Lecture 2 - The diversity of life

Question 1

What are the characteristics that define life?

Answer 1

• Cellular organisation
• Reproduction
• Metabolism
• Homeostasis
• Heredity
• Response to stimuli
• Growth and development
• Adaptation through evolution

Question 2

What are the three ways that we can measure the scale of life?

Answer 2

Unaided eye, light microscopy and electron microscopy

Question 3

What is 1 mm equal to in µm (micrometres)?

Answer 3

1000 µm

Question 4

What is 1µm (micrometre) equal to in nm (nanometres)?

Answer 4

1000 nm = 1 µm

Question 5

What do we measure most cell organelles in?

Answer 5

µm (micrometres)

Question 6

What do we measure components of cells and organelles in?

Answer 6

nm (nanometres)

Question 7

What was Darwin’s idea for natural selection?

Answer 7

The process through which populations of living organisms adapt and change leading to EVOLUTION

Question 8

What are the requirements for natural selection? (4)

Answer 8

Variation, Inheritance, Selection, Time

Question 9

What are phylogenic trees?

Answer 9

Family trees of organisms

Question 10

What are the three domains of life?

Answer 10

Bacteria, Eukarya and Archea

Question 11

According to the three-domain system, which domain is MOST closely related to the eukaryotes?

Answer 11

Archaea

Question 12

Define the Endosymbiosis theory

Answer 12

The Endosymbiosis theory states that two key organelles in eukaryotes (mitochondria and chloroplasts) are derived from bacteria.

Question 13

What is the main difference between Prokaryotic and Eukaryotic Cells?

Answer 13

Membrane enclosed organelles are present in eukaryotes

Question 14

What domain do animals, land plants and fungi all fall under?

Answer 14

Eukarya

Question 15

In the theory of endosymbiosis, mitochondria and chloroplasts descended from
free-living bacteria engulfed in two separate events by a larger cell. What is the
likely order that this happened?

(A) Chloroplasts were engulfed first; mitochondria were engulfed later.
(B) Mitochondria were engulfed first; chloroplasts were engulfed later.
(C) Both events happened at roughly the same time.
(D) Mitochondria were engulfed and then evolved into chloroplasts

Answer 15

(B) Mitochondria were engulfed first; chloroplasts were engulfed later.

Question 16

The BEST description of natural selection is:

(A) the survival of those most able to exploit resources.
(B) the reproductive success of the members of a population best adapted to the
environment.
(C) the overproduction of offspring in environments with limited natural resources.
(D) a change in the proportion of inheritable variations within a population.

Answer 16

(B) the reproductive success of the members of a population best adapted to the
environment.

Question 17

3. Which one of the following statements about natural selection as a mechanism for evolution is TRUE?

(A) Natural selection requires equal reproductive success within populations.
(B) There must be variation within a population for natural selection to act on.
(C) Natural selection requires the inheritance of acquired characters.
(D) Natural selection requires characters to be non-heritable.

Answer 17

(B) There must be variation within a population for natural selection to act on.

Question 18

Which one of the following applies to light microscopy but NOT electron microscopy?

A. Large magnets are used to concentrate the imaging beam
B. Living cells can be examined
C. Two points that are 20 nm apart can be distinguished
D. The internal structure of a mitochondrion can be seen

Answer 18

B. Living cells can be examined.

Light microscopy is suitable for examining living cells because it uses visible light to illuminate samples, which typically does not harm living organisms. In contrast, electron microscopy uses beams of electrons instead of light, which can be damaging to living cells and therefore is not suitable for examining them in their natural state.

Question 19

A cell measures 0.05 mm in diameter. What is the diameter of the cell in micrometers?

A. 500
B. 50
C. 5
D. 0.5

Answer 19

B. 50

(0.05 x 1000)