Heredity and Adaptation Benchmark

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.