2- Old And New Species Flashcards
What are the two scientific opinions on how life was formed on earth?
Life was developed due to the conditions or life forms arrived from another planet
What are the ways fossils can be formed?
From the hard parts of animals that do not decay easily
The conditions mean the organism does not decay (from that)
Preserved traces of organisms (eg. Footprints)
Why do most organisms not fossil?
The exact conditions for fossil formation were not present
Early life forms had soft bodies so few traces were left (much of what was left was destroyed by natural disasters)
Why can fossils be useful to scientists?
They can show how much organisms have changed over time
What are some common factors (changes in circumstance) of extinction?
Disease
Predators or competitors
A catastrophic event
Slow evolution
What are the two opinions on why dinosaurs became extinct?
Catastrophic event (most likely an asteroid) Slow process, the ice melting which cools the sea, destroying food (plankton)
How can a new species arise from an existing species?
A group becomes isolated from the rest of its kind in a different environment
When has speciation occurred?
When two populations of what was the same species can no longer successfully breed
How old is the earth and when did life begin?
The earth is 4500million years old and like began 3500million years ago
