Paleozoic Invertebrate Evolution

Question 1

What was so significant about the Ediacaran Environment

Answer 1

hard part first found in Ediacaran Fauna
- it was the first evidence of simple ecological interactions

Question 2

What was the Cambrian Explosion

Answer 2

apparent burst in diversity

Question 3

what is significant about the Cambrian Explosion

Answer 3

Most of todays animal phyla first appeared in the fossil record during the Early Cambrian

most animals found from that time period can be attributed to modern groups

Question 4

What were the potential causes of the Cambrian Explosion

Answer 4

• Global warming
  Snowball Earth just ended
• Change in ocean chemistry
  increased volcanic activity raised calcium content
  -Predators
  need to escape predators and catch prey are strong
  -oxygen

Question 5

What are the 4 stages of oxygen being in the atmosphere during the Cambrian Explosion

Answer 5

Stage 1: (3.85 - 2.45 Ga)
- no O2 in atmosphere
Stage 2: (2.45 - 1.85 Ga)
- O2 produced but absorbed into oceans and seabed rock
Stage 3: (1.85 - 0.85 Ga)
- O2 starts to gas out of the ocean but absorbed by land surfaces and formation of ozone layer
Stages 4: (0.85 - present)
-O2 sinks filled , the gas accumulates

Question 6

What is the Emergence of Shelly Fauna

Answer 6

it is the earliest known organisms with hard parts

Question 7

Define Endoskeleton

Answer 7

internal skeleton

Question 8

Define Exoskeleton

Answer 8

external shells

Question 9

what are characteristics of a good exoskeleton

Answer 9

• provides UV protection
• prevents drying out in marine environments
• allows body size to increase
• provides attachment points for muscles
  -offers protection against predators

Question 10

Define Pelagic

Answer 10

Organism that live in the water column

Question 11

what are the different organisms in the Pelagic

Answer 11

-Plankton
-Phytoplankton
-Zooplankton
-Nekton

Question 12

Define Plankton

Answer 12

Floaters go where current takes them

Question 13

Define Phytoplankton

Answer 13

planktonic plants (microscopic)

Question 14

Define Zooplankton

Answer 14

planktonic animals (microscopic)

Question 15

Define Nektons

Answer 15

active swimmers

Question 16

What are the 2 different types of Nektons

Answer 16

1. vertebrates (fish)
2. invertebrates (squids)

Question 17

Define benthic

Answer 17

organisms that live on seafloor

Question 18

Define Epifauna

Answer 18

animals

Question 19

Define Epiflora

Answer 19

plants

Question 20

Define infauna

Answer 20

animals that live in the seafloor

Question 21

Define Sessile

Answer 21

live in one place ( stuck in a place permanently)

Question 22

Define mobile (motile)

Answer 22

move around on seafloor

Question 23

What are the 4 animal feeding strategies

Answer 23

1.suspension feeders (Filter Feeders)
2. Herbivores
3. carnivores
4. Sediment-deposit feeders

Question 24

Define Suspension feeders (Filter Feeders)

Answer 24

remove microscope plants, animals and dissolved nutrients from seawater

Question 25

Define Herbivores

Answer 25

Feed on plants

Question 26

Define Carnivores

Answer 26

Feed on animals

Question 27

Define Sediment-deposit feeders

Answer 27

Extract nutrients from sediments

Question 28

Define Trophic levels

Answer 28

tiers of food production and consumption

Question 29

What are the different Trophic Levels

Answer 29

1. Primary producers (autotrophs)
2. Primary consumers
3. Secondary consumer
4. Tertiary consumers
5. Transformers and decomposers

Question 30

Define Primary producers (autotrophs)

Answer 30

Produce their own food (plants)

Question 31

Define Primary consumers

Answer 31

Mostly suspension-feeders

Question 32

Define Secondary consumers

Answer 32

Feed on primary consumers

Question 33

Define Tertiary consumers

Answer 33

Feeds on Primary and Secondary consumers

Question 34

Define Transformers and Decomposers

Answer 34

Breakdown dead organisms that have not been eaten

Question 35

Define the Cambrian Marine Community

Answer 35

• Dominated by trilobites, inarticulate brachiopods and Archaerocyathids

Question 36

Define Archaeocyathids

Answer 36

• major reef builders
• sponges
• benthic, sessile, suspension feeders
• went extinct at the end of the Cambrian

Question 37

Define Brachiopods

Answer 37

• Benthic, sessile, suspension feeders
• still alive

Question 38

What are the 2 different types of Brachiopods

Answer 38

Inarticulate: Chitin phosphate shells
Articulate: Calcium carbonate shells