THE GREAT HISTORY OF EVOLUTION OF LIVING ORGANISMS

BIO PROJECT CLASS 11

1. T H E G R EA T HISTO RY O F E V O L U T I O N !!

2. PREFACE In this project I have explained about evolution of prokaryotes to eukaryotes. This slides also contains pictures ,cycles and table & graphs which gives us a clear information.

3. TABLE OF CONTENT Theories & scientists Evolution; Prokaryotes Evolution; Eukaryotes Types of evolution 02 03 01 04

4. WHAT IS EVOLUTION ? In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection Evolution relies on there being genetic variation ?  in a population which affects the physical characteristics of an organism. Some of these characteristics may give the individual an advantage over other individuals which they can then pass on to their offspring

5. IMPORTANCE OF EVOLUTION. The mechanism of evolution is triggered by changes in the gene pool or gene collection. Evolution is important because it explains how life developed on Earth and how different species are connected. The evolutionary linkages aid in the addressing of biological challenges, as well as the diversity of life .

6. CHARLES DARWIN Born in 1809 in Shrewsbury, Shropshire, Darwin was fascinated by the natural world from a young age. Growing up he was an avid reader of nature books and devoted his spare time to exploring the fields and woodlands around his home, collecting plants and insects.

7. The 3 ideas of Darwin's theory VARIATION HEREDITY EXISTENCE

8. CHARLES DARWINS CONTRIBUTION Species keep on evolving or changing with time. As the environment changes, the requirements of an organism also change and they adapt to the new environment. This phenomenon of changing over a period of time as per the natural requirements is called adaptation. As per Darwin’s theory, only the superior changes are naturally selected and the inferior ones are eliminated. Thus, not all adaptations contribute to progressive evolution. For example, people living in tropical countries have more melanin in their bodies to protect them from the sunlight.

9. Almost all organisms share common ancestry with some organisms. According to Darwin, all organisms had one common ancestor at some point in time and kept on diverging ever since. His evolutionary theories support the convergent theory and divergent theory of  evolution  with examples. He also studied that the birds of Galapagos Island (Darwin’s finches) developed different beaks as per the availability of the food. This proved adaptive radiation. Similarly, he also observed the Australian Marsupials which showed a number of marsupials emerging from an ancestor.

10. Variation – The changes accumulated over a period of time in an organism usually give rise to a new species. Inheritance – It is the passing on of the variations over generations which ultimately leads to speciation. A high rate of growth of population – This gives rise to more organisms being reproduced by a species than the environment can support. Differential survival and reproduction – The superior variations lead to the survival of a particular organism and the inferior or negative variations lead to extinction. The superior variations are the ones inherited during reproduction.

11. ABOUT– GREGOR MEDEL Gregor Johann Mendel (July 20, 1822 – January 6, 1884) was an Austrian monk whose studies of the inheritance of traits in pea plants helped to lay the foundation for the later development of the field of genetics. He is often called the "father of genetics." His studies showed that there was particulate inheritance of traits according to basic laws of inheritance. The significance of Mendel's work was not recognized until the turn of the twentieth century. Within Mendel, religion and science were harmonized. Living as a monk, he raised and monitored more than 20,000 pea plants inside the walls of his monastery. He was a teacher of physics and also a beekeeper who tried with little success to study the inheritance of traits in bees. His responsibilities in later life in leading the monastery overtook his earlier priority on scientific studies.

12. WORKS OF MENDEL Though , Mendel didn’t research much about evolution but his work on variation among the genes was incredible and gave the world new idea. Once , he crossed two peas of different varieties he came with a notion of dominance and segregation over them as the traits were inherited where he put up this ratio in simple whole no ratio. Based on this Mendel proposed three law s .

13. PHENOTYPE RATIO – F2 GENERATION

14. ALFRED RUSSEL WALLACE Alfred Russel Wallace (1823-1913) was a man of many talents - an explorer, collector, naturalist, geographer, anthropologist and political commentator. Most famously, he had the revolutionary idea of evolution by natural selection entirely independently of Charles Darwin .

15. WORKS OF ALFRED WALLACE… Alfred Russel Wallace was born in Wales in 1823. He has been described variously as a naturalist, a geographer, and a social critic. He even weighed in on the debate as to whether or not life could exist on Mars. However, what he is best known for is his work o In 1859, Darwin published his book On the Origin of Species, which presented his theory of natural selection to a broader audience. The theory of evolution by natural selection became known as Darwin’s theory. Though Wallace’s contributions to the study of evolution were considerable, they are often forgotten. n the theory of natural selection.

16. CARL LINNAEUS- CLASSIFICATION SYSTEM Carl Linnaeus is most famous for creating a system of naming plants and animals—a system we still use today. This system is known as the binomial system, whereby each species of plant and animal is given a genus name followed by a specific name (species), with both names b eing in Latin .

17. PROKARYOTES… It has been theorized that prokaryotes first evolved after a billion years of formation of earth crust. Initially they existed as non oxygen synthesizing bacteria to form large mound like structures called stromatolites . Which are commonly formed by cynobacteria .

18. EVOLUTION OF MACROMOLECULE FROM ORGANIC COMPOUND

19. It was first suggested in the 1920s that simple organic molecules could form and spontaneously polymerize into macromolecules under the conditions thought to exist in primitive Earth's atmosphere. At the time life arose, the atmosphere of Earth is thought to have contained little or no free oxygen, instead consisting principally of CO 2  and N 2  in addition to smaller amounts of gases such as H 2 , H 2 S, and CO. Such an atmosphere provides reducing conditions in which organic molecules, given a source of energy such as sunlight or electrical discharge, can form spontaneously .

20. EVOLUTION OF ORGANISMS BY RNA!!

21. Of the two major classes of informational macromolecules in present-day cells , only the nucleic acids are capable of directing their own self-replication . Nucleic acids can serve as templates for their own synthesis as a result of specific base pairing between complementary nucleotides . A critical step in understanding molecular evolution was thus reached in the early 1980s, when it was discovered in the laboratories of Sid Altman and Tom that   RNA   is capable of catalyzing a number of chemical reactions, including the polymerization of nucleotides. RNA is thus uniquely able both to serve as a template for and to catalyze its own replication .

22. THE FIRST EVOLVED PROKARYOTES …… Microbial mats or large biofilms may represent the earliest forms of prokaryotic life on Earth; there is fossil evidence of their presence starting about 3.5 billion years ago. It is remarkable that cellular life appeared on Earth only a billion years after the Earth itself formed, suggesting that pre-cellular “life” that could replicate itself had evolved much earlier. A microbial mat is a multi-layered sheet of prokaryotes (Figure 1) that includes mostly bacteria, but also Archaeans . 

23. HOW DID THESE PROKARYOTES SURVIVE AND EVOLVED??? .The first microbial mats likely obtained their energy from chemicals found near hydrothermal vent. A hydrothermal vent is a breakage or fissure in the Earth’s surface that releases geothermally heated water . With the evolution of photosynthesis about three billion years ago, some prokaryotes in microbial mats came to use a more widely available energy source sunlight whereas others were still dependent on chemicals from hydrothermal vents for energy and food.

24. MICROBIAL MATS.

25. PROKARYOTES EUKARYOTES The eukaryotes evolved from prokaryotes , To the great extend many scientist and explorers conclude this transformation by endosymbiosis. In fact this is the theory accepted by the world . The hypothesis that eukaryotes evolved from symbiotic asociation from the eukaryotes .

26. THE ENDOSYMBIOTIC THEORY

27. It is thought that life arose on earth around four billion years ago. The endosymbiotic theory states that some of the organelles in today's eukaryotic cells were once prokaryotic microbes . In this theory, the first eukaryotic cell was probably an amoeba-like cell that got nutrients by phagocytosis and contained a nucleus that formed when a piece of the cytoplasmic membrane pinched off around the chromoso mes .

28. EVIDENCE FOR THE THEORY….. Chloroplasts are the same size as prokaryotic cells, divide by binary fission, and, like bacteria, have proteins at their division plane. The mitochondria are the same size as prokaryotic cells, divide by binary fission, and the mitochondria of some protists have homologs at their division plane. Mitochondria and chloroplasts have their own DNA that is circular, not linear .

29. Mitochondria and chloroplasts have their own ribosomes that have 30S and 50S subunits, not 40S and 60S. Several more primitive eukaryotic microbes, such as Giardia and Trichomonas have a nuclear membrane but no mitochondria.

30. DIFFERENCES EUKARYOTES DNA is linear found in nucleus. Presence of membrane bound organelle. Evolved after -3.8 billion year after earth formed. 1-5 micrometer PROKARYOTES DNA is circular and free floating in cytoplasm. Absence of membrane bound organelle. Evolved from the prokaryotes. 10-100 micrometer

31. TYPES OF EVOLUTION

32. ADAPTIVE EVOLUTION Relates to evolutionary changes that happen due to the changes in the environment, this makes the organism suitable to its habitat. This change increases the chances of survival and reproduction of the organism (this can be referred to as an organism's . For example,  on Galapagos island developed different shaped beaks in order to survive for a long time. Adaptive evolution can also be convergent evolution if two distantly related species live in similar environments facing similar pressures.

33. CONVERGENT EVOLUTION The process in which related or distantly related organisms evolve similar characteristics independently. This type of evolution creates analogous structures which have a similar function, structure, or form between the two species. For example, sharks and dolphins look alike but they are not related. Likewise, birds, flying insects, and bats all have the ability to fly, but they are not related to each other. These similar traits tend to evolve from having similar environmental pressures

34. CO- EVOLUION The influence of two closely associated species is known as  coevolution . When two or more species evolve in company with each other, one species adapts to changes in other species. This type of evolution often happens in species that have  symbiotic relationships . For example, predator-prey coevolution, this is the most common type of co -evolution. In this, the predator must evolve to become a more effective hunter because there is a selective pressure on the prey to steer clear of capture. The prey in turn need to develop better survival strategies. The  Red Queen hypothesis  is an example of predator-prey interations.

35. CONCLUSION I sincerely thank my biology teacher Mrs. Meenakshi and the CBSE board for giving a wonderful opportunity to present my project on this topic . A PROJECT BY - PRAVEEN KKRISHNA .M