Reach for the Sky Flashcards
List the main issues with Bryophytes.
-poor ability to capture water and retain it
-limited to damp places
-poor water transport
-limited nutrients (ombrotrophic)
-limited height
What major innovations where seen in the Rhynie chert flora?
vascular tissues (Rhynia gwynne), microphylls and mycorrhizal associations with fungi
What are the characteristics of Lycopodiophytes?
-reproduce via spores
-alteration of generations
-dominant sporophyte
-vascular system (xylem)
-simple leaves (microphylls)
-secondary growth
What is primary and secondary growth?
Primary growth=cell division at the tip resulting in the elongation of tissues
Secondary growth=cell division at the cambia resulting in lateral growth
Explain how members of the Lycopodiophyta were able to grow into trees, due to evolving the ability to do secondary growth and how this led to the formation of the first forests.
Lycophytes developed vascular tissues, which were essential for supporting taller plants.
Secondary growth enabled the production of additional xylem layers, thickening the stems and roots. This strengthened the plant and improved water and nutrient transport, crucial for supporting larger sizes.
What are microphylls?
Small leaf-like structures with a single unbranched vascular strand they were a precursor to more complex leaves and are seen in plants associated with the Rhynie chert.
What are Mycorrhizal Associations?
Mutually beneficial relationships with fungi that allows for nutrient capture over large areas (Aglaophyton)
What caused the formation of coal during the carboniferous?
Carboniferous swamp forests, dominated by giant lycopods like Lepidodendron and Sigillaria, were highly productive ecosystems. The high rate of plant growth and the anoxic conditions in waterlogged swamps led to the burial of massive amounts of organic material, forming coal.
Describe the changing atmosphere and environment of the carboniferous.
-oxygen levels spiked up to 35%=larger lifeforms could evolve
-CO2 levels dropped=carbon sequestration in the from of coal and lead to the development of megaphylls
-The drop in CO2 and change in climate lead to carboniferous rainforest collapse
What are megaphylls?
“Large Leaf”-defined by their branched veins structure not size. This innovation allows for a larger surface area resulting in better light and heat capture and water uptake due to the presence of more stomata.
What are Pteridophyta?
A group of vascular plants that reproduce via spores rather than seeds. They lie between non-vascular plants like mosses and vascular seed plants like gymnosperms and angiosperms. Modern
examples are ferns and related groups such as horsetails.
Identify key features of the ferns and horesetails that distinguish them from bryophytes and lycopods.
-xylem and phloem for water and nutrient transport, allowing larger sizes
-sporophyte is dominant and independent, with large fronds or stems
-true roots and leaves present (megaphylls in ferns, reduced leaves in horsetails)
-occupy diverse habitats
The Horsetails
Genus:Equisetum
-have a ring of xylem
-extensive roots
-deciduous
-Strobili (cone like structures which produce spores)
Progymnosperms
An extinct group of plants that represent a transitional stage between early vascular plants and seed plants (gymnosperms). They were prominent during the Devonian and early Carboniferous periods and played a crucial role in the evolution of modern seed plants exhibiting early tree like growth.
Example: Archaeopteris
Pteridospermatophyta
“Seed ferns” that developed during the late Devonian.
-They were not true ferns but rather early seed plants with fern-like leaves.
-They reproduced via seeds, not spores borne on or near the fern-like leaves.
-They had ovules and pollen, indicating advanced reproductive strategies compared to spore-producing plants.
