Week 23 Flashcards
Define the term adaptation.
An adaptation is a feature that is common in a population because it provides some improved function. Adaptations are well-fitted to their function and are produced by natural selection.
List and define the criteria required for a trait to be considered adaptive.
A trait must be:
Heritable – It must be passed down through generations.
Increase Fitness – It must enhance an organism’s reproductive success.
Functional – It must serve a purpose beneficial to survival or reproduction.
Selected for the purpose – It must have been favored by natural selection for its current function.
Differentiate between true adaptations and categories of traits that are not true adaptations.
Vestigial features: evolutionary leftovers
By-products – traits that are a side effect of something else.
Exaptations- co-opted traits.
Outdated adaptations – intact traits that used to be useful but no more!
Results of genetic drift – may in fact be counteradaptive
Preadaptation - refers to the possibility of a characteristic to
adopt a new biological function with little to no evolutionary modification.
Define, identify, and provide examples for 2 types of mimicry.
Batesian Mimicry: A harmless species mimics a harmful or toxic species (e.g., a nonvenomous snake mimicking a venomous coral snake).
Müllerian Mimicry: Two or more harmful species evolve to look similar, reinforcing the warning signal to predators (e.g., toxic butterflies sharing the same color patterns).
Discuss several examples of adaptations, and identify trade-offs that organisms exhibit in their adaptations.
Example: Rough-Skinned Newt – Produces a potent neurotoxin (TTX) as a defense.
Trade-off: Producing the toxin reduces the number of eggs the newt can lay.
Example: **Garter Snakes **– Some populations evolved resistance to TTX.
Trade-off: Resistance slows crawling speed and affects thermoregulation.
Example: **Herbivore Adaptations **– Monarch caterpillars bioaccumulate toxic compounds from milkweed.
Trade-off: They are limited to a single food source, which could be scarce.
Provide examples of traits that are not adaptive, and categorize them.
Pseudogenes – Nonfunctional remnants of once-functional genes (genetic drift).
Vestigial Structures – Traits that no longer serve a function (e.g., human appendix).
Byproducts of Evolution – Traits that arise as side effects of other adaptations (e.g., the male nipple).
Preadaptation
Class list
Vestigial features: evolutionary leftovers!
By-products – traits that are a side effect of something else.
Exaptations- co-opted traits.
Outdated adaptations – intact traits that used to be useful but no more!
Results of genetic drift – may in fact be counteradaptive.
True or False: Feathers are an adaptation for flight.
Answer: False (Feathers originally evolved for insulation or display and were later co-opted for flight, making them an exaptation.)
True or False: Venoms are an adaptation for the animals that use them.
Answer: True (Venoms are heritable, increase fitness, are functional, and were selected for their defensive/predatory purpose.)
But why don’t mimics evolve to have toxins of their own instead?
Answer: Adaptations have trade-offs. Producing toxins requires energy and resources that could otherwise be used for reproduction or growth. Mimics avoid this cost by only resembling toxic species.
Raccoons’ successful move to city life represents which of the following?
Answer: B. Exaptation (Their dexterous hands and climbing ability, originally evolved for natural environments, were co-opted for urban living.)
The swollen thorns in the acacia-ant relationship represent a(n):
Answer: E. Adaptation (The enlarged thorns evolved specifically to provide shelter for ants, benefiting both species in a mutualistic relationship.)
Cormorant wings are an example of a(n):
Answer: D. Vestigial Trait (They are no longer functional for flight but still exist as evolutionary remnants.)
How do organisms use different energy sources (carbs vs. fats) based on activity level?
Carbs: Used more during high-intensity activities like sports.
Fats: Used more during low-intensity activities like walking or resting.
How do high-altitude environments affect metabolism and oxygen usage?
High-altitude zones have low oxygen, making it harder to burn fat efficiently.
What adaptations do Highland mice have for living at high altitudes?
Their hemoglobin has a higher affinity for oxygen, allowing them to extract more oxygen from the air.
