evolution of eukaryotes.pptx

brief description on evolution of eukaryotes from prokaryotes

1. EVOLUTION OF EUKARYOTES A report by Asna Aasim M.Sc Zoology IInd Sem

2. Definition of eukaryotes ; A eukaryote is a type of cell or organism characterised by having a membrane-bound nucleus and other membrane bounded organelles , typically larger and more complex than a prokaryote. introduction

3. WHY IS IT IMPORTANT TO STUDY THEIR EVOLUTION? Origin of Life By unraveling the mechanisms that led to the formation of complex cells and multicellular organisms, scientists gain insights into the early stages of life's development on our planet. Fundamental Knowledge It provides insights into the origins of cellular structures, functions, and biological processes that are shared among diverse organisms. Ecology and Ecosystems Understanding eukaryotic evolution contributes to our understanding of ecological interactions and ecosystem dynamics Evolutionary Biology The study of eukaryotic evolution provides valuable insights into the processes of natural selection, adaptation, and speciation.

4. ORIGIN OF EUKARYOTIC CELLS Where did it happen?? The earliest evidence of eukaryotes comes from fossils dated to around 1.6 billion years ago. These early eukaryotes were likely single-celled organisms with some of the features characteristic of eukaryotic cells, such as a nucleus. How about when?? The evolution of eukaryotic cells is believed to have occurred around 1.6 to 2.1 billion years ago, during a period known as the Proterozoic Eon.

5. THE ENDOSYMBIOTIC THEORY: MERGING OF PROKARYOTES The endosymbiotic theory is a scientific explanation for the origin of certain organelles within eukaryotic cells, specifically mitochondria and plastids (like chloroplasts), through a process of symbiosis between ancestral prokaryotic cells and early eukaryotic cells. This theory was proposed by biologist Lynn Margulis in the 1960s and has since become widely accepted as a key concept in understanding the evolution of eukaryotic cells.

6. EVIDENCES MITOCHONDRIA CHLOROPLASTS

7. FIRST EUKARYOTIC ORGANISMS Some of the earliest evidence of eukaryotic life comes from fossils known as Grypania spiralis. These fossils, dated to around 1.85 billion years ago, represent filamentous structures that could be remnants of early multicellular or colonial eukaryotes.

8. What’s the role of endosymbiotic theory in the evolution of endomembrane system seen in eukaryotes?

9. The endosymbiotic theory , as mentioned earlier, plays a significant role in the evolution of the endomembrane system. Endosymbiosis involved the engulfment of bacteria (such as mitochondria and plastids) by ancestral eukaryotic cells.These engulfed bacteria eventually developed into organelles with their own membranes, initiating the formation of the endomembrane system. As eukaryotic cells evolved, their internal membranes likely underwent modifications and expansions. This allowed for increased cellular compartmentalization and specialization of functions..

10. Compartmentalisation and Specialisation

11. The diversification of eukaryotes refers to the evolutionary process by which these organisms evolved into a wide array of forms, functions, and ecological niches. This process led to the development of the diverse and complex eukaryotic life we observe today, including plants, animals, fungi, and various single-celled organisms. DIVERSIFICATION OF EUKARYOTES

12. EVOLUTION OF COMPLEX LIFE EVOLUTION OF COMPLEX LIFE : TRANSITION TO MULTICELLULAR ORGANISMS

13. WHAT LED TO EMERGENCE OF GENETIC DIVERSITY FROM UNICELLULARITY ?? Sexual reproduction likely played a key role in the evolution of eukaryotes by contributing to genetic diversity and enabling the development of more complex organisms. As eukaryotes evolved, sexual reproduction became intertwined with the processes such as meiosis and fertilisation , leading to the formation of multicellular organisms with specialised tissues and cell types. SEXUAL REPRODUCTION

14. Eukaryotes on land The transition of eukaryotic organisms from aquatic to terrestrial environments presented numerous challenges that required the evolution of various adaptations. Moving from water to land required organisms to cope with fundamental changes in factors like desiccation, gravity, gas exchange, and nutrient acquisition . As a result, many eukaryotes developed specialized structures and behaviors to thrive in these new environments.

15. RISE OF PLANTS, ANIMALS & FUNGI The emergence of plants, animals, and fungi from eukaryotic ancestors represents key milestones in the evolutionary history of life on Earth. These three major groups, collectively known as the three domains of multicellular life, have diverse characteristics and play critical roles in ecosystems

16. MODERN EUKARYOTIC DIVERSITY

17. CONCLUSION In summary, the evolution of eukaryotes represents a remarkable journey of complexity, diversity, and innovation over billions of years. From humble beginnings as simple single-celled organisms, eukaryotes have evolved into a vast array of multicellular plants, animals, fungi, and protists, each with unique adaptations and roles in Earth's ecosystems. This evolution has been shaped by a multitude of factors, including genetic changes, endosymbiotic events, environmental pressures, and ecological interactions.

18. BIBL IOGRAPHY https://en.m.wikipedia.org >wiki https://www.oxfordbibliography.com https://www.jstor.org https://chat.openai.com [open AI GPT-3] https://www.googleimages.com [picture courtesy by google]