Vertebrate Diversity
Terms
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- phylum Chordata includes which subphyla
- Urochordata (tunicates), Cephalochordata (lancelets), and Vertebrata (fishes, amphibians, reptiles, birds, and mammals)
- Traditional systematics (evolutionary systematics)
-
developed in an attempt to order and classify the large number of species being described.
ex. kingdom, phylum, class - phylogenetic systematics (cladistics)
- scientists try to classify organisms based upon evolutionary relationships
- cladograms
- the trees of evolution
- clades
- the branches are always dichotomous with each branch representing divergence
- monophyletic
- a grouping that consists of an ancestral species and all of it's descendants
- Archosauria include which animals?
- include crocodiles and alligators, dinosaurs, and birds
- Why might two systems generate different trees?
- b/c scientsits rank the importance of the characteristics differently.
- derived characters
- newl acquired characters, distinct from ancestral characters
- How can there still be different cladograms with same data?
- it depends upon how the scientist weigh each parameter.
- What are considered in constructing the tree? There are 5
- ecology, behavior, physiology, morphology and DNA sequence
- How does adaptation lead to function?
- it enchances evolutionary fitness and that arose historically as a result of natural selection for its current biological role
- Diversity
- refers to the number of species within a specific lineage (e.g. vertebrates, or primates, or the genus Homo)
- disparity
- refers to the range of anatomical structural variation (e.g. body shape, or brain complexity)
- convergent evolution
- fromation of structures that have similar function.
- homologous evolution
- eventual fomration of structures from similar developmental structures. final outcome may be drastically different in the organisms being examined.
- What four characteristics set Chordata aprt from other phyla?
-
1. notochord
2. dorsal hollow nerve cord
3. pharyngeal gill slits
4. postanal tail
always found in embryo - What other feautres associates with chordate?
- enlarged sense organs, closed circulatory system with a ventral heart, cartilaginous endoskeleton, and segmented striated muscles
- When did Chordate first appear?
- Cambrian period about 550 million years ago
- What common characteristic is shared by all members of the chordata gropu?
- semi-rigid, rod like structure of vacuolated cells acts as skeletal axis for support of the body. All chordates have notochord at some time during their life
- What ancestral feautres did chordata inhereit?
- 3 germ layers, bilateral symmetry, well developed coelom, filter feeding, complete digestive tract, aand segmented body
- Whats the subphylum of Chordata?
- Urochordata - filter feeding
- paedomorphosis
- tunicate larvae capable of reproducing
- What is differenat about Vertebrates than Chordata
- have same features except notochord is replaced by vertebrae. Another is the brain.
- What other features do vertebrates have?
- Heart, cranium, and lateral line system (sense pressure changes/movement in water)
- What forms the unique endoskeleton of the vertebrates?
- carnium, visceral arches, limb girdles, and four jointed appendages
- When did the endoskeleton first appear?
- 500 million years ago Ordovician period
- functions of fins
- used for mtion, brakes, and tilting rudders
- lateral line system
- perceives water currents and vibration
- suction feeding
- draws water and prey in mouth for ingestion then goes to gills
- ostracoderms
- oldest undisputed vertebrates-small, heavily armored jawless fish with an expanded armored head with typical sense organs and a gill chamber.
- What has been the major driving force for evolution?
- the JAW
- What benefits does the jaw give?
- take in large prey quickly, can penetrate well armored prey. incrase metabolism rates, increase growth and levels of activity
- Agnatha
- jawless fish
- Gnathostomata
- jawed fish
- Hagfish
- bottom dwellers, somewhat lethargic, scavengers in the adult state. resemble eel. larvae filter feeders.
- name three classes that are jawed fishes
- placoderms, Chondrichthyes and Osteichthyes
- 2 classes of gnathostomes
- Chondrichthyes and Osteichthyes
- name animals in Chondrichthyes
- sharks, skates and rays.
- When did Chondrichthyes appear?
- 450 million
- 8 general traits of chondrichtyes
-
1. body fusiform (spindle shaped)
2. ventral jaws with teeth from modified skin. loosely bound
3. skin with placoid sscales (denticles)
4. endoskeleton of cartilage; notochord persistent, vertebrae complete and separate
5. swim bladder absent; fatty acid in liver
6. respiration 5-7 gills
7. two-chambered heart
8. osmoregulation retention of nitrogenous wastes in blood - Osteichthyes
- bony fish.
- What major unique feature in all osteichthyans? two other major innovations?
-
ossified endoskeleton
lungs, and red bone marrow - Actinopterygia
- ray-finned fish. (fish)
- teleosts
- marlins, perch, tuna
- initially what were swin bladders used for?
- respiration
- Sarcopterygia
- lobe-finned, or fleshy finned fish.
- Why is sarcopterygia important ?
- gave rise to first terrestrial vertebrates (tretrapods)
- Name 2 examples of living sarcopterygia
- coelacanth (Actinistia) and lungfish (Dipnoi)
- when was first sarcopterygians known?
- 400 million years ago Devonian period
- euryhaline
- can live in either fresh or seawater
- what are two main groups of tetrapods?
- amphibia and amniota
- Tetrapods unique features?
- fingers and toes; interlocking, stiffend vertebral column, hinged well msucled limbs; loss of dorsal fins; head and shoulder separated by neck; tongue; nostrils open into mmouth, loss of lateral line system, and a three chambered heart
- What three extant orders are there in Class Amphibia?
- Urodela (newts and salamanders), anura (frogs and toads), and Gymnophiona (caecilians)
- Where are Urodela found?
- almost all temperate and tropical regions
- Hyla
- smaller frogs
- gymnophiona
- limbless, burrowing/aquatic amphibians. bodies elongate, sensory tentacles on their head, skull often fused into fairly solid capsul
- Amniota
- vertebrates possess a true amniotic egg with a shell and three extra embryonic membranes (chorian, amnion, and allantois)
- what are the three extraembryonic membranes?
- chorion, amnion, allantois
- What were the amniote scales composed of in the Amniota?
- keratin