Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Evolution does not imply fish evolved into birds but rather that there was a common ancestor to both fish and birds that gave rise through millions of small steps over hundreds of millions of years to many different species including the fish and birds we see today. In the tree on the right the last common ancestor to fish and birds is marked . At this point the tetrapod line split off from the fishes as evidenced by such fossils as Tiktaalik and this new line led eventually to all the major tetrapod groups amphibians reptiles including birds and mammals. It takes a long time for new groups to emerge but evolution has been at work for four billion years. To put this in perspective if you took only one step each day but kept walking for four billion years you would travel 829545454 miles more than four times to the sun and back. Evolution works the same way millions of small stepswith many stops and starts over enormous periods of time. T H E T R E E O F LIF E 42 Bacteria Algae Ferns NonfloweringSeedPlants FloweringSeedPlants Mosses Fungi Sponges Flatworms SegmentedWorms Spiders Mollusks Insects