Evidence for Change

Question 1

Outline the three main pieces of evidence for evolution.

Answer 1

• Paleontology - identifying/interpreting/dating fossils.
• Embryology - the study of embryonic development in different organisms and their genetic control.
• Comparative Anatomy - the study of the morphology of different species.

Question 2

What is comparative embryology?

Answer 2

The comparison of invertebrate embryos - presenting features present and not present in the adult (e.g. gills, tail); suggesting evidence for common ancestry.

Question 3

What is a homologous structure?

Answer 3

Structures with similar architecture - but different functions; suggesting evidence for common ancestry/divergent evolution.

Question 4

What is an analogous structure?

Answer 4

A feature with the same function, however, has evolved independently (e.g. wings - feathers and skin).

Question 5

What is a vestigial structure?

Answer 5

The evolutionary leftovers - structures with no remaining purpose, reduced in size to conserve energy.

Question 6

Outline what a phylogenetic tree is.

Answer 6

The evolutionary history of organisms in a family tree.

Question 7

Outline sequencing methods in organisms to determine the effects of evolution and common ancestry.

Answer 7

• Comparative DNA sequencing - finding similarities in DNA code (base pairs).
• Amino Acid sequencing - finding similarities in AA structure and formality - similar to the DNA method.

Question 8

What is a fossil?

Answer 8

The remains of a long-dead organism preserved in the Earth’s crust.

Question 9

What is the fossil record?

Answer 9

The orderly array in which fossils appear in the layers (or strata) of sediment rocks.

Question 10

How are fossils formed?

Answer 10

1) An organism is buried by sediments.
2) Silt/mud may accumulate overtime - protecting it from erosion.
3) Deposits deepen, temperature increases - sediments turn to rock.
4) Movement of tectonic plates lifts the sediments closer to the surface.
5) Erosion reveals the fossils.

Question 11

What are the three main types of preserved remains?

Answer 11

• Amber - insect trapped in tree sap - hardens into amber.
• Tar - Mammoth trapped in a tar pit - tar soaks into the bones stopping its decay.
• Ice - Tiger dies in the cold region - the body is frozen in ice, preserving everything.

Question 12

How are fossils turned to minerals?

Answer 12

1) Minerals from groundwater fill pores of bones.

2) Minerals forming the bone matrix are dissolved away and replaced by minerals in groundwater.

Question 13

What are the methods for dating fossils?

Answer 13

• Relative Dating - compare the age of one thing with another.
• Comparative Stratigraphy - the study of sedimentary rocks - the sequence of sediments in different areas (similar age).
• Index Fossils - a fossil of a species used to relatively dating another.
• Absolute Dating - the chronological age of an object.

Question 14

What is the method used to date fossils involving radioisotopes?

Answer 14

Radiometric Dating - an absolute dating method for determining the chronological age of a rock by measuring the proportion of radioactive material and decay product (half-life theory).
- Radio Carbon - unstable/break down - emit radiation (measured carbon 14 to nitrogen 14)
C14 half-life of 5730 years.

Question 15

What outlines comparative genomics?

Answer 15

Process of comparing the info encoded in DNA (similarities/differences) - the more similar the more related. Can trace common ancestry.

Question 16

What outlines comparative biochemistry?

Answer 16

Process of contrasting basic chemistry that occurs in cells (analyse.compare AA sequence in proteins) - more similar, more related. Can trace common ancestry.

Question 17

What outlines bioinformatics?

Answer 17

Science of managing/analysing biodata using computer tech. Due to large amounts of complex data - important to bioinformatics in genomics.