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“… it is highly important for us to gain some notion, however imperfect, of the lapse of years.” Charles Darwin: On the Origin of Species 1859 Chapter 9: On the Imperfection of the Geological Record. Patterns in Time. DEEP TIME. Experience DEEP TIME… with its….
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“… it is highly important for us to gain some notion, however imperfect, of the lapse of years.” Charles Darwin: On the Origin of Species 1859Chapter 9: On the Imperfection of the Geological Record
Experience DEEP TIME…with its… PATTERNS of FOSSIL AGES and its PATTERNS of staggered ORIGINS
FOSSILS... Trilobites Ferns Brachiopods
Ammonites Achaeopteryx Seymouria
When did they live? Long ago? How long? All at once? When?
Animals of the Past: Patterns in the Fossil Record Notice the origins… Notice the time…
What’s “65 mya” ? 65 millions of years ago How much is 65 mya? How much is ONE mya? How many human lifetimes is this? LET’S WORK IT OUT….
If each day is one inch long… 1” … how long is a week? … a month? … a year?
If ONE YEAR is 365 inches, how many feet is that? 365/12 = ~30 feet - or 10 YARDS 10 x 10 Yards = ? 100 Yards So… What’s 100 yards? Right! A FOOTBALL FIELD! Therefore, if 1 day = 1 inch, 10 years = 1 football field!
IF… 1 day = 1 inch, 10 years = 1 football field! And a million years would be… 5,700 miles! Can you VISUALIZE THAT?
So, let’s try a different scale… Not easily… Let’s take 10years of your life,and reduce it to 1 millimeter!
If you do this, 1 football field would equal 1 million years!
…and hundreds of millions of yearsare much easier to visualize Let’s try this…
You can plot 100s of millions of years on a map of your local area… For example, 500 mya would only be about 30 miles away
…or plot billions of years within your state the past 500 million years the past 4.6 billion years
All of this in fairly familiar territory… When you shrink 10 years of your lifeinto one tiny millimeter…
So 500 million years would be about 30 miles away… And 50 million years would be about 3 miles away
LET’S DO IT!Calculating distances for mya: • If 1 mm = 10 yrs, then 1 fbf = 1 mya • x1000: 1000 mm (= 1 meter) = 10,000 yrs • x100:100meters = 1,000,000 yrs = 1 mya • 1 meter ≈ 1 yard, so… • 100m ≈ 100 yards = 1 football field = 1 mya • x10:10 fbf = 1000 meters = 1 km = 10 mya • 10 mya= 1 km = 0.6 mile
Calculating distances for mya…Continued… • 10 mya= 1 km = 0.6 mile • So100 mya = 6 miles so… 6 miles= 1 100 mya • So… Desired Distance=6 miles for Desired Time 100 mya • SO… DD = DT x 0.06 • Example: If DT is 65 mya: DD = 65 x 0.06DD = 3.9 miles • OR… Use the table provided!
Geolgical Time Scale FBF km mi mya mi cm
5 mi 1.9 cm Finding MAP Distance on Map Find the map scale: Measure its length: So, on this map, 1.9 cm = 5 miles Map Distance=1.9 cmDesired Dist. 5 mi OR… MD = DD x 0.38 Example: If Desired Distance is 13.2 mi., MD = 13.2 x 0.38 = 5.02 cm
Or… Check the Geolgical Time Scale This Map Scale: 5 mi = 1.9 cm FBF km mi mya mi cm
And plot that Map Distance as the radius of a circle or arc centered from your school…13.2 miles ≈ 5 cm (for 220 mya) ordistance from SJSUto Cupertino!
Now, when you see the 10s of millions of years that separate the originsof the different classes of vertebrates,
In order to get more familiar with those vertebrate classes, and when their first fossils appeared,You may be asked to make your very own “Chronology of Fossil Vertebrates” Your Own Vertebrate Timeline
You will use this chart showing basic vertebrate traits for all the groups… PLUS a set of distinctnew modificationsNew Traits, added when each new group appears…
Chronology of Fossil Vertebrates On this timeline grid, mark when the first fossils for each class appeared, starting at the lower left, and shifting to the right with each class -as shown here…
Chronology of Fossil Vertebrates Now label each of those first fossils, along with their additional traits Notice how many millions of years between the beginnings of each group…
Chronology of Fossil Vertebrates Then draw vertical lines from each “first fossil” up to the top line that represents “NOW” (except for the Pre-mammals, that became extinct about 60 mya), and LABEL EACH.
ADDED FEATURES: You could vary the thickness of each line to show relative diversity in each group through time, and/or, you could find and add pictures of typical members of each group. Or, make a larger version - for the wall
Notice, by the way, that each class has the same traits as the previous class… PLUS a set of distinctnew modificationsthat are unique to each new class…
We ALSO find many fossils showing gradual transitions from class to class… fish to amphibian… X X X Tiktaalik - fishwith wrist bones!
Transitions from pre-mammal to mammal… Early Mammals Early Pre-Mammals
Transitions from pre-whales to whales… with hippos astheir closestliving cousins!
And what is this biological connectedness called? Right….EVOLUTION!
Did this experience give you a better sense of geological time? Did this experience reveal patterns of fossilsthat you didn’t realize before?
I hope you enjoyed these… Patterns in Time
Geological Time - Over Time (since 1937) The next 2 slides show how the increased precision of radiometric dating over the years has stabalized the timing for the major geological periods - with little change since 1990…
Geological Time - Over Time (since 1937) PALEOZOIC MESOZOIC 1990