Lesson 1 Flashcards
Ultimate causation
Understanding the underlying evolutionary reasons behind illness
Malthus (1798)
Populations increase @a more rapid rate than the food supply needed to support them
Jean Baptist Lamarck (1784 - 1829)
Coined term biology, believed in inneraquiredcharacteristies
Darwin (1831)
All species struggle for existence
Phylogeny ( or a phylogenetic tree )
Branching diagram to illustrate relationship between species based on heritable information, the distance between branches equals the genetic or anatomical distance between species
Discovering genes
What’s an in creek announce the discovery of the structure of DNA
Franklin discovered double helix DNA
DNA
Deoxyribonucleic acid
Contains genes
Strand of dna is chromosome
Proteins
Composed of amino acids
RNA
Ex. Collagen
Myosin
Allele
An individual unit of inheritance from each parent or a variant of a gene
Homozygous = two copies of the same allele, either dominant or recessive
Hetero = a copy of each different allele
What is evolution
Change in the gene pool in populationover time
Five mechanisms that can change gene frequencies
1.population can reduce in size: through bottleneck and founder effect
2.reproduction:choosing a mate based on observation differences or geographic location
3.mutations:source of new genetic variation that occurs due to either ;mistakes during dna replication or environmental Tal factors
4.movement: new individuals move into or out of a population (gene flow)
5.natural selection: the differential survival or reproduction of individuals due to variability
Mutations may be
Deleterious; have negative effect
Neutral: have no effec
Advantageous: have positive effect
Darwins natural selection
Variation: All organisms vary, and some of this variation is heritable.
Heredity: Traits are passed from parent to offspring.
Differential Fitness: Some individuals survive and reproduce more successfully due to their traits,
gradually shifting population traits.
●Importance of Variation: Natural selection can only act on existing variation. Without it, populations can’t
adapt.
Five mechanisms of evolution
Genetic Drift: Random events (like population bottlenecks or founder effects) can drastically change gene
frequencies, especially in small populations.
Non-Random Mating: Mate choice based on traits (e.g., location, appearance) can increase the frequency
of some alleles over others.
Mutation: Random changes in DNA, which are the only source of new genetic variation. Can be harmful,
neutral, or beneficial.
Gene Flow: Movement of genes between populations through migration. Increases genetic diversity.
Natural Selection: The most well-known mechanism. It favors traits that increase survival or reproduction
in a given environment.
Human vs. Pathogen evolution
Humans evolve slowly: Long life spans, slow reproductive cycles.
Pathogens evolve rapidly: Especially viruses like SARS-CoV-2. They replicate quickly and mutate often,
enabling them to evade immune systems.
Mismatch Problems: Our slow evolution can’t keep up with rapid environmental and cultural changes
(e.g., processed food, sedentary lifestyles), leading to chronic disease.
Cultural evolution
Unlike genetic evolution, culture can change almost instantly (e.g., adoption of smartphones).
Humans inherit both genes and culture — a dual inheritance system.
Culture can accelerate adaptation (e.g., creating vaccines) or introduce risks (e.g., junk food,
misinformation)
Cultural bias in evolution
Content Bias: Preferences for certain types of information (e.g., high-fat food).
Indirect Bias:Choosing cultural traits based on associated signals (e.g., copying celebrities).
Frequency-Dependent Bias:
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Conformity bias:Adopting the most common behavior.
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Rarity bias: Preferring uncommon or novel traits (e.g., fashion trends).
Why can culture be maladaptive
Agriculture increased food availability but also introduced disease, poor diet, and crowding.
Urbanization and technological changes can lead to low physical activity, stress, and fertility issues.
Variation can be:
Adaptive, neutral, maladaptive
