Wed Nov 11 Bio 1001 Cycle 1 workshop Active Recall

``Natural Selection: Editor vs. Creator

Natural selection acts as an editor by selecting among pre-existing random mutations; it does not intentionally create or direct mutations.

Adaptation vs. Perfection

Natural selection results in 'good enough' adaptations constrained by trade-offs and historical lineage, not absolute perfection.

Acellular Nature of Viruses

Viruses lack cytoplasm, a plasma membrane, and ribosomes, relying entirely on host cell machinery for protein synthesis and metabolism.

Shared Trait of Life & Viruses

Inheritance of genetic material (DNA or RNA genomes passed to offspring) and the capacity to evolve across generations.

Factors Influencing Mutation Rates

Driven by population size, generation time, and replication enzyme proofreading fidelity; independent of environmental need.

Mutation Randomness ('Mutation proposes, selection disposes')

Mutations occur randomly throughout the genome regardless of whether they are helpful, harmful, or neutral to survival.

Vestigial Structures (e.g., Cave Salamander Eyes)

Rudimentary features inherited from ancestors that persist because reduced eyesight conferred no disadvantage in dark environments.

Falsifiability Criterion

A hypothesis must generate specific empirical predictions that could conceivably be proven false by observation or experiment.

Viruses vs. Cellular Life

Viruses are obligate acellular parasites lacking cytoplasm and ribosomes; cells possess cytoplasm, cell membranes, organelles, and independent metabolism.

Natural Selection vs. Evolution

Natural selection is a key process that generates adaptation; evolution is the overall change in population allele frequencies over generations.

Role of Environmental Selective Pressure

The environment does not induce beneficial mutations; it determines which pre-existing genetic variants survive and reproduce preferentially.

Evolutionary Trade-offs

Traits that increase reproductive success may carry survival costs (e.g., bright male bird plumage attracting both mates and predators).

Historical Constraints on Evolution

Natural selection modifies existing ancestral structures rather than designing optimal biological solutions from scratch.

Population Size and Rare Mutations

Larger population sizes (e.g., billions of viral particles) provide significantly more replication events for rare mutations to arise.

Scientific Method vs. Absolute Proof

Scientific hypotheses and theories are subjected to empirical testing for potential falsification, rather than seeking unalterable absolute truth.