3 SECTION #1B:Unicellular: Single–cell; 1 cell Ex: Bacteria Multicellular: 2 or more cells Ex: Algae Mammals:
4 Mass Extinction When a large # of species DIE out suddenly 2 Major Ones:1) Permian- 250 million yrs ago (end of Paleozoic Era) 90% of OCEAN LIFE died out ….the LARGEST MASS EXTINCTION!!2) Cretaceous - 65 million yrs ago (end of Mesozoic Era) Dinosaurs became extinct
5 Section #2:BIOLOGICAL EVOLUTION – Process through which SPECIES CHANGE over time due to a CHANGE IN GENETIC MATERIAL that is passed through GENERATIONS.
7 EARLY IDEAS: LAMARCK: (p 18B) French Animals ACQUIRED traits during their lifetime and passed them on to their OFFSPRINGEX:DARWIN: (p 19B)BritishNATURAL SELECTION – members of a species that are BEST SUITED to the ENVIRONMENT (nature) will survive & reproduce. SURVIVAL of the FITTEST!4 principles to supportEX:Beaks of Finches(Galapagos Islands)
11 Voyage of Beagle Dates: February 12th, 1831 Captain: Charles Darwin Ship: H.M.S. BeagleDestination: Voyage around the world.Findings: evidence to propose a revolutionary hypothesis about how life changes over time
15 VARIATIONThere are NATURALLY occurring differences in TRAITS due to different GENETIC MATERIALS or due to MUTATIONS-this is the PHENOTYPE of the organism (HOW it LOOKS on the outside)Variations get “passed on”EX: BROWN vs BLUE eyes
16 MORE VARIATION… EX: NEMO had a short fin NO 2 zebras have the same STRIPE pattern
18 DARWIN’S PRINCIPLES (CONT.) ADAPTATION: INHERITED TRAIT that gives an organism an “A”dvantage” in its environment over other members. EX: Move faster (cheetah); blend in (lions); camouflage (chameleon); shape of tail fin (fish)SELECTION: Organisms with an ADAPTATION will SURVIVE & REPRODUCE and PASS ON the ADAPTATION “SURVIVAL OF THE FITTEST!”
19 ADAPTATION“Inherited” trait that gives an organism an ADVANTAGE in its particular environment over other members of the groupEX:- Fish with curved tail swim faster (speed)- White fur rabbits blend in to snow better in arctic climates (camouflage)- Birds with stronger beaks can get food better (feeding)Bears can hibernate when their food source is scarceBeetle with horns can fight off beetle without horns (defense)
20 Adaptation ActivityWill YOU survive?????I Will Survive!
24 Adaptation: non winged human jumps from winged vehicle And……FLIES … WHOOP WHOOP!!
25 SPECIATION & ISOLATION Evolution of a NEW SPECIES from an old species, due to ENVIRONMENTAL CHANGE“SPECIATION is due to ISOLATION!!!2 populations of SAME SPECIES separated; can’t reproduce; differing mutations occur; each evolves – 2 DIFFERENT SPECIES“ISOLATION causes SPECIATION”A1A2
26 Evidence for Evolution: 1) Fossil Record2) Biological Evidence:A.)Homologous Structures = similar structure with different function, means common ancestry (Ex: forelimbs)B.)Analogous Structures = similar function, but not from common ancestorC)Vestigial Organ = organ or structure used in an ancestor, still present but not used in the evolved organism(Ex: leg bones in whales, appendix in humans)
32 3)GENETIC/DEVELOPMENTAL EVIDENCE A) Similarities in embryologyB)Matching gene/DNA sequences
33 Evidence of Evolution: Molecular Biology Molecular Biology - the genetic structure of an organismThe key to understanding how traits are passed from one generation to the next is DNA analysisScientists can tell how closely related organisms are by studying their DNAThere does not have that much of a difference in a gene sequence to be a different organism!
34 Evidence of Evolution: Embryology Embryology – shows similar developmental stages amongst different species
42 Which Brings Us Back To… Natural Selection Or “Survival of the Fittest” What does “Survival of the Fittest” really mean? In the next few scenarios,describethe phenotype that would most likely be “selected” to survive…
44 Survival of the Fittest Scenario 1: DroughtThere has been a drought and all of the grass has dries up and dies first, but the leaves on bushes and trees are slower to die…who survives the longest?Animals with short legs but long necksAnimals with long legs, but short necksAnimals with both long legs and long necksAnimals with both short legs and short necks
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