938.
Lungfish?
Sister to tetrapods, and can breathe in air and water.
Middle ear bones are homologous with?
Shark’s jaws
Gnatostome skull parts?
*Hymandibula: supports the jaw
*Palatoquadrate: Upper Jaw
*Mandibular Cartilage: Lower Jaw
What does the Hymandibula mean about the bites of sharks?
Their bites can separate from the skull since their jaws are not connected to the skull.
Early tetrapod skull?
The jaw is attached to the skull through the quadrate. There is a join called the jaw joined. The articular forms the jaw joint. The hyomandibula transmits sound to the ear region of the skull and no longer supports the jaw.
!!!Adult mammals have how may bone in the lower jaw?
The denture, that articulates directly with the skull. The articular becomes the hammer bone (malleus), the quadrate becomes the incus or anvil bone in the middle ear, and the hyomandular into the stapes, the articular evolves into
Neural crest cells?
A special set of cells that are formed at this point from ectoderm in association with the formation of the neural tube. These cells are unique to vertebrates and form important structures such as the cartilage and bones of the face. All the bones in the front of your face is formed from the neural crest cells.
Neurocranium is formed from?
Mesoderm while the facial ones are formed from neural crest these two regions of the skull are developmentally independent. There is a flexible arrangement.
Tetrapods?
*Synapomorphies: 4 legs, 5 or more digits
Marine, freshwater, terrestrial.
Groups within tetrapods?
*Amphibians
Amphibians differ from other tetrapods because?
They need to lay their eggs in the water.
The transition from water to land developed?
Amniotes
Amniotes synapomorphy?
Amniotic egg, which has a series of membranes surround the developing embryo.
!!!Amniotic egg structure? 4*
*Shell
*Amniotic membrane
*Allantois
*Cholin
Amniotes include what clades?
Reptiles and mammals
Turtles?
One of the oldest group of reptiles. Marine, freshwater, terrestrial, herbivores predators. Synapomorphy: skeleton that expanded into the skull.
Archosaurs include?
Crocodilians, Pterosaurs, Dinosaurs
Crocodillians?
Synapomorphy: secondary bony palate, convergent with mammals, allows them to breathe and eat.
Pterosaurs?
Extinct winged reptiles. Later triassic to end of cretaceous.
Dinosaurs modified pelvis allowed?
better mobility
Groups that share modified Elvis?
Ornithischians, Saurischians
In ornithischians, the pubis bone is oriented?
Posteriorly
!!!Saurischians?
Synapomorphies: Pubis bone oriented anteriorly
Mammals synapomorphies?
Synapomorphies: hair and mammary glands is the presence of a soft palate
The presence of a soft palate in mammals allowed mammals to?
Breathe and eat at the same time.
Prototherians groups?
*Platypus
*Echidnas
What is the only mammalian group that lays amniotic eggs?
Prototherians
Metatherians?
Synapomorphy: pouch
Embryonic young climb into pouch to reach nipples
Eutherians?
Synapomorphy: placenta
Placental mammals?
Embryo develops inside the mother in a placenta.
The placenta evolved from?
Evolved from the amniotic egg and has all the same embryonic support membranes.
Metatherians and Eutherians are an example of convergent evolution by?
They evolved to look like moles, flying squirrels, and wolves.
the 1-2-5 limb pattern of all tetrapods?
A part of the lobe-finned vertebrae clade, which means that there is one large proximity
