Paleozoic Invasion of Land (midterm 2) Flashcards
(26 cards)
Plants initially evolved in _______, then moved into ________, then ________
seawater
freshwater
onto land
With plants’ transition from water to land, what were some of the problems they had to solve?
- had to avoid desiccation (drying out)
- had to develop support (deal with gravity)
- had to develop a reproduction method for land
What are the 2 types of major plant divisions? (+ examples)
Vascular:
- majority of modern land plants
- tissue system of specialized cells for transporting water and nutrients within them
- vascular tissue also provides support
- examples: flowers, trees, ferns
Nonvascular:
- no specialized cells for water and nutrient transport
- live in moist areas
- examples: liverworts, hornworts, mosses
What was the time period with the most major events in land plant evolution?
Devonian > rapid evolution for plants
What were the likely first land plants?
Hepatica
- nonvascular
- have gemma cups > rainfall splashes in them and splashes the gemma out which causes the reproduction
What are 3 adaptations of Vascular plants to help them survive on land?
Cutin:
- prevents desiccation, entry of parasites, oxidation, UV damage
Roots:
- allows greater access to water and nutrients and provides support
Leaves:
- provide light gathering system for photosynthesis
Vascular plants likely evolved from _________
green algae
(evolved before the Silurian)
What was the earliest seedless vascular land plant? reproductive structure?
Cooksonia:
- during the Silurian
- have spores in their cups (reproductive structures)
Explain how vascular plants evolved during the early Devonian
- evolved leaves, roots and secondary growth through Silurian and into the Devonian
*not simultaneous evolutions
Explain the steps of the life cycle of a fern which is a *seedless vascular plant
What is the most important thing to note about this cycle?
- ferns releases spores into the environment
- Spores germinate in *moist soil
- eventually grows into a gametophyte plant (bears both gametes - eggs and sperm)
- young growing fern is still attached to gametophyte plant
- continuing to grow and eggs and sperm combining
- eventually a mature fern sporophyte
**it is a water dependent life cycle - needs a moist environment
What is the significance of Heterospory and what is a Progymnosperm
Heterospory = production of two different size of spores by a single plant
Progymnosperm = an intermediate plant - between plants with all same spore sizes and plants that have seeds - *has two size of spores
Explain the important notes about a Gymnosperm plant’s life cycle (vascular plant with seeds)
- Pollen gets released to hopefully enter cones and fertilize the embryonic egg → forming a seed
- Pollen can be distributed by wind (much more effective) - *doesn’t need water
What are the barriers that animals faced while transitioning to land
- desiccation
- gravity
- reproduction
- respiration
What were the first animals to transition to land? what followed them?
*Arthropods came onto land after plants in the Silurian
> Eurypterids and millipedes (first creatures on land)
Amphibians followed plants and arthropods
What is the oldest fossil of a land animal?
a Millipede-like creature (resembles modern millipedes)
What were the first vertebrates to live on land? First kind of evidence of this?
Amphibians
Earliest tetrapod (four footed) tracks as evidence
Explain the link between the lobe finned fish and amphibian
Traditional thought is that the evolutionary progress was from lobe finned fish to the amphibian
Because they have similar morphologies > similar limbs, tooth structure, and overall structure
What is the significance of the Tiktaalik roseae? (amphibian)
- intermediate creature between lobe-finned fish and tetrapods
- first critter that would’ve walked on land
- still very reliant on water and not efficient at maneuvering on land
What are some characteristics of late Devonian amphibians that suggest both suitability to life on land and life on water
Land suitability:
- backbone
- ribcage
- pelvic and pectoral girdles
Water suitability:
- streamlined body
- long tails
- fins on back
What is the significance of the Ichthyostega amphibian
- believed to be fully reliant on land
- had features that suggested they were most suited for land but still features suggesting water suitability as well
- still kind of an in between stage
Explain the Carboniferous coal swamp environment that led to reptile invasion on land
- ferns
- giant dragonflies
- Lycopsids: tree like things but not actual trees - up to 30m tall - branches and leaves like palms
When did reptiles evolve? How do they differ from amphibians?
evolved in late Mississippian (*also late Carboniferous)
differ from amphibians:
- skull structure
- jawbones
- ear location
- limb and vertebral construction
How were reptiles able to diversify and begin displacing amphibians in the Permian?
Because of several advancements:
- method of reproduction
- jaws and teeth
- tough skin and scales
- faster movement on land (and more efficient movement)
What is each part that makes up an Amniote (reptile) egg? What did this egg evolution allow for?
Amnion - Embryo surrounded by liquid-filled sac
Yolk - food sac
Allantois - waste sac
Shell - protection from desiccation
*reptile emerges from egg a miniature adult
* did not need to return to water at any stage in life cycle
