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• 13.1-13.2 Earth’s history has been unveiled by founding scientists applying critical thinking. Key evidence for past life is preserved in fossils.
• 13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
• 13.6-13.10 The Geologic Timescale is a calendar of events in Earth’s history, largely marked by biota (or absence of) that lived at different times.
Learning Objectives: You will have a basic knowledge of how fossils preserve evidence for past life, the proven process of evolution, and the dominant events in Earth’s history.
13-1 Earth’s history has been unveiled by scientists applying the tools of critical thinking.Nicholas Steno (1638-1686)• Father of geology and stratigraphy (and the
right hand shaka)
• First to suggest that fossils had once been living organisms
• Developed the stratigraphic principles of....Exercise 1:
• Naturalist aboard HMS Beagle • Studied Principles of Geology (by Charles Lyell)• Wrote On the Origin of Species by Means of Natural
Selection • Credited with the theory of evolution
13-1 Earth’s history has been unveiled by scientists applying the tools of critical thinking.
No Charles. For the 4th time, its an
IGUANA, there are no geckos here yet!
Darwin observed that all living things reproduce rapidly, and yet no one group of organisms had been able to overwhelm Earth’s surface. This led Darwin to conclude that not all individuals in a generation will survive.
But, which survive and which do not?
Nature must select those with the most favorable variations. Darwin proposed that evolution occurred by natural selection.
• 13.1-13.2 Earth’s history has been unveiled by founding scientists applying critical thinking. Key evidence for past life is preserved in fossils.
• 13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
• 13.6-13.10 The Geologic Timescale is a calendar of events in Earth’s history, largely marked by biota (or absence of) that lived at different times.
Learning Objectives: You will have a basic knowledge of how fossils preserve evidence for past life, the proven process of evolution, and the dominant events in Earth’s history.
process by which favorable traits that are heritable (passed on to
offspring) become more common in successive generations...”
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
• It is the incremental adaptation to environmental or community “pressures, whatever they may be.
• “Primitive” indicates prior and different not inferior (or superior) in general.
• “Evolved” indicates an adaptation to more recent conditions, not superior (or inferior) in general.
Genetic Mutations(random changes to DNA)
Genetic Variation(differences in inherited traits)
• Early proponents of Darwin’s theory had trouble convincing colleagues that evolution was at work. Evolution can take generations to reveal changes, making it difficult to observe as it is occurring.
• Fossils provide clues to understanding this process:(1) Phylogeny (forward progression of physical traits)(2) Homologous (similar) structures(3) Vestigial (remnant) structures(4) Embryology (similarities among embryos)
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
Fossils provide clues to understanding this process:(1) Phylogeny (forward progression of physical traits)(2) Homologous (similar) structures(3) Vestigial (remnant) structures(4) Embryology (similarities among embryos)
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
FIGURE 13.8 The phylogeny of the horse family shows consistentchanges in the lower leg area, the development of molars designed for chewing tough grasses, and an increase in body size and strength.
Fossils provide clues to understanding this process:(1) Phylogeny (forward progression of physical traits)(2) Homologous (similar) structures(3) Vestigial (remnant) structures(4) Embryology (similarities among embryos)
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
FIGURE 13.9 The limbs of various animals are modified for different functions. Notice that individual bones have been modified in different ways to accomplish specific types of tasks (grasping, walking, flying, and paddling). All limbs possess the same basic set of bones in the same order.
Fossils provide clues to understanding this process:(1) Phylogeny (forward progression of physical traits)(2) Homologous (similar) structures(3) Vestigial (remnant) structures(4) Embryology (similarities among embryos)
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
FIGURE 13.10 (a) Whales possess a vestigial pelvis & femur originally designed for walking. Proof that modern whales have evolved from walking ancestors was found in 1994 in the form of a fossil whale that had flippers for front legs and long hind limbs with elongate toes for webbed feet. (b) Boa constrictors also have vestiges of legs.
Fossils provide clues to understanding this process:(1) Phylogeny (forward progression of physical traits)(2) Homologous (similar) structures(3) Vestigial (remnant) structures(4) Embryology (similarities among embryos)
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
FIGURE 13.11 Many animals display remarkably similar
(5) Molecular genetics provide evidence for evolution and allow us to define evolutionary relationships among all life.
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
HIV evolves new drug-resistant strains. It hijacks a cell’s machinery to duplicate itself; the new virus particles (yellow) then burst from cell membrane (blue), killing it.
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
Flu viruses evolve very quickly: that’s why a new flu vaccine is introduced every year
Anti-biotic resistant bacteria on the rise
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
Exercise 2: What are the 5 forms of evidence for evolution?
Mass extinctions: Large numbers of species permanently die out within a very short period of time.
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
Hypothesized causes include meteor impacts and massive flood volcanism, both of which would alter global climate.
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
440-450 Mya: Shortly after
life immerged onto land
360-375 Mya
251 Mya, most catastrophic
200 Mya, may have been caused by massive volcanism
65 Myr, killed the dinosaurs,
possibly caused by Chicxulub
impact
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
440-450 Mya: Shortly after
life immerged onto land
360-375 Mya
251 Mya, most catastrophic
200 Mya, may have been caused by massive volcanism
65 Myr, killed the dinosaurs,
possibly caused by Chicxulub
impact
??
13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
Exercise 3: How many major mass extinctions have their been? Which one killed the dinosaurs?
• 13.1-13.2 Earth’s history has been unveiled by founding scientists applying critical thinking. Key evidence for past life is preserved in fossils.
• 13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
• 13.6-13.10 The Geologic Timescale is a calendar of events in Earth’s history, largely marked by biota (or absence of) that lived at different times.
Learning Objectives: You will have a basic knowledge of how fossils preserve evidence for past life, the proven process of evolution, and the dominant events in Earth’s history.
• 13.1-13.2 Earth’s history has been unveiled by founding scientists applying critical thinking. Key evidence for past life is preserved in fossils.
• 13.3-13.5 Evolution is shown by several lines of evidence, including modern molecular biology. Five global mass extinctions have altered the course of evolution.
• 13.6-13.10 The Geologic Timescale is a calendar of events in Earth’s history, largely marked by biota (or absence of) that lived at different times.
Learning Objectives: You will have a basic knowledge of how fossils preserve evidence for past life, the proven process of evolution, and the dominant events in Earth’s history.