Life and Geologic Time Sci 4.1 Geologic time scale: history of earth most units based on types of...
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Transcript of Life and Geologic Time Sci 4.1 Geologic time scale: history of earth most units based on types of...
Life and Geologic Time
Sci 4.1
Geologic time scale:• history of earth
• most units based on types of living things
Question 1
Units:
• Eon – longest
• Era
• Period
• Epochs – shortest
Question 2
Organic evolution:
time
• how species change over time
Okapi: Relative of the giraffe
Question 3
Species:• Members reproduce with each other to
produce viable offspring.
• viable: can reproduce
Question 4
Natural Selection• Charles Darwin’s idea
• organisms best suited for their environment are “selected” by nature
• all others become extinct.
Question 5
Changes in environment• can pressure species to evolve
Question 6
Artificial selection:• people, not nature, doing the selecting
• domesticated animals, hybrid plants
Question 7
Trilobites (3 lobes)• lived in oceans >200 mil. years, extinct now
• hard exoskeletons made good fossils
• changed over time
Question 8
• Could’ve been 1st creatures to have eyes.
• Some species lost eyes over time.
What’s not needed can be lost over many generations.
Pangea (Pangaea) • when all continents came together
• ~200 mya
• trilobites became extinct
Question 9