Adaptation
any trait of an organism that increases its chances of surviving and reproducing
Mutation
a random change in an organism's DNA; can have positive, negative, or neutral effects on the organism
Natural Selection
the process by which the individuals best adapted to their environment tend to survive and pass their traits to subsequent generations
Speciation
the process of one species developing into two or more species that can no longer mate
Theory
a well-tested scientific explanation
Are all mutations adaptations?
No adaptations are POSITIVE mutations that get passed onto offspring.
What is a mutation?
Change in DNA (the genotype) of an organism - it can produce new traits
How do sexual organisms have variation in their species?
By randomly combining genes in sexual reproduction or when genes mutate.
How do asexual organisms (like bacteria) have variation?
Only by mutating can variation be introduced.
What is required for natural selection to occur?
There must be variation in a population, the variation must be able to be inherited and the organism with beneficial traits must have more offspring.
Do environmental pressures (like floods or droughts) cause mutations and adaptations to occur?
No they occur randomly but then some organisms can survive better.
If an organism may die otherwise can it move somewhere else or create an adaptation?
No, it is random the better suited organisms survive better, natural selection
Why was it an advantage for the finches in the Galapagos to have different shaped beaks?
They could eat different foods with different beaks giving some an advantage in different environments.
Who is Charles Darwin?
A naturalist who traveled the world studying plants and animals.
How do new species develop?
When populations of a species become isolated over a very long time they may change enough where they can no longer mate.
Why is it good to have advantageous traits?
Organisms are more able to survive and reproduce
T or F The original species of finches were all one species but had different shaped beaks.
True
T or F Finches can change to suit their environment.
False
T or F Finches can move away where they are better adapted if the environment changes.
False
T or F In finch populations, different environments select for different beaks.
True
Variations that give organisms an advantage are good because ...
Organisms can survive better and reproduce
When the color of the environment changes (like with the dark ground and the mice) why do the darker organisms populations go up?
The organisms that can be seen easier get eaten first and the population goes down while the population of the harder to see survive better and organisms goes up.
How does bacteria become resistant?
Some bacteria have a mutation that makes them resistant and they survive, then they multiply and are very difficult to kill.
atom
Smallest particle of an element
body fossil
A rock made from the parts of an organism, such as the bones, teeth, shell
brachiopod
An early marine organism with two hard shells
era
A broad time span based on typical life forms
evolution
The process by which modern organisms have descended from ancient organisms
fossil record
All the fossils on Earth
Fossil
Any remains, impression, or imprint of animal or plant life preserved in Earth's crust
geologic time
The period of time ranging from the formation of Earth about 4.6 billion years ago to today
geologic time scale
A record of the geologic events and life forms in Earth's history.
geologist
A scientist who studies the origin, history, and structure of the earth
isotope
A variation of an element
organism
A living thing
paleontologist
A scientist who studies fossils
particle
A small piece of a substance that is still a substance
Principle of Superposition
States that in undisturbed rock layers, the oldest rocks are on the bottom and the rocks become progressively younger toward the top.
radioactive isotope
An unstable isotope that decays at a predictable rate; used in absolute fossil dating
sediment
Pieces of weathered rock, such as sand, deposited by wind, water, and ice.
sedimentary rock
A rock that forms when layers of sediments are stuck together.
tetrapod
A vertebrate with four limbs.
trace fossil
A fossil of a footprint, trail, burrow, droppings, imprint or other trace of an animal or plant rather than of the animal/plant itself.
trilobite
A marine arthropod, now extinct, that lived during the Paleozoic era.
The fossil record shows us that the Earth was once covered primarily in ...
water.
What type of rock are most fossils found in?
sedimentary rock
What are the two types of fossils we studied?
body fossils and trace fossils
What are two ways to determine the age of fossils?
Absolute dating and relative dating
relative fossil dating
Determining age of fossils by their position in layers of rock (superposition).
absolute fossil dating
Using radioactive isotopes in the rock surrounding the fossil to get a more accurate age of the fossil.
Fossils are relatively rare. Why don't we find more?
Soft parts decay or are eaten or the fossil gets destroyed.
Why is the fossil record incomplete?
-Fossils that formed millions of years ago may have been destroyed by geological activity.
- Many early organisms were soft bodied, and soft tissue tends to decay away completely so that no traces were left behind.
- We haven't found all the fossils yet.
How old is the Earth estimated to be?
4.6 billion years old
All tetrapods, whether ancient or modern, are similar in that...
they have limbs with one bone, then two bones, then many little bones, then digits (fingers/toes)
body fossil
hard parts of an organism, such as bones, shells, teeth
How are adaptations and natural selection different?
Adaptations are trait that can help an organism, Natural selection is the process where the environment selects which organisms are better suited in an ecosystem.