Ch 15: The Origin and History of Life (Exam 4) Flashcards
Identify when current evidence suggests life first arose on Earth
between 4.2 and 3.85 BYA
Explain why clay soils may have been important in the formation of organic macromolecules in the early history of the Earth
-the SHEETLIKE MINERALS in clay form TEMPLATES on which CHEMICAL BUILDING BLOCKS could have linked to build LARGER MOLECULES
-iron pyrite and some other minerals in clay can REALEASE ELECTRONS proving energy to FORM CHEMICAL BONDS
-these minerals may also have ACTED AS CATALYSTS to SPEED UP CHEMICAL REACTIONS
Explain why scientist believe RNA may have been the first genetic material
-RNA stores genetic information and uses it to manufacture proteins
-RNA can also catalyze chemical reactions and duplicate on its own
Explain why the ability of phospholipids to spontaneously form membranes would have been important to the origin of life on Earth
-gave rise to reaction pathways of metabolism, eventually led to respiration, photosynthesis, and thousands of other chemical reactions that support life today
Describe the evidence supporting the idea that the mitochondria and chloroplasts in modern cells originated as independent organisms
-similarities in SIZE, SHAPE, AND MEMBRANE STRUCTURE between them and some types of bacteria
-the DOUBLE MEMBRANE SOUROUNDING THEM
-not assembled in CELLS but instead DIVIDE like bacterial cells
-the contain DNA, RNA, AND RIBOSOMES
-they have a close relationship between mitochondria and PROTEOBACTERIA and between chloroplasts and CYANOBACTERIA
Why is it likely that the mitochondria evolved before chloroplasts?
-because all eukaryotes have a mitochondria but only some have chloroplasts
Explain when in Earths history modern coal deposits were formed and how
-LATE Carboniferous Period and EARLY Permian Period
How: plant debris
-in the period there were dense, swampy forests that produced large deposits of peat, and when the sea covered the swamps, over time peat transformed into coal deposits
Describe the events evidence suggests occurred when the astroid hit Earth near the Yucatan Peninsula at the end of the Cretaceous Period
-it left debris and clay filled crater offshore, and a huge semicircle of sinkholes on shore
-distinktive Iridium layer
-biologists estimate that photosynthesis was almost non existent for 3 years, and debris covered sunlight, and plankton died as well
Physical characteristics shared by all primates
-grasping hands with opposable thumbs
-fingers and toes have flat nails
-eyes set in front of the skull (binocular vision)
-large brain in comparison to body size
What living primates are the most closely related to humans?
Chimpanzees
Explain the advantages of bipedalism
-being able to walk upright on two legs, supports the pelvis, powerful climbing, grasping and carrying
Where did all modern humans originate?
Africa
