1. Evol (Class New)

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  • Life is defined partly by two properties: accurate replication and metabolism. Neither property can exist without the other. Self–replicating molecules and a metabolism–like source of the building blocks must have appeared together. How did that happen? The necessary conditions for life may have been met by protobionts, aggregates of abiotically produced molecules surrounded by a membrane or membrane–like structure. Protobionts exhibit some of the properties associated with life, including simple reproduction and metabolism, as well as the maintenance of an internal chemical environment different from that of their surroundings. Laboratory experiments demonstrate that protobionts could have formed spontaneously from abiotically produced organic compounds. For example, small membrane–bounded droplets called liposomes can form when lipids or other organic molecules are added to water.
  • Electron Transport Systems The chemiosmotic mechanism of ATP synthesis, in which a complex set of membrane–bound proteins pass electrons to reducible electron acceptors with the generation of ATP from ADP, is common to all three domains of life—Bacteria, Archaea, and Eukarya. There is strong evidence that this electron transport mechanism actually originated in organisms that lived before the last common ancestor of all present–day life. The earliest of these electron transport systems likely evolved before there was any free oxygen in the environment and before the appearance of photosynthesis; the organisms that used it would have required a plentiful supply of energy–rich compounds such as molecular hydrogen, methane, and hydrogen sulfide. A great challenge facing scientists studying the origin of life is to determine the steps by which this electron transport mechanism originated, and how important early versions of it might have been in the emergence of the first cells. So considerable metabolic diversity among prokaryotes living in various environments had already evolved more than 3 billion years ago. Most subsequent evolution has been more structural than metabolic.
  • Major landmarks in biological evolution. The positions of the stages on the time scale are approximate. Note how the oxygenation of the atmosphere due to cyanobacterial metabolism was a gradual process, occurring over a period of about 2 billion years. Also note that for the bulk of Earth’s history, only microbial life forms existed. Although microfossil evidence is lacking, microchemical evidence for eukaryotic cells goes back as far as 2.7 billion years ago.
  • Diversity of life and periods of mass extinction. The fossil record of terrestrial and marine organisms reveals a general increase in the diversity of organisms over time (red line and right vertical axis). Mass extinctions, represented by peaks in the extinction rate (blue line and left vertical axis) interrupted the buildup of diversity. The extinction rate is the estimated percentage of extant taxonomic families that died out in each period of geologic time. The fossil record chronicles a number of occasions when global environmental changes were so rapid and disruptive that a majority of species were swept away Such mass extinctions are known primarily from the decimation of hard–bodied animals that lived in shallow seas, the organisms for which the fossil record is most complete. Two mass extinctions—the Permian and the Cretaceous—have received the most attention. The Permian mass extinction, which defines the boundary between the Paleozoic and Mesozoic eras, claimed about 96% of marine animal species. Terrestrial life was also affected. For example, 8 out of 27 orders of insects were wiped out. This mass extinction occurred in less than 5 million years, possibly much less—an instant in the context of geologic time. The Cretaceous mass extinction of 65 million years ago, which marks the boundary between the Mesozoic and Cenozoic eras, doomed more than half of all marine species and exterminated many families of terrestrial plants and animals, including most of the dinosaurs.
  • Trauma for Earth and its Cretaceous life. One clue to a possible cause of the Cretaceous mass extinction is a thin layer of clay enriched in iridium that separates sediments from the Mesozoic and Cenozoic eras. Iridium is an element very rare on Earth but common in many of the meteorites and other extraterrestrial objects that occasionally fall to Earth. Walter and Luis Alvarez and their colleagues at the University of California proposed that this clay is fallout from a huge cloud of debris that billowed into the atmosphere when an asteroid or a large comet collided with Earth. This cloud would have blocked sunlight and severely disturbed the global climate for several months. Where did the asteroid or comet hit? Research has focused on the Chicxulub crater. The 65 million–year–old Chicxulub impact crater is located in the Caribbean Sea near the Yucatán Peninsula of Mexico. The horseshoe shape of the crater and the pattern of debris in sedimentary rocks indicate that an asteroid or comet struck at a low angle from the southeast. This artist’s interpretation represents the impact and its immediate effect—a cloud of hot vapor and debris that could have killed most of the plants and animals in North America within hours. About 180 km in diameter, the crater is the right size to have been caused by an object with a diameter of 10 km.
  • The first mammals evolved from a group of mammal-like reptiles called therapsids about 220 million years ago during the Triassic period. The therapsids were among the very few reptiles in a subgroup called "synapsids" that had just barely survived the great dying at the end of the Permian, about 250 million years ago. This massive extinction event was the most severe and dramatic in the history of life on earth and marks the end of the Paleozoic era. More than 90 percent of all marine species were wiped out, including every species of the familiar trilobite; 75 percent of the reptile and amphibian species, including most of the mammal-like reptiles were likewise eliminated.

Transcript

  • 1. Origin of Life “… sparked by just the right combination of physical events & chemical processes…”
  • 2. The History of Life on Earth
  • 3. THE FORMATION OF THE UNIVERSE The universe is 15 billion years old.
  • 4. Earth
    • The Solar system formed about 5 billion years ago
    • Earth formed about 4.5 billion years ago
    • The moon formed soon thereafter
  • 5.
    • The planet’s surface was molten at first
    • It was bombarded by meteors and lightning
    • Volcanoes erupted all over the surface
  • 6. Primordial Atmosphere
    • The atmosphere consisted of gases like H 2 , NH 3 (ammonia), HCN (hydrogen cyanide), Carbon dioxide, Methane and trace amounts of O 2
    • Since there was hardly any O 2 , there was no O 3 (Ozone) layer either
    • UV rays beat down on the planet
    • No O 2 and the planet appeared reddish in color
  • 7. Primordial Earth
  • 8. Extraterrestrial Water?
    • Scientific evidence supports the idea that a hail of comets bombarding the early Earth could have introduced water into early earth’s atmosphere.
    • Comets born near the orbit of Jupiter, are made of water (ice) that matches the isotopic composition of water in Earth's oceans
    • Comets born there might also contain more complex organic molecules, the building blocks of life.
  • 9. Water!
    • As the Earth cooled, much of the atmospheric water condensed and fell as rain. At first it would evaporate immediately, then precipitate again.
    • Eventually it remained on the ground, creating large oceans .
    • Dissolved in the rain was carbon dioxide, which formed carbonate rocks such as limestone and marble.
  • 10. Oceans
    • The CO 2 that was dissolved in the rain was getting reduced to long hydrocarbon chains in the oceans
    • The rain also brought down other inorganic molecules such as ammonia (NH 3 ) that were then converted to organic molecules such as urea and amino acids in the oceans
  • 11. What is Life ?
    • First we have to define LIFE …
      • organized as cells
      • Respond to stimuli
      • Regulate internal processes
        • homeostasis
      • use energy to grow
        • metabolism
      • Develop
        • change & mature within lifetime
      • Reproduce
        • heredity
          • DNA / RNA
        • adaptation & evolution
  • 12.
    • The evolutionary tree of life can be documented with evidence.
    • The Origin of Life on Earth is another story…
    Bacteria Archae- bacteria Animalia Fungi Protista Plantae 4500 4000 3500 3000 2500 2000 500 1500 0 1000 Formation of earth Molten-hot surface of earth becomes cooler Oldest definite fossils of prokaryotes Appearance of oxygen in atmosphere Oldest definite fossils of eukaryotes First multicellular organisms Appearance of animals and land plants Colonization of land by animals Paleozoic Mesozoic Cenozoic Millions of years ago ARCHEAN PRECAMBRIAN PROTEROZOIC
  • 13. The Origin of Life is Hypothesis
    • I. Special Creation
      • Was life created by a supernatural or divine force?
      • not testable
    • II. Extraterrestrial Origin
      • Was the original source of organic (carbon) materials comets & meteorites striking early Earth?
      • testable
    • III. Spontaneous Abiotic Origin
      • Did life evolve spontaneously from inorganic molecules?
      • testable
  • 14. TINTORETTO The Creation of the Animals 1550 I. Intelligent Design
  • 15. Origins of Life “The Scientific Story”
  • 16. II. Panspermia
    • The theory that earth was seeded with primitive life forms from other planets where life actually arose – possibly via a meteor or asteroid from that planet.
    • This merely puts the origin of life backwards to another earth-like planet. It might be possible for very small, radiation resistant spores to travel around the universe under light pressure or for contamination by space travel to occur.
  • 17. III. Spontaneous Abiotic Origin
  • 18. First Attempts at Life
  • 19. Requirements for Prebiotic Chemistry/Earth
    • Little or no free oxygen
      • Oxygen very reactive, would remove electrons needed for reactions
    • Considerable energy
      • Heat, light, electrical energy needed to make/break bonds
      • Vulcanism, sun provided much UV, lightning
    • Chemical ‘building blocks’ to be built into more complex molecules
    • The reactions required time ~ 0.8 billion years to cause life to come about. This is a long time, but not long compared to the life of the Universe (~10-20 billion years)
  • 20. Materials available in the Prebiotic Earth
    • All living things have the same overall chemistry
      • Suggests a common origin
      • However, likely to be multiple similar origins
    • Earth ~ 4.5 billion years old
    • Early atmosphere:
            • CO 2
            • H 2 O vapor
            • CO
            • H 2
            • N 2
            • H 2 S
            • CH 4
            • Virtually no O 2
  • 21. Abiotic Pre-Cellular Protobiont
  • 22. Protobiont
    • is an aggregate of abiotically produced organic molecules surrounded by a membrane or a membrane-like structure
        • Laboratory reactions have produced protobionts , chemical precursors to the formation of cells
        • Have some properties of living cells
        • ‘ Reproduction’ – actually budding
  • 23. Pre-Cellular
    • Building components needed for the
    • first cells
    • Membrane (compartmentalization)
    • Reproduce
  • 24. Replication & Membrane
  • 25. Origin of Cells (Protobionts)
    • Bubbles  separate inside from outside
    •  metabolism & reproduction
  • 26. A. C ompartmentation
    • C ompartmentation (the enveloping of special life reactions) is critical to the formation of living systems
      • Microspheres ( coacervates)
          • Formed from heated mixtures of amino acids
          • Subsequently mixed with salty water
          • Some are excitable
          • Have some catalytic activity
          • Could provide compartmentation required for early prebiotic chemistries
  • 27. Ocean Froth
    • The waves crashing on the shore consisted of bubbles (froth)
    • The “membranes” of the bubble were either made of
      • hydrocarbon chains/lipids
      • Protenoids (chains of amino acids)
  • 28. Protein Microspheres
    • Heat amino acids for 1-2 hours at 170-180 O C
    • Add salty water
    • Mix
    • Gently heat again
    • See microspheres under microscope
  • 29. Microspheres
  • 30. Coacervate growth and division Collection of aggregated polymers Grow by adding new polymers Form a semi-permeable membrane When they get too big they divide Demonstrates how polymers aggregate and act like membranes
  • 31.
    • The current “most accepted “theory of life evolving hypothesizes an RNA world
    • RNA in the early world would have functioned as a self replicating molecule, eventually developing a number of minimal catalytic properties
    RNA B. Molecular Reproduction self-replicates Proteins take over catalysis DNA becomes long term storage and major coding molecule Packaging evolves - RNA codes and catalyses
  • 32.  
  • 33. The RNA World Hypothesis
    • Proposed by Walter Gilbert, mid 1980s
    • Concept of RNA catalyzing critical pre-biotic and early biological reactions
    • RNA would give rise to RNA as an informational molecule
    • RNA would give rise to protein
    • RNA might bind amino acids proteins
    • RNA might give rise to DNA
    • Proteins might take over some functions
    • DNA would take over informational functionality
    • Eventually giving rise to the DNA RNA protein scheme found today
  • 34.  
  • 35. Conditions of a Pre-Biotic Biochemical Evolution
    • A. Primitive ‘Soup’
    • B. The Iron-Sulfur World
    • All living things have the same overall chemistry
      • Suggests a common origin
      • However, likely to be multiple similar origins
    • Earth ~ 4.5 billion years old
    • Early atmosphere:
            • CO 2
            • H 2 O vapor
            • CO
            • H 2
            • N 2
            • H 2 S
            • CH 4
            • Virtually no O 2
  • 36.  
  • 37. Two Basic Models
    • I. Primitive ‘Soup’
    • Haldane and Oparin (~1920s) proposed that life arose from nonliving conditions by means of a series of changes (and increasing complexity) in molecular composition as a result of the reducing, high energy environment that existed on early Earth (between 4.6-3.8 bybp (billion years before present)
    • Proposed the Prebiotic Broth Hypothesis
    • Not tested until 1950s
    • Tested by Stanley Miller and Harold Urey
  • 38. Miller / Urey
    • Created an ancient earth atmosphere in globes
      • H 2 O vapor
      • H 2
      • NH 3
      • CH 4
    • Electrical discharge
    • Heated via mantle in lower chamber
    • Paper chromatography showed that amino acids and other important simple molecules formed
    • Similar experiments have shown that all 20 a.a., lipids, nucleotide bases, and ATP, if phosphate present.
  • 39.
    • Such simple molecules might accumulate in shallow seas
    • Smaller molecules might condense together to form ‘coacervates’ (term by Oparin) to form larger molecules
    • Clays & RNA might be critically important as catalytic surfaces for the formation of such molecules
    • Laboratory experiments show that clays, other rock surfaces are excellent ‘nucleating centers’ for formation of complex organic molecules.
  • 40. Origin of Organic Molecules CH 4 NH 3 H 2 Electrodes discharge sparks (lightning simulation) Water vapor Condensed liquid with complex, organic molecules Condenser Mixture of gases ("primitive atmosphere") Heated water ("ocean") Water
  • 41. II. The Iron-Sulfur World
    • An alternative view says that early life may have formed at hydrothermal vents on the ocean floor
    • Today, hydrothermal vents provide basic materials to support living organisms in environments where there is no light, very little energy, and little other perturbation
    • Ammonia is produced in abundance at such locations, suggesting that it could possibly be built into nucleic acid bases and possibly into amino acids
  • 42. Sea Vents
  • 43. Key Events in Origin of Life
    • Key events in evolutionary history of life on Earth
      • life originated 3.5–4.0 bya
  • 44. 2. Prokaryotes
    • Prokaryotes dominated life on Earth from 3.5–2.0 bya
    3.5 billion year old fossil of bacteria modern bacteria chains of one-celled cyanobacteria
  • 45. Microfossils of Prokaryotes
    • Evident as tiny structures that look very much like cyanobacteria and other modern-day prokaryotes.
          • In rocks formed as long ago as ~3.5 bybp
          • Radiocarbon dating from similar rocks suggest life formed perhaps even 3.8 bybp
    • Stromatolites are layered pillow-like rock structures
      • Layers of prokaryotic cells and sediment
      • Are plentiful in ancient rocks, formed large reefs
      • Found today only in certain limited environments, such as a few hot springs and in Shark Bay, a Western Australian location
  • 46. Stromatolites
    • In the beginning photosynthetic systems may have resembled these stromatolites at Shark Bay, Western Australia
  • 47.  
  • 48. Formation of Aerobes
    • Bacteria which need free oxygen for their survival
    • Aerobes came about after onset of photosynthesis
    • Critical stage; allowed formation of more complex organisms. Producing more energy from glucose than anaerobic metabolism
    • Out-compete anaerobes for populating the Earth
    • Stabilized atmosphere
  • 49. Aerobes: Spirilla Bacteria  
  • 50. Oxygen atmosphere
    • Oxygen begins to accumulate 2.7 bya
      • reducing  oxidizing atmosphere
        • evidence in banded iron in rocks = rusting
        • makes aerobic respiration possible
      • photosynthetic bacteria (blue-green algae)
  • 51. Oxygen
  • 52. Oxygen atmosphere
  • 53. Oxygen
    • Evidence for O 2 production:
    • Banded Iron Formations (BIF)
    • BIF found in ocean sediments red bands are high in Fe 2 O 3 and Fe 3 O 4 (red bands)- forms when reduced iron reacts with O 2
  • 54. 3. First Eukaryotes
    • Development of internal membranes
      • create internal micro-environments
      • advantage : specialization = increase efficiency
        • natural selection !
    infolding of the plasma membrane DNA cell wall plasma membrane Prokaryotic cell Prokaryotic ancestor of eukaryotic cells Eukaryotic cell endoplasmic reticulum (ER) nuclear envelope nucleus plasma membrane ~2 bya
  • 55. Endosymbiosis
    • Evolution of eukaryotes
      • origin of mitochondria
      • engulfed aerobic bacteria, but did not digest them
      • mutually beneficial relationship
        • natural selection !
    Ancestral eukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis
  • 56. Endosymbiosis
    • Evolution of eukaryotes
      • origin of chloroplasts
      • engulfed photosynthetic bacteria, but did not digest them
      • mutually beneficial relationship
        • natural selection !
    mitochondrion chloroplast Eukaryotic cell with chloroplast & mitochondrion Endosymbiosis photosynthetic bacterium Eukaryotic cell with mitochondrion
  • 57.
    • Evidence
      • structural
        • mitochondria & chloroplasts resemble bacterial structure
      • genetic
        • mitochondria & chloroplasts have their own circular DNA, like bacteria
      • functional
        • mitochondria & chloroplasts move freely within the cell
        • mitochondria & chloroplasts reproduce independently from the cell
    Theory of Endosymbiosis
  • 58.  
  • 59. Major landmarks in biological evolution
  • 60. 4. Multicellular: Cambrian explosion
    • Diversification of Animals
      • within 10–20 million years most of the major phyla of animals appear in fossil record
    543 mya
  • 61.  
  • 62.  
  • 63.  
  • 64. Diversity of life & periods of mass extinction Cambrian explosion
  • 65.
    • The Chicxulub impact crater in the Caribbean Sea near the Yucatan Peninsula of Mexico indicates an asteroid or comet struck the earth and changed conditions 65 million years ago
    Cretaceous extinction
  • 66. Early mammal evolution
    • 125 mya mammals began to radiate out & fill niches
  • 67. Carolus Linnaeus 1707-1778
    • Classification system
    • Taxonomic groups of related organisms
    • Binomial nomenclature (two names)
    • Example: Homo sapiens
  • 68. Seven classification groups of living things
    • Kingdom
    • Phylum
    • Class
    • Order
    • Family
    • Genus
    • Species
  • 69. Questions
    • What are the seven classification groups?
    • K ings P lay C ards O n
    • F at G reen S tools
  • 70.  
  • 71. Plant Kingdom Diversity
    • The plant kingdom has within it 4 major groups:
    • Bryophytes (mosses & liverworts)
    • Filicinophytes (Ferns)
    • Coniferophytes (Conifers & Pines)
    • Angiospermophytes ( Flowering Plants)
  • 72. Bryophytes
    • Small terrestrial plants
    • Do not have true roots, stems or leaves but they must have structures resembling them
    • Leaf-like structures are often arranged in a spiral
    • Usually have live in clusters which act like sponges holding water
    • No cuticle
    • Reproductive structures are called sporangium which is on long stalks with capsules on end.
  • 73. Filicinophytes
    • Ferns have divided leaves, roots and non woody stems.
    • They reproduce forming sporangia (Sori) on the underside of the leaf surface.
    • Like the Bryophytes they have a world wide distribution however the largest of the species are to be found growing in the tropics in excess of 20m.
  • 74.  
  • 75. Coniferophytes
    • trees, shrubs, woody stems, waxy narrow needle like leaves. vascular system.
    • Reproductive Structures (male) non motile gametes often with air bladders for water/ air dispersal. macrosporophylls (female) ovule on cone scale
  • 76. Angiospermophytes
    • roots, stems and leaves. complex tissue structures, vascular bundles (xylem/ phloem ), waxy cuticle,
    • annual or perennial up to 100m
    • Reproductive Structures ovules in an enclosed carple structure.
    • pollen grains produced from anthers
    • variety of pollen transfers vectors
    • Group is divided into the Monocotyledons and the Dicotyledons
  • 77. Organisms Animals Plants Monera Protista Fungi Jellyfish, worms, arthropods, molluscs, echinoderms, amphibians, fish, reptiles, birds and mammals. Seed bearing plants and non-seed bearing plants Bacteria and primitive algae Single-celled organisms Moulds, mushrooms and toadstools
  • 78. Animals Vertebrates Mammals Fish Reptiles Amphibians Birds Invertebrates Flatworms True worms Molluscs Echinoderms Cnidarians Arthropods
  • 79. Animal phyla
    • There many phyla from the animal Kingdom, we
    • will focus on 6 all invertebrates. This group has
    • common feature, the lack of a notochord (spinal
    • cord ). This group is classified according to
    • these characteristics:
    • Heterotrophic
    • • No cell walls
    • • No vacuoles
    • • No chlorophyll
    • • Store glycogen
  • 80. Animals Vertebrates Invertebrates
  • 81.
    • The six phyla are classified according to
    • Different features such as:
        • number of layers in the body plant
        • opening for mouth and anus
        • method of support
        • Phylogenic studies (evolutionary relationship) relies on more genetic studies to support the modern classification of these groups.
  • 82. Phylum: Porifera (sponges)
    • • No body layers rather there is an aggregate of different cell types.
    • Support is from either silica or calcium based spicules which link together to provide some support.
    • Body plan is built around water canals that circulate nutrient through the sponge for ingestion by specialized cells.
    • There is no mouth or anus
  • 83. Phylum: Cnidaria (Jelly fish, Sea anemones, Corals)
    • • These have 2 layers in the body plan.
    • • There is a radial symmetry.
    • • Jelly fish are mobile organisms. Sea anemones are sessile organisms.
    • • Single entrance that serves the the cavity that functions of the circulation of respiratory gases and nutrient. These organisms are secondary consumers and posses stinging cells with toxins called nematocysts to disable prey.
    • • Corals secrete a CaCO 3 skeleton
  • 84. Some Cnidaria can grow to over 120 feet long
  • 85. Phylum: Pla ty helminthes (flatworms)
    • 3 layers in the body plan.
    • One entrance to 'gut' which can have many folds to increase surface area.
    • Largely parasitic includes flukes
  • 86.   Phylum: Annelida (segment worms)
    • 3 layers to the body plan / bilateral symmetry
    • Body divided into ringed segments with some specialization of segments
    • Mouth connected via gut to a separate anus.
    • Skin surface used for gas exchange.
    • Many marine forms but also terrestrial species usually soil burrowing
  • 87. Phylum: Mollusca (Snails, slugs and octopus)
    • Bilateral symmetry with significant modification.
    • • An extraordinarily varied group which has developed some radically divergence from other groups.
    • • Phylogenic studies place them closer to annelids than other groups.
  • 88. Body plan has three major features:
    • • Foot, a muscular structure used for movement and burrowing.
    • • Central visceral mass containing all the organ structures (separate mouth and anus)
    • • Mantle a folded membrane structure that can surround other tissues and create a cavity containing a gill.
    • • The mantle frequently secretes a calcareous shell.
  • 89. Phylum: Arthropoda (Insects, Crustaceans, Spiders, Scorpions, Millipedes)
    • • 3 layer body plant with bilateral symmetry.
    • • Hard exoskeleton composed of chitin.
    • • Jointed body segments.
    • • Jointed appendages.
    • • Some flying organisms in the class Insecta. •Separate mouth and anus.
  • 90. Insects
  • 91. Crustaceans
  • 92. Spiders
  • 93. Scorpions
  • 94. Millipedes
  • 95. Dichotomous keys
  • 96. Design Principles:
    • Each question divides the group of organisms into two smaller groups based on a pair of alternative characteristics
    • • Subsequent groups may focus on more minor detail
    • • In most cases the characteristic will be readily observed or measurable
    • • It is better to choose characteristics that are uninfluenced by environmental variation
    • • Shape and number are often good characteristics on which to base alternative pairings
    • • A complete key will have each type of organism being classified separated with a final identifying name.
  • 97. Terminology
    • Classification
      • Assigning organisms to different categories based on their relationship
    • Taxonomy
      • The science of naming organisms
    • Systematics
      • Determining evolutionary relationships of organisms
    • Phylogeny
      • Evolutionary history
  • 98. Cladogram
    • Evolutionary relationship of a group of organisms
    • Each clad (group) share something in common
    • Ancestral traits are the oldest
    • Derived traits evolved later
  • 99. Cladogram for Transportation
    • Wheels are the most ancestral
    • Wings are the most derived
  • 100. Construct a Cladogram
  • 101.
    • Four limbs
    • Fur
    • Lost tail
    Gorilla
  • 102. Tiger
    • Four limbs
    • Fur
    • Tail
  • 103. Lizard
    • Four limbs
    • Tail
  • 104. Fish
    • Tail
  • 105. Chimpanzee
    • Four limbs
    • Fur
    • Lost tail
  • 106. Clad With 4 Limbs
  • 107. Clad With Fur
  • 108. Clad With No Tail
  • 109. Characteristics for Constructing Cladogram
    • Tail is the most ancestral
    • Four limbs is the oldest derived trait
    • Fur is a later derived trait
    • Loss of tail is the most derived trait
  • 110. Tiger Lizard Fish Gorilla Chimpanzee Four Limbs Fur Tail Lost