#Evolutionofseed
#seedevolution
#Evolutionofseedhabit
#seedFormation
#fscbiology
#irtisamsbiology
#kingdomplantae
One of the most significant events in the history of terrestrial plants was the development of seed habit. It was an essential change in the reproductive system of the vascular plants which occurred approximately 390 million years ago. The first complete seeds appeared roughly 365 million years ago throughout the late Devonian era. Technically a seed may be defined as a fertilized ovule.
An ovule is an integumented indehiscent megasporangium. Integuments are specialized protective coverings around megasporangium which differ in number. All seed-producing plants are called spermatophytes. Various actions involved in the evolution of seed habit are as follows.
Evolution of heterospory
Retention and germination of megaspore within the megasporangium
Development of protective layers around megasporangium
Reduction to a single functional megaspore per sporangium
Development of an embryo sac within the sporangium
Modification of distal end of megasporangium for pollen capture
Негізгі бет 9.10 Evolution of Seed Habit | Process of seed evolution | kingdom plantae
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