BIOLOGY 4TH QTR

• Genetic Engineering


  Allows scientists to modify genomes of a variety of organisms, from bacteria to plants and animals, to either improve the characteristics of the organism or make biotechnology products
• Genetically Modified Organism (GMO)


  An organism whose genome has been modified in some way, usually by using recombinant DNA technology
• Transgenic Organism


  An example of a GMO that has had a gene from another species inserted into its genome
• Biotechnology


  The use of natural biological systems to create a product or achieve some other end desired by humans
• Evolution is the biological process that describes how populations of organisms change over time, leading to the diversity of life on Earth
• Descent with Modification


  A fundamental concept in evolutionary biology that encapsulates the idea that species evolve and change over successive generations, passing on heritable traits from ancestors to descendants
• Gene Frequency / Allele Frequency


  The proportion of a particular allele (variant form of a gene) within a population's gene pool. Changes in gene frequency over successive generations play a crucial role in the process of evolution
• Genetic Variation


  The diversity of alleles, genes, and genetic traits within a population or species. It serves as the raw material upon which evolutionary processes act
• Sources of Genetic Variation

  1. Mutations

  2. Genetic Drift

  3. Founder Effect

  4. Bottleneck Effect

  5. Gene Flow

  6. Natural Selection and Adaptation

  7. Intersexual Selection

  8. Intrasexual Selection
• Natural Selection


  The process where organisms with favorable traits for their environment tend to survive and reproduce, passing on these advantageous traits to their offspring
• Peppered Moths (Biston betularia)


  • Before industrialization, light-colored (peppered) moths were prevalent and well-camouflaged on lichen-covered trees, while dark-colored moths were rare. As industrialization spread, dark-colored moths became more prevalent due to their increased camouflage on the darker trees
• Mutation


  Random changes in an organism's DNA sequence, occurring naturally due to errors in replication, environmental factors, or other causes. Mutations introduce genetic variation within populations, providing raw material for evolution
• Evolution of Antibiotic Resistance in Bacteria


  • Mutations in bacteria can lead to the development of resistance to antibiotics. Over time, these resistant bacteria multiply and spread, leading to the development of a population that is less susceptible or even immune to the antibiotic
• Genetic Drift


  Random changes in the frequency of alleles (different forms of a gene) within a population due to chance events, particularly influential in smaller populations
• Founder Effect


  • When a small group of individuals establishes a new population, the genetic composition of the new population may differ from the original population due to chance
• This example illustrates how a mutation in bacteria, providing resistance to antibiotics, has contributed to an evolutionary change within bacterial populations, highlighting the adaptive nature of organisms and the importance of understanding and managing evolutionary processes in the context of healthcare and medicine.
• BIO02


  General Biology 2
• Genetic Drift


  Genetic drift is a mechanism of evolution that refers to the random changes in allele frequencies within a population over generations. It's driven by chance events and can have a significant impact, particularly in smaller populations. This phenomenon occurs due to stochastic (random) variations in the transmission of alleles from one generation to the next, rather than selection based on fitness.
• Examples of Genetic Drift


  • Founder Effect
  • Bottleneck Effect
• Founder Effect


  When a small group of individuals establishes a new population, the genetic composition may differ from the original population due to the limited genetic diversity of the founding individuals.
• Bottleneck Effect


  Occurs when a population undergoes a drastic reduction in size due to environmental events or human activities, resulting in decreased genetic diversity.
• The Visayan warty pig (Sus cebifrons) is a critically endangered species native to the Visayan islands in the Philippines.
• Historically, the Visayan warty pig population faced severe habitat loss and hunting pressures, resulting in a drastic reduction in their numbers.
• The Visayan warty pig population has undergone a significant reduction in size due to habitat destruction and hunting, potentially leading to the bottleneck effect.
• Process of Genetic Drift - Bottleneck Effect


  1. Population Reduction

  2. Loss of Genetic Diversity

  3. Genetic Drift and Allele Loss

  4. Limited Variation in Survivors

  5. Evolutionary Consequences
• Due to the bottleneck effect, the Visayan warty pig population might have reduced genetic diversity, making it more vulnerable to diseases, environmental changes, or reduced adaptive potential compared to the original, more genetically diverse population.
• Conservation efforts, such as captive breeding programs and genetic management, aim to mitigate the effects of the bottleneck by increasing genetic diversity and preventing further loss of alleles within the population.
• Gene Flow


  Gene flow occurs when individuals or their gametes (reproductive cells) move between populations, introducing new alleles into a population or reducing genetic differences between populations.
• Gene flow can counteract the effects of genetic drift, increase genetic diversity, and potentially bring new adaptations into a population.
• The Galápagos Islands are famous for their diverse array of finch species that helped inspire Charles Darwin's theory of evolution.
• Different species of finches inhabit various islands in the Galápagos archipelago, each adapted to their specific ecological niches.
• Gene flow between populations of finches on different islands can contribute to evolutionary changes and the diversity of finch species.
• Process of Gene Flow and Evolution


  1. Island Isolation

  2. Migration and Gene Flow

  3. Interbreeding and Allele Exchange

  4. Influence on Evolution

  5. Adaptive Traits
• Gene flow between populations of Galápagos finches allows for the exchange of genetic material, influencing the genetic diversity and potentially contributing to the evolution of these bird species on different islands.
• It can introduce new variations that might confer advantages in adapting to local ecological conditions, leading to changes in the populations' characteristics over time.
• Baron Georges Cuvier


  A prominent French naturalist and paleontologist who made significant contributions to the fields of comparative anatomy, paleontology, and the early understanding of extinction. While Cuvier did not support evolution as proposed by later scientists like Charles Darwin, his work laid important foundations for the study of fossils and the concept of extinction, which indirectly influenced evolutionary thought.
• Fossil Studies and Catastrophism


  • Fossil Examination: Cuvier meticulously studied fossils and made detailed comparisons between extinct and living organisms. His work in comparative anatomy allowed him to identify similarities and differences between ancient and modern species.
  • Catastrophism: He proposed the theory of catastrophism, suggesting that the Earth's history was marked by a series of sudden, catastrophic events (such as floods or geological upheavals) that led to the extinction of certain species. Cuvier believed these catastrophes allowed new species to appear abruptly in the fossil record.
• Jean-Baptiste Lamarck


  A French naturalist and biologist, made significant contributions to evolutionary theory, especially in the early development of ideas about the mechanism of evolution. His work laid the groundwork for later evolutionary thinking, although some of his specific ideas were later refuted.
• Inheritance of Acquired Traits


  Lamarck proposed that organisms could pass on traits acquired during their lifetimes to their offspring. He suggested that changes in the environment would cause an organism to adapt by using or not using certain body parts. These acquired traits would then be inherited by future generations.
• Taxonomy


  The branch of systematic biology that identifies, names, and organizes biodiversity into related categories