genomes to ecosystems lecture 5- speciation, extinction and radiation Flashcards
what are allopartic events?
an external barrier separates populations which then diverge genetically
what is a sympatric event?
there is no geographical barrier and populations may differ in habitat, behaviour or adaptation.
assortave mating may lead to genetic divergence
what does random species look like?
there are 3 branches of species and 3 branches of species so there equal
what is an allopatric founder event?
small populations become isolated and therefore rapid evolution due to non-random sample of genes, different environment etc
what are the causes of adaptive radiations?
-key innovations
-environmental changes eg new habitats
-ecological changes eg new opportunities
what does non-random speciation look like?
there are 5 species batches then one species on the other due to mutations being more common
what are facts about bony fish?
-single most species rich vertebrate group
-third whole genome disruption
-buoyancy using swim bladder
-innovations in jaw structure (protruding upper jaws and secondary jaws)
what is a kinetic skull ?
mammalian skulls are mostly fused bone, lower jaw moves and many bony fish skulls have multiple moving parts
what is Cambrian explosion?
-nearly all major animal phyla appear in Cambrian rocks (545-525 million years ago)
-many weird and wonderful creatures appear suddenly in the fossil record
what are pharyngeal jaws?
-second set of jaws contained within fishes throat
-distinct from the primary, oral jaws
-modified gill arches
-to manipulate and help with swallowing prey
what happens to isolated giants and dwarfs?
giant animals evolve smaller dwarfs and small animals evolve large giants
what cause the explosion?
-environmental changes
-developmental changes
-ecological changes
when were mammoths surviving?
-most megafuana extinct by 12,000 years bp
-mammoths still on St Paul 6,500 years bp
-great pyramid of Giza 4,600 bp
what are environmental changes?
-increase in oxygen levels –> may have finally reached level to support large animals
-snowball earth –>hypothesis that earth iced over before 650 mya
what are developmental explanations (HOX genes)?
regulate development of segmentation in animals
what are ecological changes?
-evolution of eyes leading to predation
-arms race between predators and prey
what caused the extinction of megafauna?
- Human hunting of megaherbivores (causing extinction of predators as well)
- Climate change (end of ice age)
- Disease (from humans and/or associated animals)
- Second-order predation (humans kill predators, prey overpopulation then collapse)
how much dna in eurasians come from neanderthals?
1-4%
what is de-extinction?
1- dna extracted from mammoth found in permafrost
2- identify genes which separate them from elephants such as the coat they have
3- splice the mammoth gene into the genome of an elephant embryo
4- grow the mammoth embryo within an artificial womb
5- mammoth elephant hybrid is born with a number of mammoth traits
