Week 4 Notes
Week 4 Notes Geo 003
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This 3 page Class Notes was uploaded by Yasmine Gohar on Thursday April 21, 2016. The Class Notes belongs to Geo 003 at University of California Riverside taught by Prof Mary in Spring 2016. Since its upload, it has received 16 views. For similar materials see History in the Headlines of Life in Geology at University of California Riverside.
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Date Created: 04/21/16
Lab 3: Environments- - Using fossils to tell about past environments: - Cross Stratification- sand dunes buried get the horizontal and vertical lines that tell us about the previous environment - Energy- high energy (beach, bad for fossil preservation); low energy (deep sea, finest grains and best preservation) - HARD AND FAST FOR BEST PRESERVATION - Crynoids break apart in hours or days - In vs. epi-faunal preservation - Nektic vs. Benthic - Shape (streamline or circular) - Thickness- weight of organisms in water vs. in air o Things in water can be super heavy and still float (things in water can build shells and what not without a big use of energy) due to the high density of the water o Shells on land will be thinner and lighter than those in the water (snail vs. turtle) Lecture: Life and Times in the Precambrian - Now going into the Phanerozoic -Precambrian fossil record -body plans -protosome and deutrostome - - First evidence of life- fossil filamentous bacteria nearly 3.5 billion years old (oldest fossils known) First multicellular animals- 565 million years ago - Appear earlier but come into abundance 565 mya Three grades of Animals- Body Plants: - Proifera: no/single tissue, no symmetry (sponges) o Most primitive multicellular animals Simplest metazoans No Gastrulation Sessile filter feeders ( colonial or solitary) Bodies supported by spicules ( made of either silica or calcite) Some are “woven like a net” some planar lamination Choanoflagellates—closest relative to the metazoans Protista: collar cells similar to the collar cells in sponges - Cnidarian: two tissues (diploblastic); radial symmetry (jellyfish, corals, anemones) o Gasturlation: produces 2 tissue layers Endoderm: Forms gut and digestive tissue o No through gut Where food comes in, waste comes out Ectoderm: Outer body lining Contains stinging cells—nematocysts—many are toxic o Radial Symmetry o Alteration of Generations: 2 life stages: Polyp: benthic, sessile, colonial or solitary o Reproduces asexually or sexually Medusa: pelagic; planktonic o Reproduces sexually o Major reef builders - Biltaterians: three tissues (triploblastic) bilateral symmetry (vertebrates, molluscs, arthropods, insects… etc) o Single plane of symmetry (bilateral symmetry) o Triploblastic: Endoderm: inner body lining and THROUGH gut and digestive tisssues and organs Ectoderm: Protective outer body lining, CNS (central nervous system) Mesoderm: Middle tissue: derivatives include circulatory system and muscles Coelom- fluid filled body cavity—cushions organs Creates environment for organs to grow independent of body o *****Acts as a Hydrostatic skeleton provides a structure for muscles to work against, which helps locomotion o two major groups based on embryogenesis: Protosomes: During gastrulation the mouth forms first These include the arthropods, brachiopods, bryozoans Deuterostomes During gastrulation Anus forms first o Include vertebrates, starfish o What is a tissue? Generic Def: group of similar specialized cells organized into a functional unit Similar cells that form together to create a tissue o Three main kinds: Ectoderm Endoderm Mesoderm “Germ layers” o Where do the tissues come from? Gastrulation: During embryogenesis cells differentiate into various tissues (germ layers) Building Animals: 2 types of genes: 1- Regulatory genes: a. Decided what piece should be built where and when i. Hox genes- regulatory genes that identify with specific regions of the body 1. Conservative: hox genes in a fly will work in a mouse a. Directly reflects evolutionary relationships 2- Structural genes a. Do the actual building - Regulatory genes are the architects - Structural genes are the carpenters Ediacarans: - First macroscopic ‘animals’ on the planet o Bilaterians? First complex ecosystem (Precambrian radiation) o Occur globally o Are abundant when they occur o About 40 different genera o Big and small o Morphologically very diverse o Soft-bodies Guest Speaker: