Lecture 1 Flashcards
What is systematics?
The study of biological diversity using phylogeny
Describe phylogeny
The evolutionary history and relationship between groups of organisms (e.g. species)
What does systematic knowledge provide?
A framework for interpreting biological diversity
As this is done in an evolutionary context, what does it allow?
Examination of how different attributes of animals change over time
What is taxonomy?
The description, identification and classification of species (new species are still being identified and described)
What is Nomenclature?
A standardised system of naming taxa
What is classification?
The arrangement and hierarchy of taxa (vertebrate classification is a mess- lots of subunits etc.)
What does phylogenetic systematics or cladistics suggest?
Shared derived characteristics constitutes evidence that the species possessing these features share a common ancestry. E.g. shared derived features represent unique evolutionary events that may be used to link species together in a common evolutionary history
What can relationships among taxonomic groups (e.g. species) be represented in?
In a cladogram or phylogenetic tree, a branching diagram that shows the best estimate of phylogeny based on the data used (e.g. genetic or morphology)
What derived characters used for?
To link monophyletic groups, groups of taxa that consist of a common ancestor plus all descendants of that ancestor
What are derived characters used for?
To link monophyletic groups, groups of taxa that consist of a common ancestor plus all descendants of that ancestor
What do paraphyletic and polyphyletic groups include?
A common ancestor and some, but not all, of the descendants of that ancestor
Give an example of a polyphyletic groups
Recent molecular data supports river dolphins as a polyphyletic group because Indian river dolphins do not share the same common ancestor as other river dolphins
What are chordates?
The animals that gave rise to the vertebrates with bilateral symmetry
What class of animals do the chordates belong to?
Deuterostomia
What do chordates have?
- notochord (dorsal rod of specialised nerves)
- dorsal nerve chord (hollow tube just above the notochord
- pharyngeal pouches (gill slits)
What are the 3 phyla of Chordata?
- Urochordata
- cephalochordata
- vertebrate
When did chordates evolve?
540 million years ago (Precambrian)
How many species of chordate are there?
52,000
Why are vertebrates good to use as a model for studying evolution?
. Monophyletic group
. Free living (most)
. Basic anatomy and development in common (common features)
. Diversity of form and function can be related to adaption and evolution
. Best studied eukaryotic group mainly because there is a very good fossil record
Give examples of myxinoidea and petromyzontoidea (jawless fish)
Hagfish and lampreys
Give examples of Elasmobranchii and holocephali (cartilaginous fish)
Sharks, rays, skates, rat fishes
Give examples of Actinopterygii (Ray-finned fish)
Bichirs, bowfins, gars, sturgeons, teleosts (most recent)
Give examples of Sarcopterygii (lobe-finned fish)
Coelacanths and lungfishes
What did sarcopterygii (lobe-finned fish) give rise to?
The terrestrial vertebrates
Give examples of Lissamphibia (amphibians)
Salamanders, frogs, caecilians
Give examples of amniotes
Reptiles, birds and mammals
Give the extant higher vertebrates: amniotes
. Testudines- turtles, tortoises, terrapins
. Lepidosauria- tuatara, lizards, snakes
. Crocodilia- alligators, crocodiles, caymans
. Aves- birds
. Mammalia- mammals
What are the most diverse group of extant vertebrates?
Ray-finned fish (Achinoterygii)
Give common features of vertebrates (look on the document for more)
. Postanal tail (for movement in some vertebrates)
. Pharyngeal pouches in lower chordates
. Vertebral column
. Specialised sensory organs, a lot of sensors to understand your environment
. Brain at anterior end of nerve cord, enhanced skull region that comes with a backbone
. Closed-loop circulatory system (heart, arteries, capillaries, veins)
. Myomeres (muscle segments)
What does the vertebral column develop from?
The notochord
What did the pharyngeal pouches in lower chordates evolve into?
Gill slits in fishes and amphibians, and structures in throat and ear in mammals