Evolutionary trends[ edit ] Differences between plant and animal physiology and reproduction cause minor differences in how they evolve. One major difference is the totipotent nature of plant cells, allowing them to reproduce asexually much more easily than most animals. They are also capable of polyploidy — where more than two chromosome sets are inherited from the parents.
Evolution Evolution in plants Plants and Animals: Evolution in plants below mentioned article provides an overview on the Evolution in Plants and Animals.
It is defined as the process of gradual and orderly change from one condition to another. Such gradual and orderly changes are taking place in all the living, as well as non-living things.
The evolution, therefore, may be of two types: It explains the changes that are taking place in non-living objects. This is inorganic evolution. It is important in the study of geology, astronomy, chemistry and physics. It is concerned with living world.
The modem living world organic world including both plants and animals has evolved gradually and in orderly manner from primeval ancestors through a process which we speak as organic evolution.
Organic evolution refers to the continuous process by which living beings have come to their present forms and functions. According to doctrine of organic evolution, the present living objects on the earth have descended from the early simpler organisms by the process of gradual modifications and changes.
These modifications and changes are brought about by interactions among organisms and their environments. Through gradual modifications, new individuals with better adaptive features appear. To this we call natural selection. The process of evolution is continuous and it will never come to an end.
There are many good proofs in nature to suggest that evolution is taking place and it is taking place on different patterns. Evolution may speed in either progressive or retrogressive way. Progressive evolution leads the simple forms towards the complex structural and physiological organizations.
There are, however, many examples among plants and animals in which evolutionary transformations lead them from high complexity towards decreased complexity.
Thus, structurally more complex organic forms produce simplified individuals. Such a type of evolution is called retrogressive evolution. The possible derivation of fungi from algal ancestors as a result of loss of chlorophyll, the development of structurally simplified types of flowers from more elaborate and more complex flowers, change from autotrophic nature to parasitic mode of nutrition in parasitic Cuscuta due to loss of chlorophyll are some of the important examples of retrogressive evolution in the plant kingdom.
In the evolution of different groups of plants and animals, many changes occur frequently which follow a similar trend and culminate into a more or less similar morphological organization, although the plants which are subjected to evolutionary changes may be genetically only very distantly related.
Such an evolution is known as parallel evolution. Parallel evolution may run either in progressive direction or in retrogressive direction. Independent evolution of vessels among angiosperms, in some gymnosperms and some of the pteridophytes is one example of parallel evolution.
Parallel evolution proceeding in different plant groups in almost similar way and in nearly similar conditions sometimes produces forms which resemble morphologically one another so closely that it becomes difficult to distinguish them.
This striking condition is sometimes called convergence and this type of parallel evolution is called convergent evolution. The development of hydromorphic and xeromorphic characters in plants of very distantly related groups of angiosperms may be quoted her as examples of convergent evolution.
At this juncture one may believe that evolution is taking place in a continuous and orderly fashion and it produces a series of modifications in the individuals but one confusion may develop in mind and that is—why stages or steps of evolution have never been seen?
The only satisfactory answer to this is that the processes of organic evolution are very slow and they require thousands and millions of years in completion. Unfortunately, the age of man is so short that one cannot see the happenings of many million years in his life time.
It is only by seeing the similarities and dissimilarities in the structural organizations and behaviour of organisms in plant and animal kingdoms, the possible trends of evolution are interpreted.
In brief, the modem concept of organic evolution can be summarized in the following points: Both these processes of evolution are proceeding simultaneously in nature.Plant evolution is the subset of evolutionary phenomena that concern plants.
Evolutionary phenomena are characteristics of populations that are described by averages, medians, distributions, and other statistical methods. The process of biological and organic change within the plant kingdom by which the characteristics of plants differ from generation to generation.
The main levels (grades) of evolution have long been clear from comparisons among living plants, but the fossil record has been critical in dating. The evolution of seeds, with their hard, resilient coats, was almost certainly a key factor in the success of the group.
A second factor was the evolution of pollen grains to protect and transport the male gametes. As a Paleobotany and the Evolution of Plants, 2nd ed. Cambridge: Cambridge University Press, Customers are welcome to visit the nursery from Monday to Friday, to browse the full range on sale and to collect plants, but it is essential that you book an appointment prior to arrival, by email at [email protected](5).
The evolution of plants has resulted in a wide range of complexity, from the earliest algal mats, through multicellular marine and freshwater green algae, terrestrial bryophytes, lycopods and ferns, to the complex gymnosperms and angiosperms of today.
Oct 01, · Short video explaining a few key facts and concepts on land plant evolution from a phylogenetic perspective. This is the English version of a video originally produced in French for the MOOC.