7-Science-Evolution-Final Study Guide- AQs Flashcards
(44 cards)
When is an organism considered to be endangered?
When they have such a small population that they are in danger of becoming extinct.
When is an organism considered to be extinct?
When there are no surviving members of that species
Explain why scientists think the dinosaurs went exiting. When did this occur?
At least one enormous asteroid crashed into Earth 65 mya. This created a huge cloud of dust and debris that blocked out the sun’s light for a long period of time. This disrupted the food web, caused global cooling, etc.
List two factors that contributed to the extinction of the mammoth.
End of the Ice Age and human hunting
List two factors that have caused the decline of the Asian elephant.
Loss of habitat and human hunting
How do we know about prehistoric organisms that lived thousands or millions of years ago?
study fossils
What types of information can fossils provide about organisms?
What it looked like, how it lived, what and how much it ate, etc.
What types of organisms are often preserved in fossils?
Organisms with hard body parts (bones, shells, exoskeletons); aquatic organisms
List three examples of trace fossils.
Footprints, trails, borrows, egg shells, feces
Describe the ground conditions for the footprints to have become preserved?
soft sediment; a layer of soil must have deposited fast enough to cover and protect the tracks
What evidence do we need to know if larger prints come from larger/heavier organisms?
depth of the foot prints
What is the difference between a observation and an inference? List an example of each from one of the footprint cards.
It is a fact that the larger tracks became more widely spaced (observation), but it is only a theory or interpretation that it meant that the organism started to run (inference)
How do scientists determine how to divide geologic time into periods.
Based on the first or last appearance of certain fossils (index fossils)
List two types of organisms that first appeared on Earth.
bacteria and algae
List the time periods in order from the oldest to the most recent.
Precambrian (4.5 billion-550 million years ago)
Paleozoic (550-245 mya)
Mesozoic (245-65 mya)
Cenozoic (65 mya- present)
Which time period represents the longest amount of time (84%)? Shortest (1%)?
Precambrian (longest)
Cenozoic (shortest)
During which time period did life on Earth really diversify?
Paleozoic
If you don’t find fossils from a particular organism, can you conclude that the organism did not exist during that time? Why or why not?
No! The soil conditions may not have been suitable for fossils to form.
How can you determine if two organisms lived at the same time?
They are found in the same rock layer
How can you use rock layers to determine which fossils are likely to be from an extinct species?
If they disappear form the fossil record and do not reappear
Why do scientists creat stratigraphic columns?
As a record of the rock layers and fossils they observed in different locations
Turtles compete with one another. A faster turtle is more likely to escape from a predator. Over many gyrations, the average speed of turtles increases. Give an explanation for Lamark and for Darwin.
Lamark: As turtles move to escape predators they become faster (they acquire speed). This trait is passed to offspring.
Darwin: Turtles vary in speed. The faster turtles are better able to escape predators than slow turtles; therefore, the fast turtles survive longer to reproduce (and pass on their genes for speed)
Why is Darwin’s theory of evolution more convincing than Lamark’s?
We know (after studying genetics) that acquired traits are not passed to offspring.
List two examples of animal adaptations.
Odor, camouflage, poison, speed, shells, sounds, etc.
