Natural selection and biological fitness Flashcards
(21 cards)
What is biological fitness?
The ability of a genotype to survive, find a mate, and reproduce—leaving its genes in the next generation.
At what level does natural selection act?
At the individual and gene level
Genes that increase fitness more likely to passed on
What is selfish herd behavior?
When individuals move toward the center of a group (e.g., sheep) to reduce predation risk
A survival strategy
What is kin selection?
An evolutionary strategy favoring the reproductive success of relatives, even at a cost to the individual
Supports the idea of inclusive fitness
What does Hamilton’s Rule state?
Altruistic behavior is favored when c < b × r, where:
- c = cost to the actor
- b = benefit to recipient
- r = coefficient of relatedness
What is inclusive fitness?
The total genetic contribution to the next generation via both personal reproduction and support of relatives’ reproduction
What is multilevel selection theory?
A view that selection acts on both individuals and the social groups or environments they live in
What is the haplo-diploid system in ants and bees?
Females are diploid (from fertilized eggs); males are haploid (from unfertilized eggs)
Leads to high relatedness among sisters
What is the naturalistic fallacy?
The incorrect assumption that what is natural is inherently good or morally acceptable
Why might male infanticide evolve as a strategy?
It increases male fitness by allowing quicker reproduction with the female
Common in species with male takeovers
What are female counter-strategies to infanticide?
Defense against males or pretending to be fertile to confuse and mate with the new male without conceiving
What are the three “evolution gems”?
- Mechanisms of change (e.g., natural selection, mutation)
- Modification (descent with change)
- Adaptation (traits favored for current function)
What defines an adaptation?
A heritable trait favored by natural selection for its current function
e.g evasion behaviour, efficient proteins, new anatomic access
What does Indohyus tell us about whale evolution?
It shares key features with whales and may be a transitional fossil linking land mammals to aquatic ancestors
What is significant about Tiktaalik?
t is a transitional fossil showing key traits between fish and early tetrapods
e.g limbs, ribs, and a neck
What do feathered dinosaurs suggest?
Feathers may have evolved before flight, likely for insulation or display
What evolutionary change was observed in Anolis sagrei lizards?
Larger predators favored longer-legged males and larger females—traits that enhance speed and survival
What does coevolution in Daphnia and microparasites show?
Parasites rapidly adapt to host genotypes, demonstrating real-time coevolution in lake sediment archives
What did guppy studies show about natural selection?
Rare color morphs had better survival, demonstrating negative frequency-dependent selection
What’s unique about moray eel jaws?
Their pharyngeal jaws resemble a ratchet system, similar to snakes—an example of convergent evolution
How does tetrodotoxin resistance evolve in garter snakes?
Through molecular changes in sodium channels (e.g., tsNaV1.4), coevolving with toxic newts
