biodiversity and evolution

• Dinosaurs no longer exist today
• Extinction of dinosaurs or other organisms might be caused by environmental factors or human activities
• Some animals before are very different from the animals we have now
• Some animals may look the same but have distinct differences from each other
• Some animals may not be related to one another but they have similar functional features and characteristics
• Biodiversity


  The variety of life on earth, including species diversity, genetic diversity within each species, and ecosystem diversity
• Evolution


  The change in the characteristics of a species over several generations, relying on the process of natural selection
• Natural selection


  The process through which populations of living organisms adapt and change, where individuals in a species show variation in physical characteristics due to differences in their genes
• The evidence for evolution is compelling and extensive
• Macroevolution


  Large-scale changes that occur over extended time periods, such as the formation of new species and groups
• Microevolution


  Small-scale changes that affect just one or few genes and happen in populations over shorter time scales
• Microevolution and macroevolution are the same process of evolution, occurring on different time scales
• Theory of evolution by natural selection

  The theory proposed by Charles Darwin and Alfred Russell Wallace in the 19th century, where the fittest organisms are most likely to survive and reproduce, passing on their traits to the next generation
• Evidence for the theory of evolution

  • Homologous structures
  • Analogous features
  • Similarities in biological molecules
  • Embryonic development
  • Biogeographical patterns
  • Fossil record
  • Direct observation of microevolution
• Homologous structures


  Unique physical features shared by two or more species, suggesting a common ancestor
• Vestigial structures


  Structures that are often reduced in size and have lost their major ancestral function
• Analogous features


  Similar structures that have evolved independently in organisms without shared ancestry, due to similar selective pressures or environments
• Convergent evolution


  The process where similar physical features evolve independently in different organisms due to similar environments or selective pressures
• All living organisms share the same genetic material (DNA), genetic codes, gene expression processes, and molecular building blocks, suggesting a common ancestor
• Closely related species exhibit similar embryonic development, even when their adult forms are quite different
• Biogeographical patterns provide clues about how species are related to each other, based on the distribution of organisms on Earth
• The fossil record, though incomplete, provides information about what species existed at particular times in Earth's history
• Some populations, like microbes and insects, can be observed evolving over relatively short time periods. this is a type of?


  microevolution
• Evolution through natural selection can result in biodiversity