9 91 universit dottawa university of ottawa early

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Unformatted text preview: data on this period and the evidence Doushantou fossils 580-542 Ma evidence of glaciation even if rocks are in tropical zone of the planet - have drifted from continent to different place in the world - suggestion that earth is a frozen solid snowball -possibly first time land masses rise out of the ocean - erosion is present, mineral and sediments put into theocean that werent present before/ mineral pul carbon dioxyde out of the air/ removing the green house gasses/ earth cools - land mass in the middle does not absorb heat. -Loss of capaity of the planet to absorb sun/cooling - Cooling= ice sheats at north and south pole/ oceans become shallower/ continental shell is exposed. -Evidence of cyanobacteria - this is unstoppable./ CO2 levels drop/ tipping point where everything freezes over - planet is frozen./ earth is ready to begin multicellula? 2 sets of fossils slightly predating the Cambrian explosion - edicara and doushantou - about 550 million yrs ago - arund when the earth freezes -doushantou- appear to be early embryos (evidence of multicellular life)? - ocean becomes so hostile to life that this evolution sops? BIO1130 Organismal Biology Université d’Ottawa / University of Ottawa 92 2:25 PM see previous slides Doushantuo fossils 590-565 Ma BIO1130 Organismal Biology Université d’Ottawa / University of Ottawa BIO1130 Organismal Biology 93 2:25 PM Page 31 Phanerozic - Paleozoic oldest protoanimals -some distant relative -provide us with view of our own begginings - made up of very small modules - mistaken point assemblage- prior to and around time of snowball earth there is presence of life - coming out of snowball earth/ through volcanic activity and ice sheat and outgassings, greenhouse gases come back and the cambrian explosion hits. - multicellular life starts and is stalled Ediacaran fossils 580-542 Ma (Mistaken point NFLD) Protoanimals of Mistaken point Australian footprints BIO1130 Organismal Biology 94 Université d’Ottawa / University of Ottawa 2:25 PM Cambrian burrowers Advantages – Feeding – Anchorage – Protection Ediacaran benthic zone Cambrian benthic zone BIO1130 Organismal Biology Université d’Ottawa / University of Ottawa 95 2:25 PM organisms may break through matte of algal material previously impenetrable - mollusc use radula to make openings and spaces that burrowers may use to get to sediments -advantage because organic material may be reached - results in a quick diversification of animals (burrowers) - advantage of protection is also present - sit in burrows and filter feed. - organisms learn how to biologically preticipatte calcium out of solution and use as a protective armor( cretaceous, etc.) - organisms begin to bulk up in size predators are overcome with pressure to do the same(called arm's race) arms race for bulk and mass/ new food sources/ new predators and prey. speciation and new phylum= explosion in diversity Homeotic genes Figure 34.31 BIO1130 Organismal Biology Université d’Ottawa / University of Ottawa BIO1130 Organismal Biology 96 2:25 PM genes that convey pattern in organismsegg about to undego development/ how to determine which parts to develop to be successful. - how does cell recognize it is part of posterior or anterior part of the protein. - trascription factors fold genes to make different types of meesages -in embryo is a different type of message - controlling factor in gearing production of different types of protein - protein is being factored and radiant through cell - cell in high environment positioned and folded in order to make anterior end fators - on opposite end Page 32 - gradient that tells the cell what to do with genome called homeotic genes how identical cells in embryo that make up differenctiation in eukaryotes Phanerozic - Paleozoic set of genees first found in fruit fly Homeotic genes Hox genes Fruit fly embryo Figure 34.34 as genes are expressed they create a pattern anterior signalling system is the same in mouse and fruit fly/ series of experiments- fucking up the embryo composition legs where antennae are. gradient of info in embryo that signaled cells as to what they are suposed to be this is how we end up with pattern. Distinct homolgy with every animal Mouse embryo 97 2:25 PM Homeotic genes Hox genes Normal fruit fly Homeotic mutant Haltere BIO1130 Organismal Biology Figure 34-33 Université d’Ottawa / University of Ottawa 98 2:25 PM Homeotic genes Hox genes 99 2:25 PM BIO1130 Organismal Biology Different homologous genes within each family set of patterning genes that control the pattern of shape an (GO OVER LECTURE) these are hox genes suspected to have occured and develloped right around cambrian - duplication of genes - how variation occurs in eukaryotes - increase in genome numbers allowes predictable pattern no geneti coding before cambrian/ not as much variatin. - molecular clocks applied to the genes older than the cambrian-> goes back into multiple life forms before the cambrian - planet warms up/ biological complexity explodes. Page 33 Phanerozic - Paleozoic very large percentage of organisms is lost biggest mass extinction= losing more than 50% of what was present - continental shell exposed- survivorrs coming out form time Extinction intensity Mass extinctions Millions of years ago BIO1130 Organismal Biology Figure 27-14 100 Université d’Ottawa / University of Ottawa BIO1130 Organismal Biology 2:25 PM Figure 27-8 101 Université d’Ottawa / University of Ottawa 2:25 PM Extinction intensity Mass extinctions Millions of years ago BIO1130 Organismal Biology Figure 27-14 Université d’Ottawa / University of Ottawa BIO1130 Organismal Biology 102 2:25 PM Page 34 Phanerozic - Paleozoic ! Animal innovations (Symplesiomorphies) 1. Pharyngeal gill slits Dorsal hollow nerve cord 2. Endostyle Post-anal tail and tadpole swimming 1 2 Porifera Placozoa Cnidaria Ctenophora Platyhelminthes Gastrotricha Gnathostomulida Cycliophora Rotifera Annelida Mollusca Sipuncula Nemertea Bryozoa Brachiopoda Phoronida Arthropoda Onychophora Tardigrada Nematomorpha Nematoda Priapulida Kinorhyncha Loricifera Echinodermata Hemichordata Chordata BIO1130 Organismal Biology lateral ondulations - all it looks like at this period of time in siluian and devonian they will develop vertebrae and become vertebrate fishes - become precursors of all land plants - loss of alarge ammount of organisms - beggining of continental fusion- continental shelfs for diversity to occur. very first vertebrates Page 35...
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