Origin And Phylogeny of Angiosperm

-
Angiosperm:
Vascular Plant Where fruit and flower formation takes place and seen id covered within the fruit is called angiosperm. Such as Oryza sativa, Zea mays.

Origin of Angiosperm:
According to Bentham and hooker angiosperm originated from the evolution of Bennettitales order of gymnosperms flat. Flowering plant Originated from Bennettitales bi-sexual flower. The bi-sexual flowers are small and bear three distinct floral parts. First spirally arranged bracts. Secondly, the whorl of the microsporophyll is female parts, ovule.

The Ranalis order might have been evolved by the gradual transformation of foliaceous bract into perianth, microsporophyll into a male part, and megasporophylls into a female part, spontaneously further developing into gynoecium. 

Comments

Post a Comment

Popular posts from this blog

Diseases caused by Viroid, Transmission, Viroid disease control

-
Image
Diseases caused by Viroid: Viroids are plant pathogens. They infect higher plants and cause diseases like potato spindle tuber disease, and chrysanthemum stunt disease. These infectious RNA particles are responsible for crop failures and subsequently, the loss of millions of money in agriculture annually. Potato, cucumber, tomato, chrysanthemums, avocado, and coconut palms are plants that are commonly subjected to viroid infections. Viroids causes over 20 different plant diseases. The only human disease known to be caused by a viroid is hepatitis D. The list of diseases caused by Viroids are given below:   Transmission: Viroid infections in plants are transmitted by ➢ cross-contamination ➢ mechanical damage to plants as a result of horticultural or agricultural practices. ➢ Some seed or pollen transmitted ➢ aphids ➢ leaf contact (transferred from plant to plant) Viroid infections (hepatitis D) in humans are transmitted by ➢ blood or serum transfusions. Viroid disease control: Viroid i
Read more

Theory of Chemical/Biochemical evolution/Modern theory of the origin of life/Operin-Haldane theory of the origin of life/ Materialistic Theory or Physico-chemical (Part -1)

-
Image
Theory of Chemical/Biochemical evolution/Modern theory of origin of life/Operin-Haldane theory of origin of life/ Materialistic Theory or Physico-chemical Theory: Gradual transformation (transmutation) of inorganic compounds to organic compounds and organic compounds to protocell (life) is called the Biochemical origin of life. Modern biologists agree that the origin of life was a continuous steady process. Life did not come into existence suddenly but was a result of a long series of physicochemical changes. These changes brought about a gradual evolution of the first inorganic and then organic compounds in accordance with the ever-changing environmental conditions. The concept of a biochemical origin of life was first proposed by Russian biochemist A.I. Oparin in 1923 and later supported by English scientist J.B.s Haldane in 1928. Thus, this theory is also called Oparin and Haldane theory. Later, in the year 1936, Oparin published his views in his book, The Origin of Life. The wh
Read more

Theory of Chemical/Biochemical evolution/Modern theory of the origin of life/Operin-Haldane theory of the origin of life/ Materialistic Theory or Physico-chemical (Part -3)

-
Image
F) Formation of colloids, co-acervates (protobionts or pre cells) or origin of primitive cell: The complex organic compounds of primordial soup in ocean aggregated together forming colloidal mass which was surrounded or bounded by water layer was called coacervates. They can grow by absorbing nutrients. Oparin called these aggregates as coacervates while Sidney fox called them Protenoids or Microspheres. The nucleic acid controlled the activities of coacervate and the fats formed a layer around it and showed a great affinity to water. This structure is called Eobiont. Some of the proteins within coacervates acted as enzymes and began metabolic activities. G) Origin of the first cell (Prokaryote): Coacervates may produce the first cell-like structure. The first cell-like structure with the power of division is called Eobiont or Pre-cell. Oparin considered that the coacervates with nucleoprotein gave rise to primitive cells or Eobionts. Oparin also called it as protobiont. The eobion
Read more