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Description
Flashcards by Becca McNally, updated more than 1 year ago
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Created by Becca McNally
over 6 years ago
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| Question | Answer |
| What does the phylum Chordata consist of? | Muscular post-anal tail Muscle Segments Anus Notochord Dorsal, hollow nerve cord Pharyngeal slits and clefts Brain Mouth |
| What are Cephalochordata? | They are Lancelets. There are 32 species in shallow seas. These are filter feeders that use a mucous net to catch food. |
| What are Urochordata? | They are marine filter feeders that consist of Tunicates. There are 3,000 species that are sessile and benthic. Tunicates are planktonic larva. |
| What is the 2R Hypothesis? | The Chepahlochordates and Tunicates have a single gene, whereas vertebrates have 2-4 equivalent genes. They have 2 whole-genome duplication events that occur (564-450 MYA). |
| What are Vertebrata? | Vertebrata first originated in the lower Cambrian period and now contain 66,000 species. They are similar to cephalochordates but contain a large brain, skull, eyes and "teeth". |
| What are Myxini (Hagfish)? | They are marine scavengers containing 30 species. They contain a cartilaginous skeleton, jawless and notochord. They come from the Cambrian period. |
| What are Petromyzontida (Lampreys)? | They are jawless, larvae filter feeders, that contain a notochord and simple vertebral column. There are 35 species that live in both marine and freshwater environments. |
| What is the Evolution of Jaws? | Jaws are efficient for feeding and provide a wider range of food items. They first came in the early Silurian era but probably evolved from the early Ordovician (500-440 MYA) |
| What are the 4 clades of Chordates? | Chondrichthyes Placoderms Acanthodians Osteichthyes |
| What are the 2 orders of Chondrichthyes? | Elasmobranchii (sharks, skates and rays)- 1150 species Holocephali (chimeras)- 50 species |
| What are the Characteristics of Chondrichthyes? | Cartilaginous skeleton (reinforced small bone plates) Jaws and paired fins Developed smell and lateral line system No swim bladder Carnivores Internal fertilisation (modified pelvic fins to transfer sperm) Ovipary to Vivipary Few offspring |
| What are the 3 clades of Actinopterygii (Fin fish)? | Chondrostei (sturgeons and paddlefish)- 45 species Holostei (Gars and Bowfin)- 9 species Teleostei (Ray-finned fish)- 27,000 species |
| What are the Characteristics of Fin fish? | Ossified endoskeleton (bones) Skin scales and Mucus Swim Bladder Teleosts (fins supported by rays, jaw modifications) External fertilisation and pelagic larvae (huge egg no. and some fish show parental care) Oviviparous and Viviparous |
| What are Actinista (lobe-finned fish)? | There are 2 living species; Coelacanth, Latimera and were rediscovered in 1938 after an 80 year absence. They have fleshy fins, hinged skull and are Ovoviviparous |
| What are Dipnoi (Lungfish)? | They are fish found in swamps and shallow pools normally located in the southern hemisphere. There are 6 species in the world and evolved from the lower Devonian period. They get their name lungfish due to being able to fill their lungs with air. They are living relatives to tetrapods |
| What are Osteichthyes? | Osteichthyes are jaws and mineralized skeletons |
| What are Tetrapods? | Amphibia Amniotes (reptiles and mammalia) |
| The Tetrapods origin | 1st Amphibians (late devonian- 375 MYA) They are Carboniferous. The limbs evolved from fins of lobe-finned fish. Lungfish are the closest living relatives to tetrapods. |
| What are the 3 orders of Amphibia? | Urodela (newts and salamanders- 650 species) Anura (frogs and toads- 6,200 species) Apoda (Caecilians- 190 species) |
| What are the Characteristics of Amphibia? | Skin with limited keratinisation Permeable oxygen and water skin Restricted to damp environments Fertilisation external No shell eggs (prone desiccation and need physical support) Larvae fish-like with gills (lateral line system that lacks legs or lungs. They have Aquatic herbivores) Terrestrial carnivores (lungs and 4 legs) |
| What is the Amniotic egg? | 4 specialised membranes to protect from desiccation, allow gas exchange and store food and waste. It allows amniotes to be terrestrial. They evolved from Carboniferous. |
| What is the Amniotic egg origins? | The Hylonomus is the oldest amniote that dates back to the carboniferous period 312 MYA. However it is said that westlethiana is said to be an older amniote from 338 MYA. |
| What are the 2 main clades of amniotes? | Reptilia Mammalia |
| Odontochelys | Ancestral turtle, late triassic of China 220 MYA The shell is only on the underside |
| Testudines (Turtles) | 327 species Terrestrial, freshwater and marine Shells and Skeleton unique to clade |
| Turtle Charcateristics | Skull Morphology Scales (B-Keratin) Internal Fertilisation (lay eggs) Ectothermic |
| Crocodilia (crocidiles & alligators) | 24 species Semi-aquatic predators; tropical Changed little since triassic Secondary palate Heart with Septum |
| What was the first bird? | Archaeopteryx was found in the Jurassic period from 150 MYA. It is a mixture of reptilian and avian characters. |
| Aves (Birds) | Approx. 10,000 species It has a Global distribution in most habitats |
| Birds Characteristics | Feathers (B-Keratin) Large, keeled sternum Fore-limbs modified for flight Hind-limbs bipedal walking Internal fertilisation, hard-shelled amniotic eggs Endothermic |
| Sphenodontia (Tuatara) | 1 species lizard-like, carnivorous reptile that was found off the coast of New Zealand. It is a diverse group but were mostly extinct in 65 MYA. The skull differs from lizards but retains ancestral features. |
| Squamata (snakes & lizards) | 9,800 species Tropical, terrestrial carnivores Lizards have ancestral body plan & characters Snakes are highly specialized being limbless, elongate and have modified jaws and skull. |
| What are the Origins of Mammals? | Hadrocodium wui They were first from the Jurassic period 195 MYA. They had a large brain, malleus and incus in inner ear as in modern mammals. |
| Mammalia | Approx. 5,450 species Worldwide distribution in almost all ecosystems |
| What are the Characteristics of Mammalia? | Hair (a-Keratin) Specialised Teeth (heterodont) Articulation of jaw between dentary and squamosal bones Endothermic Internal Fertilisation Amniotic eggs Mammary glands |
| Linnaean Classfication | Linnaeus 1758 intoduced hierarchial structure and binomial nomeclature. Linnaean systems underlies all non-phylogenetic systems of taxonomy. This evolutionary theory had little impact on systems of classification |
| Classification Order | Kingdom-Kings Phylum-Put Class-Crowns Order-On Family-For Genus-Good Species-Sex |
| What are the Classes of Vertebrates? | Agnatha (Lampreys and Hagfish) Chondrichthyes ( Elasmobranchs) Osteichthyes (Bony Fish) Amphibia (Amphibians) Reptilia (Reptiles) Aves (Birds) Mammalia (Mammals) |
| Origins of Archaeopteryx | Derived from Reptiles 4 Hypothesis 1) Thecodonts (Archosaurs) 2) Crocodylomorphia (crocodiles) 3) Saurischia (lizard-hipped dinosaurs) 4) Ornithischia (bird-hipped dinosaurs) |
| Fossil Birds | Not Extensive Debate over classification and date of fossils Oldest is Archaeopteryx (without feathers, not widely held to be ancestors) |
| Fossil Birds Phylogenetic Classification | Phylogeny- evol. history of organism or group Cladistics- classification using hypothesised evol. relationships among organisms |
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