Lecture 1 Flashcards
(16 cards)
What is Natural Theology and who developed the ‘Scale of Nature’?
Natural Theology: The idea that nature reflects God’s design.
Scale of Nature: Aristotle (384–322 BC) categorized life in a hierarchical structure.
Visual Mnemonic: A ladder with plants at the bottom and humans at the top, with clouds labeled ‘Aristotle’s Scale.’
What contributions did Carolus Linnaeus make to evolutionary theory?
Developed taxonomy to classify organisms into Genus and Species.
Example: Homo sapiens.
Visual Mnemonic: A tree with labeled branches, each representing a species, labeled ‘Linnaeus’ Tree of Life.’
How did James Hutton and Charles Lyell contribute to evolution?
Developed gradualism, supported by the fossil record.
Visual Mnemonic: A stack of rocks representing layers of time with fossils embedded, labeled ‘Gradualism.’
What was Jean-Baptiste Lamarck’s theory of evolution?
Organisms adapt to their environment, and changes are passed to offspring (though the mechanism was incorrect).
Visual Mnemonic: A giraffe stretching its neck to reach a tree, with baby giraffes inheriting longer necks.
What was Darwin’s major contribution to evolutionary theory?
Published Origin of Species, introducing natural selection.
Example: Darwin’s finches adapting to different ecological niches in the Galápagos Islands.
Visual Mnemonic: A ship labeled ‘HMS Beagle’ surrounded by finches with different beak shapes.
What are Darwin’s three principles of natural selection?
Variation: Differences exist within populations.
Heredity: Variations are passed to offspring.
Selection: Certain traits improve survival and reproduction.
Visual Mnemonic: A desert with camels of different sizes; the largest camels survive a sandstorm and pass their genes.
What are the key examples of evidence for natural selection?
Biogeography: Adaptation to environments (e.g., Darwin’s finches).
Fossil Record: Shows gradual changes over time.
Comparative Anatomy: Common structures (e.g., mammalian forelimbs).
Embryology: Similar early developmental stages.
DNA Similarities: Chimps and humans share 98% DNA.
Visual Mnemonic: A DNA helix connecting a chimp to a human hand holding a fossil.
What are the two types of polymorphism in populations?
Genetic Polymorphism: DNA sequence changes.
Phenotypic Polymorphism: Observable differences in appearance.
Visual Mnemonic: A butterfly with various wing patterns labeled ‘Phenotypic,’ and a DNA strand labeled ‘Genetic.’
What mechanisms generate genetic variation?
Gene Mutations: Change in single/multiple genes.
Chromosome Mutations: Change in chromosome number.
Recombination: New gene combinations via sexual reproduction.
Visual Mnemonic: A slot machine with DNA icons spinning.
What are some examples of selective pressures?
Evasion of predators (e.g., Peppered moth).
Competition for food (e.g., Giraffes).
Resistance to disease (e.g., African cattle vs. sleeping sickness).
Sexual selection (e.g., Mating displays).
Resistance to toxins (e.g., Antibiotic resistance).
Artificial selection (e.g., Domestic animals).
Visual Mnemonic: A survival game arena with moths blending, giraffes reaching, and bacteria dodging antibiotics.
What is allopatric speciation?
New species form due to geographical isolation.
Visual Mnemonic: Two islands with different birds flying, separated by an ocean.
What is sympatric speciation?
New species form in the same area due to different niches or behaviors.
Visual Mnemonic: A single forest with two types of finches eating different seeds.
What are the three modes of selection?
Stabilizing Selection: Favors intermediate traits.
Directional Selection: Favors one extreme.
Disruptive Selection: Favors both extremes.
Visual Mnemonic: Stabilizing: A bell curve getting narrower. Directional: A curve shifting to one side. Disruptive: A curve splitting into two peaks.
What is balanced selection?
Multiple selective pressures act simultaneously, e.g., Sickle cell anemia and malaria in Africa.
Visual Mnemonic: A tug-of-war rope between malaria and sickle cell anemia.
What are some mechanisms of isolation?
Geographical: Physical barriers (e.g., mountains).
Habitat: Different resource use.
Behavioral: Different courtship patterns.
Temporal: Different mating seasons.
Mechanical: Physical incompatibilities.
Gametic: Sperm and egg incompatibilities.
Hybrid Sterility: Sterile offspring (e.g., mule).
Visual Mnemonic: Animals blocked by walls (geographical), clocks (temporal), and puzzle pieces (mechanical).
What are the differences between asexual and sexual reproduction?
Asexual: Clonal, rapid reproduction, low variability.
Sexual: Slower reproduction, higher variability.
Visual Mnemonic: A bacteria dividing into clones for asexual vs. a diverse flower garden for sexual.
