Ch. 13 Flashcards Preview

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Flashcards in Ch. 13 Deck (21)
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1
Q

Know the four main types of support for evolution we discussed in class. (Study mostly from notes)

A

Fossil, Biogeographical, Anatomical, and Molecular evidence

2
Q

Fossil- what is it? How do they form?

A

Any evidence of an organism from more than 10,000 years ago.

Compression, intact preservation, impression, cast, petrifaction

3
Q

What is Biogeography?

A

Description of the geographical distribution of life

4
Q

What are the longest chunks of time in earth’s history, vs the shortest?

A

(Eon, Era, Period, Epoch)

5
Q

Approximately how long ago, rounded to the nearest 100 million years, was the Cambrian explosion, and what was it?

A

543 million years ago

Many life forms show up- ancestors of all life forms today

6
Q

How can you tell how old a fossil is?

What is the difference between the two ways?

A

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.

7
Q

What is a half life?

A

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.

8
Q

Why aren’t all organisms that ever lived fossilized?

A

Things decay and get eaten, bones decay quickly, and soft bodied things would not fossilize because they would just be squished

9
Q

What is the theory of plate tectonics?

A

The plates move through Continental drift.

Convection currents form ridges and trenches

10
Q

What are the names of the different supercontinents that have been around in the past?

A

Pangea- when everything was one continent
Laurasia
Gondwana

11
Q

What are hot spots?

A

Form island chains as tectonic plates shift. Reveals the ongoing movement of the tectonic plates.
Ex: Hawaii

12
Q

Why might you see closely related species in places that are far apart?

A

Continental drift

13
Q

Why are there placental mammals all over the world, but mostly marsupials in Australia?

A

Australia is more isolated, so the placental mammals could not get there

14
Q

Why did the placental mammals show up in the fossil record later in South America than in other continents?

A

South America was isolated until more recently

15
Q

What is Wallace’s line and why are there different species on different side of the line?

A

This is due to climate change. There were glaciers in the past that allowed the animals to move from one island to the other.

16
Q

What are Homologous structures?
What are Analogous structures?
Which of the two tells us something about evolutionary history of different species?

A

Homologous structures have a shared evolutionary origin. They reflect common ancestry.
Analogous structures are used for the same purposes in different animals, but have different structures. This is the result of Convergent Evolution.*********

17
Q

What are vestigial structures, and what can they tell us about a species’ ancestors? Examples?

A

A structure that has lost its function.

Ex: Goose bumps on people and hip bones in snakes and whales

18
Q

What is convergent evolution and what are some examples?

A

Produces superficial similarities, which are analogous structures.
Ex: dolphin and shark, wings is birds and insects

19
Q

What two types of molecular structures do biologists use to asses differences between species?

A

Proteins- amino acid sequences

DNA- base pair sequences

20
Q

Why is mitochondrial DNA more useful than nuclear DNA for molecular dating?

A

It is passed down maternally only, and doesn’t get mixed up with the paternal DNA, so it can be traced back directly. It mutates more rapidly

21
Q

Why do fish and human and mice embryos all look similar?

A

Because we all shared a common ancestor