Ch. 13 Flashcards
Know the four main types of support for evolution we discussed in class. (Study mostly from notes)
Fossil, Biogeographical, Anatomical, and Molecular evidence
Fossil- what is it? How do they form?
Any evidence of an organism from more than 10,000 years ago.
Compression, intact preservation, impression, cast, petrifaction
What is Biogeography?
Description of the geographical distribution of life
What are the longest chunks of time in earth’s history, vs the shortest?
(Eon, Era, Period, Epoch)
Approximately how long ago, rounded to the nearest 100 million years, was the Cambrian explosion, and what was it?
543 million years ago
Many life forms show up- ancestors of all life forms today
How can you tell how old a fossil is?
What is the difference between the two ways?
By using relative dating or absolute dating.
Relative dating uses the position in rock layers to tell if one thing is older than another.
Absolute dating can tell you exactly how old something is based on radioactive decay.
What is a half life?
The time it takes for half the atoms in a sample to decay. It’s used to tell when it still had 100% of its nitrogen and carbon.
Why aren’t all organisms that ever lived fossilized?
Things decay and get eaten, bones decay quickly, and soft bodied things would not fossilize because they would just be squished
What is the theory of plate tectonics?
The plates move through Continental drift.
Convection currents form ridges and trenches
What are the names of the different supercontinents that have been around in the past?
Pangea- when everything was one continent
Laurasia
Gondwana
What are hot spots?
Form island chains as tectonic plates shift. Reveals the ongoing movement of the tectonic plates.
Ex: Hawaii
Why might you see closely related species in places that are far apart?
Continental drift
Why are there placental mammals all over the world, but mostly marsupials in Australia?
Australia is more isolated, so the placental mammals could not get there
Why did the placental mammals show up in the fossil record later in South America than in other continents?
South America was isolated until more recently
What is Wallace’s line and why are there different species on different side of the line?
This is due to climate change. There were glaciers in the past that allowed the animals to move from one island to the other.
