Share 7th Grade Science Unit 1 - early life
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Why doesn’t the fossil record show all organisms that have ever existed?
Fossilization is rare, soft-bodied organisms decay, and many
Most organisms never lived long enough to be important
Scientists have already found every fossil on Earth
All organisms are equally likely to become fossils
Fossilization requires certain conditions. Which of the following helps a fossil form?
Being eaten by predators
Floating on the ocean surface
Exposure to air and sunlight
Rapid burial in sediment
What is the significance of the “digits” in the pattern?
They are just for decoration
They make the limb shorter
allow animals to swim, walk, climb, or manipulate objects
They are only found in humans
Why is this bone pattern important?
shows a common ancestor, how limbs adapted for environments
It only applies to birds
shows that vertebrate limbs are all completely different
It proves that fish could not evolve into land animals
Which of the following animals does NOT follow the one → two → many → digits pattern?
Amphibians
Fish
None of the above; all follow the pattern
Humans
What were the first organisms on Earth?
amphibians
land plants
Single-celled prokaryotes
dinosaurs
During which period did the first tetrapods appear?
Ordovician
Silurian
Devonian
Cambrian
Why are land plants important in evolution?
They replaced fish in oceans
They produced shells for protection
They allowed animals to colonize land
They could fly
What was the main type of life during the Ordovician Period?
Marine invertebrates like brachiopods and mollusks
Dinosaurs
Birds
Mammals
Which of the following correctly describes the “one bone → two bones → many bones → digits” pattern?
Only occurs in fish
Shows how vertebrate limbs are related and adapted
Only found in humans
Does not relate to evolution
Which type of organisms is least likely to appear in the fossil record?
Soft-bodied organisms like worms and jellyfish
Fish with bones
Dinosaurs
Animals with shells
What does a cladogram show?
The order in which fossils are found
The size of organisms
The age of rocks
Evolutionary relationships among organism
Organisms that share more traits on a cladogram are:
Always the same species
Less closely related
more closely related
The same age
Which two animals are most closely related according to the cladogram?
Wolf and tortoise
Horse and tortoise
Leopard and house cat
Horse and tortoise
Which animal is least closely related to the others?
wolf
tortoise
kitty cat
horse
During the Cambrian Period, most life forms were aquatic. What does the fossil record from this time reveal?
Humans and mammals becoming the dominant life forms
Water covered the majority of the Earth
Land plants and forests covering Earth’s continents
Large dinosaurs living on land and in the oceans
