PHYLOGENEY AND ONTOGENY.pptx

PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY,SRI PARAMAKALYANI COLLEGE,ALWARKURICHI.

1. SEMESTER II - IMMUNOLOGY PYLOGENY AND ONTOGENY SUBMITTED TO, DR.S.VISWANATHAN HEAD DEPARTMENT OF MICROBIOLOGY SUBMITTED BY ARUL THIVYA K I M.SC MICROBILOGY

2. INTRODUCTION A famous but scientifically inaccurate phrase, “ontogeny recapitulates phylogeny,” was coined by German biologist Ernst Haeckel (1834–1919) in the 1860s. Ontogeny,  from the Greek for “origin of being,” is the growth of any multicellular (many-celled) living thing from fertilized egg to adult form. Phylogeny,  from the Greek for “origin of a tribe or kind,” is the evolutionary history of a group, often pictured as a family tree.  Therefore, the saying “ontogeny recapitulates phylogeny ,” also called the  biogenetic law , can be restated as “the growth of an individual replays the evolutionary history of its species.”  

3. The  biogenetic law   asserts, for example, that if all vertebrates (animals with spinal columns) evolved from fish, then early in their development all vertebrate embryos should resemble fish.   If the next stage in the evolution of mammals was amphibian, all mammal embryos should next resemble amphibians. This replay of ancestral forms would continue until the adult form of each animal is reached. The process described by the biogenetic law is referred to as recapitulation. For over a century, biologists have known that the biogenetic law is at best a partial truth. There are many connections between ontogeny and phylogeny, but the biogenetic law is too simple. Ontogeny does not, in general, recapitulate phylogeny.

4. ONTOGENY Ontogeny  (also  ontogenesis ) is the origination and development of an  organism  (both physical and psychological, e.g., moral development, usually from the time of  fertilization  of the   egg  to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from  phylogeny , which refers to the  evolutionary  history of a species. Another way to think of ontogeny is that it is the process of an organism going through all of the developmental stages over its lifetime.

5. Initial stages of human embryogenesis

6. Stages Gametogenesis : Formation and maturation of sperm and egg. Fertilization: Fusion of sperm and egg to produce diploid(2N) zygote Cleavage: Mitotic cell division of early embryo , eventually forming a blastula or blastodisc . Gastrulation : Migration and displacement of single layer of surface cells , still mitotically active , so that three distinct layers are usually formed

7. Migration and displacement of single layer of surface cells , still mitotically active , so that three distinct layers are usually formed Ectoderm = external layer. Gives rise to skin and nervous system Mesoderm = middle layer. Gives rise to muscles , circulatory system , most of the skeleton , excretory and reproductive systems , etc. Endoderm = innermost layer. Gives rise to digestive tract and derivatives ( lungs , liver , etc..)

8. Or ganogenesis continuous masses of cells in the 3 primary germ layers become split into smaller groups of cells – each of which will develop into a specific organ or body part of the animal. Growth and differentiation growth of organ rudiments and acquisition of structure and physiochemical properties allowing them to function as adult structures Neurulation In developing vertebrate offspring , a neural tube is formed through either primary or secondary neurulation . Some species develop their spine and nervous system using both primary and seconddary neurulation , while others use only primary or secondary neurulation . In human fetal development , primary neurulation occurs during weeks 3 and 4 of gestation to develop the brain and spinal cord Then during weeks 5 and 6 of gestation , secondary neurulation forms the lower sacral and coccygeal cord

9. How to development human offspring

10. What Is Phylogeny ?? Phylogeny is the evolutionary history of a species or group. There are about 100 million species living on earth today. The morphological and biochemical evidence suggests that all the organisms are genetically related. The genealogical relationships of the organisms can be represented in the form of an evolutionary tree known as the phylogenetic tree. In this, the  species  or groups are organized in such a way that helps to know how they evolved from the common ancestors. Phylogeny helps us know how the genes, genomes and species evolve. It is useful for fundamental and numerical applications.

11. Pylogenetic Trees The phylogenetic tree is also known as the  cladogram . The species or the groups are found at the tips of the lines known as the tree branches. The evolution of species evolved from a common ancestor is exhibited by how the branches connect. The branch points represent the most recent common ancestor of all the groups descended from that common point. Some cladograms are blocky, while the others are diagonal. However, the orientation of the tree does not change the information. In a phylogenetic tree, if two species have the more common recent ancestor, they are more related than those with a less recent common ancestor.

12. Pylogenetic Tree

13. Application Of Pylogeny Classification The Linnaean classification of species is known with the help of phylogeny. Based on the sequence data, more accurate descriptions of patterns of relatedness are available. Forensics The DNA in case of a crime scene or paternity disputes is assessed by phylogeny. Identification of the origin of Pathogens Phylogenetic approaches can be used to know about a new pathogen outbreak. It helps to know the species the pathogen is related to and the source of its transmission.

14. Conservation Phylogeny helps the conservation biologists to make decisions about which species they should try to prevent from extinction. Computing and Bioinformatics The algorithms developed for phylogenetics are also used in software development in other fields.

15. Different between Ontogeny & Pylogeny

16. Reference https://en.m.wikipedia.org/wiki/ontogeny https://en.m.wikipedia.org/wiki/ontogeny-and-pylogeny https://pediaa.com/difference -between-ontogeny-and-pylogeny/

17. Thank You…….