Historical Geology - Paliozoic continued (1 & 2)

Question 1

What was going on in terms of distribution of land masses during the Paleozoic?

Answer 1

• Gondwana Large landmass including Africa, South America, Australia, India, Antarctica, and portions of Asia
• Laurentia (proto-North America) - North America, Baltica, Asia
• Panthalassic Ocean- surrounded supercontinents
• Tethys Ocean - Basin between ‘Laurasian land masses’ and Gondwana

Question 2

Describe the Cambrian Palaeogeography.

Answer 2

• large scale inundation of cratons (Stable parts of the lithosphere)
• Topographic highs created through numerous orogenies (forces and events leading to a large structural deformation of the Earth’s lithosphere ie plate collision resulting in mountains)

Question 3

What major change occurred during the odorvician

Answer 3

• Glaciation
  
  • affects sea level and therefore shelf space (Major changes in habitat availability are associated with sea level change)
• Was possible driver for end-Ordovician mass extinction
  Two stepped process
  
  1. Onset of glaciation, killed tropical taxa
     2. Glacial retreat, killed cold-adapted taxa

Question 4

Describe Cambrian Ecosystems

Answer 4

• mostly grazers, suspension feeders (straining suspended matter), and detritivores (obtain nutrients by consuming decomposing plant and animal parts as well as faeces)
• few predators
• Dominated by trilobites, brachiopods, echinoderms,
  and archaeocyathid reefs

Question 5

Describe Odorvician Ecosystems

Answer 5

• Far more complex
• Higher degree of bioturbation
• Greater development of hard parts
• Greater abundance of pelagic and predatory taxa
• Most reef-building archaeocyathids die out at theend of the Cambrian

Question 6

What did the Odorvician era see in terms of diversification?

Answer 6

• huge expansion of diversity
• organisms more specialized
• greater complexity

Question 7

What are the features that define a chordate?

Answer 7

• Notochord - Jawless fish
• Dorsal hollow nerve cord
• Pharyngeal gill slits
• Post-anal tail
• Endostyle

Question 8

How does a chordate differ from a vertebrate?

Answer 8

Vertebrates are distinguished from other chordates by having backbones or spinal columns.

Question 9

What are conodonts? Describe.

Answer 9

A conodont was a vertebrate from the chordates class.

• large eyes
• extremely diverse
• looks like a really small lamprey
• global distribution

Question 10

What happened in the Middle Paleozoic period?

Answer 10

• recovery from mass extinction
• large reef communities
• trilobites remain but lack previous diversity
• first plants on land

Question 11

Describe the terestrial plants of the middle Paleozoic period.

Answer 11

developed adaptations for living on land

• rigid stem
• leaves
• root system
• vascular tissues

Question 12

What was the first land plant?

Answer 12

Cooksonia
– No leaves, no flowers, no seeds, no roots
– Reproduction via spores
– Photosynthesis takes place in the stem

Question 13

How did plants become bigger from the early Devonian to the Late Carboniferous periods?

Answer 13

Root evolution

Question 14

Name a structure that was revolutionary for plants.

Answer 14

Seeds

• free plants from needing water for reproduction
• protect embryo
• feeds embryo

Question 15

How did the climate change from the Devonian to the Carboniferous periods?

Answer 15

Devonian - warm, humid, ice-free
changed to
cooler, drier, glaciation

Question 16

What fish appeared during the mid-devonian period?

Answer 16

chondrichthyan - Shark, rays and chimeras