10.4 Evidence For Evolution Flashcards
What is evolution?
The theory that describes the way in which organisms evolve or change over many years as a result of natural selection
What is creationism?
The belief that God directly created all life on Earth, including human beings
What are the key processes scientists use to study evolution?
Paleontology, comparative anatomy, and comparative biochemistry
How are fossils formed?
Animal and plant remains are preserved in sediment that is built up, and deposited to form rocks
How is evidence for evolution provided by the fossil record?
-Fossils of the simplest organisms are found in the oldest rocks, while fossils of more complex vertebrates are found in more recent rocks (so simple life forms gradually evolved into more complex ones)
-The sequence in which the organisms are found matches their ecological links to eachother
-Scientists can show how closely related organisms have evolved from the same ancestor
Why is the fossil record not complete?
-Soft-bodied organisms decompose completely before they can fossilise
-Conditions needed for fossils to form are often not present
-Fossils have been destroyed by the Earth’s movement
-Not all fossils have been discovered
What is a homologous structure?
A structure that appears superficially different in different organisms, but has the same underlying structures
What does the presence of homologous structures provide evidence for?
Divergent evolution.
What is divergent evolution?
Species diverging overtime into 2 different species, becomign less like the original one.
What is comparative biochemistry?
The study of similarities and differences in the proteins and other molecules that control life processes of different organisms.
What are neutral changes in a molecule?
Changes that do not alter a molecule’s function
How do you see how closely 2 species are related using comparative biochemistry?
Comapre the molecule sequence of a particular molecule
-More closely related species have more similar DNA and proteins than 2 that are distantly related.
