Evolution vs. Creationism: Influential Figures

• Evolution revolutionized how we view life, differing greatly from the historical view of ​​"Creationism."
• Evolution posits that all life forms evolved gradually through natural selection, sharing ancestors over vast periods.
• Creationism asserts that a divine being created all life in a short time frame, with distinct species not sharing ancestry

Key Figures in Shaping Darwin's Thinking:

• Malthus: Proposed populations grow exponentially while resources grow linearly, leading to a struggle for existence.

  • This struggle results in only a portion of the population surviving due to limited resources, This idea significantly influenced Darwin's concept of natural selection.

• Lamarck: Proposed inheritance of acquired characteristics, where organisms could pass on traits developed in response to their environment.

  • This concept included the incorrect example of a giraffe's long neck, gave Darwin the inspiration of heritable variations.

• Lyell: Developed the theory of uniformitarianism, stating geological changes occur gradually over extended periods.

  • Lyell's work provided Darwin with a framework for understanding how evolution could happen over long time scales.

• Darwin's observations on the HMS Beagle included shifted plates, fossils, and biological diversity.

• Alfred Wallace independently developed the concept of natural selection alongside Charles Darwin.

  • Wallace's work prompted Darwin to finally publish his own theory on the subject.

Natural Selection Requirements:

• Genetic variation: Traits are passed on by genes, with mutations in DNA causing genetic diversity.
  • Sexual reproduction increases this diversity further.
• Struggle for existence: Competition for resources or environmental pressure. Variation in traits leads to differences in competitive success.
• Differential survival and reproduction: Inherited traits that increase fitness.

Natural Selection Conditions:

• Sexual reproduction between two different sexes creates genetic diversity. This is a necessary condition for natural selection.

Genetic Definitions:

• Trait: A specific, observable characteristic of an organism, determined by its genes, and varies among individuals in a population
• DNA: Molecule inside cells that carries the genetic information responsible for an organism's development and function.
• Chromosome: A thread-like structure in the cell's nucleus, composed of tightly coiled DNA with proteins, which carries genetic information in the form of genes passed from parents to offspring.
• Gene: The basic unit of heredity, a specific sequence of DNA located on a chromosome, containing the information needed to produce a protein, determining a specific trait.
• Allele: One of two or more alternative forms of a gene existing at a specific location (locus) on a chromosome.
• Sexual reproduction is the ultimate source of genetic variation

Mutations:

• A change in an organism's DNA sequence that can occur due to errors during DNA replication, exposure to mutagens or viral infections.
• Mutations can result in altered traits depending on the change.
• Viruses can cause mutations.
• Genetic variation begins with mutations, but sexually reproducing organisms generate extra diversity when forming gametes and during fertilization.

Reproduction:

• Asexual reproduction allows organisms to reproduce completely on their own. It allows for more rapid population growth since the amount of partners are stable.

• Sexual reproduction has the advantage of producing higher genetic diversity and makes it able to make more traits to evolve and adapt.

• Natural selection is the mechanism and the only one that leads to evolution.

• Evolutionary adaptation: A heritable trait or characteristic that develops within a species over time through natural selection, allowing organisms to better survive and reproduce in their specific environment

Adaptations:

• Adaptations are not always perfect due to mutations caused in DNA
• Evolution is the process in which organisms adapt, mute, reproduce, and after time change according to natural selection in order to survive and continue growing

Evidence for Evolution:

• Artificial selection: People choose specific breeds with beneficial traits and breed them together to improve the breed.
• Fossil records: Fossils show how animals changed and evolved over time.
• Homologies: Similarity in DNA and protein sequences suggests relatedness.
• Developmental similarities: Certain organs in animals and humans are similar in form and function.
• Vestigial structures: Useless bones are evidence that species evolved from the same species as others in the past.
• Empirical evidence: Beak depth in birds increases over time as droughts worsen.
• Pesticide and antibiotic resistance: Pests survive chemicals, mate, and have babies that also survive.

Explore the contrasting views of evolution and creationism. Discover how Malthus, Lamarck, and Lyell shaped Darwin's thinking on natural selection, inheritance, and geological change. Understand the core arguments of each perspective.