Lecture 2. Diversity of Life: Conquering the Land

Question 1

When did Earth form ?

Answer 1

4.6 billion years ago

Question 2

What was Earths first atmosphere made up of ?

Answer 2

1. Water vapor
2. Little to no oxygen
3. Nitrogen
4. Carbon dioxide
5. Methane
6. Ammonia
7. Hydrogen

Question 3

How would you describe the early atmosphere ?

Answer 3

Reducing - organic compounds could have formed from simpler molecules

Question 4

What was the earliest form of life ?

Answer 4

Bacteria which used energy from the sun

Question 5

What facilitated the colonisation of land ?

Answer 5

Increase in oxygen

Question 6

What are algae ?

Answer 6

1. Eukaryote
2. Photosynthetic
3. Unicellular and multicellular

Question 7

What are cyanobacteria ?

Answer 7

1. Prokaryote
2. Photosynthetic
3. Unicellular and multicellular

Question 8

What are bacteria ?

Answer 8

1. Prokaryote
2. Non photosynthetic
3. Unicellular

Question 9

When did the first prokaryotes appear ?

Answer 9

3.2 bya

Question 10

When did the first single celled eukaryotes form ?

Answer 10

2.1 bya

Question 11

When did the first multicellular eukaryotes form ?

Answer 11

1.2 bya

Question 12

When was the Cambrian explosion ?

Answer 12

535-525 mya

Question 13

What is the Cambrian explosion ?

Answer 13

A great increase in the diversity of animal forms

Question 14

What happened 500 million years ago ?

Answer 14

Colonisation of land by fungi, plants and animals

Question 15

Where did life evolve ?

Answer 15

In water

Question 16

What are the environmental requirements for plants conquering land ?

Answer 16

1. Formation of sizeable and stable near shore environments
2. Development of soils
3. Amelioration of atmosphere
4. Suitable climatic conditions

Question 17

What are the challenges for organisms abandoning life under water ?

Answer 17

1. Desiccation of the body tissues, requiring some sort of waterproof coating
2. Respiration of gaseous oxygen rather than oxygen dissolved in water
3. Mechanical support (air is not as buoyant as water)
4. Transport water and nutrients about plant
5. Reduce need for water for reproduction

Question 18

What prevents water loss ?

Answer 18

Waxy cuticle

Question 19

What is the function of ANR gene ?

Answer 19

Required to tolerate extreme dessication in mosses

Question 20

Where is the ANR gene not found ?

Answer 20

Flowering/vascular plants

Question 21

What is cellulose the main constituent of ?

Answer 21

Cell walls and fibres

Question 22

What is the function of lignin ?

Answer 22

Binds cells, fibres and vessels (wood)

Question 23

What is the function of hemicellulose

Answer 23

Adds strength to cell walls

Question 24

What is the stele ?

Answer 24

The central cylinder, inside the cortex, composed of the vascular tissue and associated tissues in roots and stems of vascular plants

Question 25

Where were early land colonists found ?

Answer 25

Near shore

Question 26

What protects from desiccation an UV light ?

Answer 26

Spore and seed walls

Question 27

What were the first land plants ?

Answer 27

Green algae

Question 28

What are the closest living relatives of the first land plants ?

Answer 28

Charopytes

Question 29

What was the first vascular land plants ?

Answer 29

Cooksonia

Question 30

What are pteridophytes ?

Answer 30

Vascular plants that reproduce with spores and developed large lobed leaves which are more efficient at capturing sunlight

Question 31

What is the oldest known creature to have lived on land ?

Answer 31

Pneumodesmus newmani

Question 32

What did tetrapods evolve from ?

Answer 32

Lobe finned fishes

Question 33

What is the Tikaalik ?

Answer 33

The first vertebrate capable of crawling on land

Question 34

What is oleanane ?

Answer 34

Produced by many common flowering plants as a defense against insects, fungi and various microbial invaders

Question 35

What are paleosols ?

Answer 35

Ancient soils