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TAXONOMY AND EVOLUTION

TAXONOMY AND EVOLUTION . `THE EARTH IS THOUGHT TO BE NEARLY 4.6 BILLION YEARS OLD. SCIENTISTS BELIEVE THE HETEROTROPH HYPOTHESIS ABOUT FIRST LIFE ON EARTH. OXYGEN WAS ABSENT ON EARLY LIFE BUT CAME TO BE BECAUSE OF THE ACTIONS OF PLANTS.

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TAXONOMY AND EVOLUTION

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  1. TAXONOMY AND EVOLUTION

  2. `THE EARTH IS THOUGHT TO BE NEARLY 4.6 BILLION YEARS OLD. • SCIENTISTS BELIEVE THE HETEROTROPH HYPOTHESIS ABOUT FIRST LIFE ON EARTH. • OXYGEN WAS ABSENT ON EARLY LIFE BUT CAME TO BE BECAUSE OF THE ACTIONS OF PLANTS

  3. LIFE SEEMS TO HAVE BEEN ON THIS EARTH FOR UP TO 3.5 BILLION YEARS. • COACERVATES AND MICRO- SPHERES WERE PRODUCED BY SCIENTIFIC EXPERIMENTS SHOWING HOW LIFE MIGHT HAVE ORIGINATED.

  4. EVOLUTION MAY BE ORGANIC OR INORGANIC. • EVOLUTION APPEARS TO FIT THE MODEL OF PUNCTUATED EQUILIBRIUM. • THE EVOLUTIONARY HISTORY OF AN ORGANISM IS CALLED ITS PHYLOGENY.

  5. EARLY ENERGY ON EARTH PROBABLY CAME FROM LIGHTNING, X-RAYS, AND ULTRA- VIOLET LIGHT. • EARLY GASES ON EARTH WERE PROBABLY HYDROGEN, METHANE, AMMONIA, AND WATER VAPOR.

  6. CONTINENTAL DRIFT EXPLAINS COMMON FOSSILS ON WATER SEPARATED CONTINENTS. • DARWIN AND LAMARCK HAD OPPOSING VIEWS ON EVOLUTION. DARWIN DEVELOPED THE IDEA OF NATURAL SELECTION. LAMARCK DEVELOPED ACQUIRED CHARACTERISTICS.

  7. LAMARCK BELIEVED THAT ACQUIRED CHARACTERISTICS COULD BE PASSED FROM ONE GENERATION TO THE NEXT. • AUGUST WEISMANN DISPROVED THIS BY CUTTING THE TAILS OFF OF MICE FOR 25 GENERATIONS.

  8. PRINCIPLES OF NATURAL SELECTION AS PROPOSED BY DARWIN • THERE IS AN OVERPRODUCTION OF YOUNG IN EACH GENERATION • VARIATIONS EXIST IN THIS LARGE POPULATION

  9. COMPETITION OCCURS WITH THE VARIANTS WITH THE BEST ADAPTATIONS SURVIVING. • THE RESULT IS “SURVIVAL OF THE FITTEST”

  10. THE BIGGEST PROBLEM WITH DARWIN’S THEORY WAS IT DID NOT EXPLAIN A SOURCE OR GENETIC BASIS FOR VARIATIONS.

  11. HOMOLOGOUS STRUCTURES OFTEN GIVE EVIDENCE FOR DIVERGENT EVOLUTION. • ANALOGOUS STRUCTURES OFTEN GIVE EVIDENCE FOR CONVERGENT EVOLUTION. • VESTIGIAL STRUCTURES HAVE NO APPARENT USE AT THE PRESENT.

  12. SPECIES MUST BE ABLE TO REPRODUCE AND PRODUCE FERTILE OFFSPRING IN NATURE. • KINGDOM, PHYLUM, CLASS, ORDER, FAMILY, GENUS, SPECIES. • BINOMIAL NOMENCLATURE INVOLVES USING GENUS AND SPECIES IN AN ORGANISM’S NAME.

  13. PRESENTLY, MOST SCIENTISTS RECOGNIZE SIX KINGDOMS OF LIFE: ARCHAEBACTERIA, EUBACTERIA, PROTISTA, FUNGI, PLANTAE, ANIMALIA • BIOCHEMICAL ANALYSIS IS THE LATEST TOOL USED TO DETERMINE TAXONOMIC RELATIONSHIPS.

  14. HALF-LIFE OF RADIOACTIVE ISOTOPES IS USED TO DETERMINE AGE OF FOSSILS. • A GROUP OF ORGANISMS OF THE SAME SPECIES THAT LIVE IN A CERTAIN AREA IS CALLED A POPULATION.

  15. DEVRIES BELIEVED MUTATIONS WERE THE MAJOR CAUSE OF EVOLUTIONARY CHANGE. • FOSSILS ARE WINDOWS OF PAST LIFE. • SPECIATION IS THE ORIGIN OF NEW SPECIES MOST OFTEN DUE TO GEOGRAPHICAL ISOLATION.

  16. IDEAS TO EXPLAIN VARIATIONS WITHIN A POPULATION • GENETIC RECOMBINATION • GENE FLOW • GENETIC DRIFT • RANDOM MUTATIONS • SPECIATION

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