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Exploring Plant Evolution and Physiology - Coggle Diagram
Exploring Plant Evolution and Physiology
Life on Land
Evidence for Embryophyte Emergence
Key Adaptations:
cuticle
vascular system
stomata
Challenges
Stebbins 1974
Vegetative
Water and nutrient acquisition
Desiccation stress
aid in desiccating sporophyte
structural support
reproductive and dispersal
Relatively more CO2
CO2 about 8-15x higher
Terrestrialization
~470MYA
Major evolutionary changes
Fossil evidence
earliest evidence from spores and tissue fragments
cryptospores
liverwort macrofossils
~390MYA
Major Innovations
Alternation of generations
sporophyte generations
sporophyte evolves dominance
Summary
Development of seeds and pollen
Evolution of vascular tissue
water conducting cells
food conducting cells
LIfe Cycle Evolution
Sporophyte Evolution
Antithetic theory
Gametophyte Dominant
Both Independent
Gametophyte Reduced
Stomata
Functional Considerations
Gas Exchange (CO2 in, O2 out)
Transpiration
water use effiiency
Photosynthesis support
provides ATP for potassium pump
guard cell control
active metabolic processes
Evolution
one of earliest land plant features
What is it?
Indeterminate Growth
Continuous growth throughout lifespan
Meristematic tissue responsible for growth
apical meristem
totipotent
ancestral, found in charophytes
mitosis
PMAT, cytokinesis
Allows for adaptation to changing environmental conditions
Vascularization
Evolutionary Origins
Transition from non-vascular to vascular plants
Development of specialized conducting tissues
Xylem
conducts water and minerals from roots to shoots
composed of tracheids and vessel elements
Phloem
transports sugars and organic nutrients throughout the plant
composed of sieve tubes and companion cells
Vascular Primary Tissue Arrangement in Shoots
Arrangement of vascular bundles in stems
supports structural integrity and transport efficiency
Wood
secondary xylem produced by vascular cambium
provides structural support and water conduction in woody plants
