Terrestrilisation Flashcards
What is the period covered by terrestrialisation?
Ordovician to Devonian
What is terrestrialisation?
Colonisation of the land habitat from the sea, via freshwater habitats, by plants and animals
What was the rate of terrestrialisation like?
Staggered/ stepwise changes in multiple lineages these subjected to increased competition over time driving evolutionary change
What are the physiological barriers to life on land?
Methods of respiration
Water management
Osmoregulation
Digestion
Temperature control
Reproduction
Dispersal
Sensory perception -
Support
Locomotion
Why was the method of respiration a barrier to life on land?
Needed to adapt to breathing in atmosphere
Why was water management a barrier to life on land?
Needed for drinking and survival
Why was osmoregulation a barrier to life on land?
needed to maintain water pressure and water retention
Why was digestion a barrier to life on land?
Adapting to eating in the atmosphere
Why was temperature control a barrier to life on land?
water regulates temp while self regulation needed on land
Why was dispersal a barrier to life on land?
Needed movement from birth to living site otherwise clumping occurs
What are the 4 basic methods of water management in the fossil record?
Aquatic
Cryptic
Poikilohydric
Homoiohydric
What are aquatic organisms water management system?
microscopic organisms which live in interstitial water in soils
What are some examples of aquatic organisms that live in interstitial water?
Some microscopic nematodes
Protozoans
some algae
What habitat do cryptic forms live in?
constant high humidity such as soil and tropical forest litter
What are some examples of cryptic form organisms?
Some algae
Homosporous ferns
Earthworms, leeches
What do Poikilohydric organisms require?
high humidity to function but can tolerate desiccation by drying out and rehydrating
when conditions become more favourable
What are some examples of Poikilohydric organisms?
Cyanobacteria
Some bryophytes (mosses, lichens), algae
Some higher plants
Mites
How do Homoiohydric organisms manage water?
osmoregulation, waterproof cuticles,
and internal water transport systems
What are some examples of Homoiohydric organisms?
Most tracheophytes (vascular plants)
Tetrapods (vertebrates, 4 feet)
Insects
Arachnids
Some isopods
Terrestrial molluscs (e.g. gastropods)
How does the cuticle help with water management in homoiohydric organisms?
Waxy external and internal layers to regulate water content
What is the role of stomata in vascular plants?
Stomata within cuticle to regulate water loss, and allow gaseous exchange
What is the role of the xylem?
water transport