What is an evolutionary advantage of Endosporic development?
Evolutionary benefits The development of the gametophyte within the spore wall directly reduces the environmental impacts on the gametophytic gene expression resulting in higher genetic variation and rates of diversification.
What is Endosporic development?
Endosporic development is a process that evolved before seed-bearing plant processes and is still used by different classes of organisms, for example, most ferns.
What is Endosporic gametophyte development?
A gametophyte that develops within a spore. For example, the female gametophyte of Selaginella is contained within the megaspore and at maturity only a portion, bearing the archegonia, is exposed through the spore wall.
What is Endosporic germination?
In endosporic germination, the spore protoplast divides within the spore wall, forming a multicellular structure. The protonema develops inside the stretched spore wall.
What is Exosporic and endosporic?
Answer: ENDOSPORIC : development of gametophyte within the spore as in seed plants EXOSPORIC : gametophte developed outside the spore wall e.g : free living multicellular gametophyte. Explanation: hope this helps plz mark as brainlist.
Is development of male gametophyte endosporic?
Solution. Explanation: Male gametophyte development is endosporic, meaning it takes place within the microspore.
What is endosporic and Exosporic gametophyte?
Answer: ENDOSPORIC : development of gametophyte within the spore as in seed plants EXOSPORIC : gametophte developed outside the spore wall e.g : free living multicellular gametophyte. Explanation: hope this helps plz mark as brainlist. hendikeps2 and 1 more users found this answer helpful.
What do you mean by Monosporic development of embryo sac?
The megaspore mother cell divides by meiotic division to give rise to 4 haploid megaspores. Generally, only one megaspore is functional and develops into the female gametophyte or the embryo sac. This is known as monosporic development.
Which is important in development of seed habit?
Development of heterospory or formation of two types of spores is important for the development of seed habit. The two types of spores are smaller male or microspores and larger female or megaspores. Two types of spores form two different types of gametophytes, male and female.
What is sporophytic and gametophytic?
In plants, alternation of generations exists, where the members have haploid and diploid phases. The plant’s haploid phase is called gametophyte and the diploid phase is called the sporophyte.
What is Sporophytic and gametophytic?
What is Exosporic gametophyte?
They have exosporic gametophytes — that is, the gametophyte is free-living and develops outside of the spore wall. Exosporic gametophytes can either be bisexual, capable of producing both sperm and eggs in the same thallus (monoicous), or specialized into separate male and female organisms (dioicous).
Why is the method of formation of embryo sac called Monosporic?
Q. Assertion :The method of development of embryo sac from a single functional megaspore is termed as monosporic development. Reason: In monosporic(Polygonum) type of embryo sac development, usually, the megaspore which is situated towards micropylar end remains functional.
What is Monosporic type of development?
The formation of the female gametophyte from a single functional megaspore is called as monosporic development. The nucleus of functional megaspore divides mitotically to form two nuclei which move to opposite poles. This forms a two-nucleate embryo sac.
Which one of the following is considered important in seed habitat?
Solution : (b) Heterospory is the production of spores of two defferent sizes and of two different developmental patterns. It is the most important evolutionary development in the vascular plants because it has ultimately lead to seed development, which is seen in , Selaginella, Salvinia, Azolla, etc.
What is the origin of seed habit?
The origin and evolution of seed habitation started to occur in the late Devonian period, about 385 million years ago. It began with the evolution of the first modern tree, Archaeopteris species which produced an advanced system of spores called heterospory.
What is the difference between Sporophytic and Gametophytic generation?
Why sporophyte is dominant over gametophyte?
It produces haploid spores that develop into a gametophyte. The gametophyte then makes gametes that fuse and grow into a sporophyte. In many plants, the sporophyte generation is the dominant generation. This means that the sporophyte is larger and lives longer than the gametophyte generation.
What is Endosporic and Exosporic gametophyte?
What is Endosporic and Exosporic?
In exosporic species, the smaller spores germinate into free-living male gametophytes and the larger spores germinate into free-living female gametophytes. In endosporic species, the gametophytes of both sexes are very highly reduced and contained within the spore wall.
What causes endospores to form?
Endospore formation is usually triggered by a lack of nutrients, and usually occurs in gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall. Under conditions of starvation, especially the lack of carbon and nitrogen sources, a single endospore forms within some of the bacteria.
How do endospores help bacteria to survive?
Endospores make survival possible for bacteria which would otherwise kill them in extreme conditions such as high temperature, pressure, chemical damage, irradiation, etc. Endospores of low gram-positive bacteria, in particular, survive through these conditions. Endospores have a unique cellular structure.
What is the function of the cortex of an endospore?
They also function as a carbon and energy source for the development of a vegetative bacterium during germination. The cortex may osmotically remove water from the interior of the endospore and the dehydration that results is thought to be very important in the endospore’s resistance to heat and radiation.
What is endospory in plants?
Endospory in plants is the retention and development of gametophytes, partially or entirely, within the walls of the generative spore. This is a trait present in many heterosporous plant species.