Paleozoic Invertebrate Evolution Flashcards
What was so significant about the Ediacaran Environment
hard part first found in Ediacaran Fauna
- it was the first evidence of simple ecological interactions
What was the Cambrian Explosion
apparent burst in diversity
what is significant about the Cambrian Explosion
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
What were the potential causes of the Cambrian Explosion
- 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
What are the 4 stages of oxygen being in the atmosphere during the Cambrian Explosion
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
What is the Emergence of Shelly Fauna
it is the earliest known organisms with hard parts
Define Endoskeleton
internal skeleton
Define Exoskeleton
external shells
what are characteristics of a good exoskeleton
- provides UV protection
- prevents drying out in marine environments
- allows body size to increase
- provides attachment points for muscles
-offers protection against predators
Define Pelagic
Organism that live in the water column
what are the different organisms in the Pelagic
-Plankton
-Phytoplankton
-Zooplankton
-Nekton
Define Plankton
Floaters go where current takes them
Define Phytoplankton
planktonic plants (microscopic)
Define Zooplankton
planktonic animals (microscopic)
Define Nektons
active swimmers
What are the 2 different types of Nektons
- vertebrates (fish)
- invertebrates (squids)
Define benthic
organisms that live on seafloor
Define Epifauna
animals
Define Epiflora
plants
Define infauna
animals that live in the seafloor
Define Sessile
live in one place ( stuck in a place permanently)
Define mobile (motile)
move around on seafloor
What are the 4 animal feeding strategies
1.suspension feeders (Filter Feeders)
2. Herbivores
3. carnivores
4. Sediment-deposit feeders
Define Suspension feeders (Filter Feeders)
remove microscope plants, animals and dissolved nutrients from seawater
Define Herbivores
Feed on plants
Define Carnivores
Feed on animals
Define Sediment-deposit feeders
Extract nutrients from sediments
Define Trophic levels
tiers of food production and consumption
What are the different Trophic Levels
- Primary producers (autotrophs)
- Primary consumers
- Secondary consumer
- Tertiary consumers
- Transformers and decomposers
Define Primary producers (autotrophs)
Produce their own food (plants)
Define Primary consumers
Mostly suspension-feeders
Define Secondary consumers
Feed on primary consumers
Define Tertiary consumers
Feeds on Primary and Secondary consumers
Define Transformers and Decomposers
Breakdown dead organisms that have not been eaten
Define the Cambrian Marine Community
- Dominated by trilobites, inarticulate brachiopods and Archaerocyathids
Define Archaeocyathids
- major reef builders
- sponges
- benthic, sessile, suspension feeders
- went extinct at the end of the Cambrian
Define Brachiopods
- Benthic, sessile, suspension feeders
- still alive
What are the 2 different types of Brachiopods
Inarticulate: Chitin phosphate shells
Articulate: Calcium carbonate shells
