Trends of gametophyte in evolution of plants
Explain the trends of gametophyte in evolution of the plants?
Expert
A tendency of gametophyte evolution within the plants has been towards the formation of the gametes which are independent from the water. In the bryophytes and in the pteridophytes the fecundation is totally dependent upon the water. Within the phanerogamic plants such dependency is not there.
Another tendency includes the reduction in size and duration of the gametophyte. In bryophytes, the gametophyte is the lasting stage. In pteridophytes, gymnosperms and angiosperms became the temporary stage and its relative size was successively decreased.
A third evolutionary trend is related to the interdependency between the gametophytes and sporophytes. In bryophytes, the sporophyte is solely dependent upon the gametophyte in order to survive. In the remaining plants, the sporophyte refers to the independent stage and the once autotrophic gametophyte in the bryophytes and pteridophytes became dependent on the sporophyte in phanerogamic plants.
Write the other name given to sex chromosomes? What is the main function of sex chromosomes?
Write down the some prophylactic measures against the HIV infection?
Why the cerebellum is more developed within the mammals which jumps or fly?
Are xylem and phloem made of the living cells?
Define the term microbiology. Briefly define it.
What is endosymbiotic hypothesis concerning the origin of the mitochondria? And also write down the molecular facts which support the hypothesis. To which other cellular organelles can the hypothesis as well be applied?
How can you find out if a molecule is non-polar or polar?
What is the basic difference between cutaneous respiration and respiration by diffusion? Does blood contribute in the cutaneous respiration?
Explain, how does male animal realize that female is receptive for the copulation?
What occurs when supply of the oxygen is insufficient in order to maintain aerobic cellular respiration during the muscle exercise?
18,76,764
1946790 Asked
3,689
Active Tutors
1451652
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!