40 Questions
What is a characteristic of the volcano rabbit?
It is well-adapted to its own habitat
What is the term used to describe a gap left by an arch in architecture?
Spandrel
Why have human efforts to alter sex ratios been surprisingly ineffective?
Lack of genetic variation
What is the reason humans, unlike most other mammals, can get scurvy?
We don't make our own vitamin C
What is genetic drift?
The effect of random processes on genes
What is a term used to describe a gene that is mutated and ineffective?
Pseudogene
Why was there little selection against the mutation that destroyed the ability to make vitamin C?
Because these animals have lived with fresh food for most of our evolutionary history
What is an example of a spandrel in biology?
The redness of blood
What is antagonistic evolution?
A type of evolution that causes behaviours/other phenotypes that look like maladaptation
What is maladaptation?
Suboptimality
What is a prerequisite for genetic drift to cause maladaptation?
Very small population sizes
What is an example of a historical constraint in the evolution of the eye?
The direction of the retina in mammals
What is the name of the enzyme that catalyses the first stage of photosynthesis?
Rubisco
Why do moths fly towards lightbulbs?
Because they interpret the light as the sun or moon
Why do humans tend to crave salt, fat, and sugar?
Because they were scarce in our evolutionary past
What is an example of a trade-off in the evolution of antelopes?
Their long legs are adapted for running, but break easily
What is pleiotrophy?
When a gene has more than one effect
What is an example of a domesticated animal that was selected for sociability towards humans?
Foxes
What is allometry?
A type of pleiotrophy
What is the name of the longest-lived human on record?
Jeanne Calment
What is a possible reason for the lack of adaptation to a changing environment?
Limited genetic variation
What is an example of a byproduct of another trait?
The redness of blood
What is a constraint on the evolution of a trait?
Lack of genetic variation
What is an effect of genetic drift on a population?
Decreased genetic variation
What is a possible explanation for the loss of the ability to make vitamin C?
Genetic mutation
What is a characteristic of antagonistic evolution?
Co-evolution of two species
What is a possible reason for the lack of adaptation to a changing environment in the volcano rabbit?
Evolution has no foresight
What is an example of a historical constraint?
The inability to make vitamin C
What is a possible explanation for the presence of maladaptation in nature?
Antagonistic evolution
What is a characteristic of maladaptation?
Decreased fitness of a population
What is the primary reason why Rubisco, the most abundant protein in the world, has not improved its efficiency over time?
Because it evolved when carbon dioxide was more abundant and oxygen less, and has not had to adapt to new conditions
What is the main difference between the retinas of mammals and squids?
Squids have their retinas in the correct direction, while mammals have them in the opposite direction
What is the reason why moths are often attracted to lightbulbs?
Because they are trying to navigate using the light as a reference point
What is the term used to describe the phenomenon where a gene has more than one effect?
Pleiotrophy
What is the main reason why humans tend to crave salt, fat, and sugar?
Because we have evolved to seek out these substances when they were scarce in our environment
What is an example of a trade-off in the evolution of antelopes?
The development of long legs for fast running at the cost of increased vulnerability to tripping
What is the term used to describe the phenomenon where a trait is not adaptive in a new environment?
Maladaptation
What is the primary way in which natural selection can act on a population?
By accumulating small, probable strokes of luck
What is an example of a historical constraint in the evolution of a particular trait?
The evolution of the eye in mammals
What is the primary reason why the domesticated fox has characteristics such as a distinctive color pattern and a shortened snout?
Because they are correlated with the selected trait of sociability
Study Notes
Maladaptation in Nature
- Maladaptation can be seen in nature, but it is less common and less noticeable.
- Examples of what is not maladaptation include adaptation to a disappearing habitat, such as the volcano rabbit, and antagonistic evolution.
Spandrels
- A spandrel is an architectural term for a gap left by an arch and is not necessarily an adaptation itself.
- Example: The redness of blood is a byproduct of other selected traits and is not an adaptation in itself.
Genetic Drift
- Genetic drift is the effect of random processes on genes and can cause maladaptation in small populations.
- Humans have a high risk of maladaptation due to genetic drift because of small population sizes throughout history.
- Vitamin C mutation is an example of genetic drift, as it is a mutated and ineffective gene in great apes and some other primates.
Pleiotrophy
- Pleiotrophy occurs when a gene has more than one effect, such as the selection for sociability towards humans in domesticated foxes.
- Characteristics like color patterns and shortened snouts are correlated with the selected characteristic.
Allometry
- Allometry is a kind of pleiotrophy, where a gene has multiple effects, and can cause non-adaptive or maladaptive features.
- Example: A bat's long toes might be an adaptation for hanging upside down or a side effect of having extremely long fingers.
Historical Constraints
- Historical constraints are evolutionary limitations imposed by past adaptations.
- Example: The eye's structure in mammals, where the light passes through the membrane, nerve fibers, and ganglion cells before reaching the rods and cones, is a historical constraint.
- Squids' eyes have a more efficient structure, with their retinas in the right way round.
Rubisco
- Rubisco (ribulose 1, 5-bisphosphate carboxylase/oxygenase) is the most abundant protein in the world and catalyzes the first stage in photosynthesis.
- However, it is hundreds or thousands of times slower than other enzymes due to historical constraints and has not improved since its evolution.
Time Lags and Novel Environments
- Maladaptation can occur when there is a time lag between environmental change and adaptation, such as with moths navigating electric light.
Trade-Offs
- Trade-offs can result in maladaptation, such as with antelopes' long legs, which are adaptive for fast running but have disadvantages like tripping and breaking easily.
- Ageing may be a trade-off against another trait.
Maladaptation in Nature
- Maladaptation can be seen in nature, but it is less common and less noticeable.
- Examples of what is not maladaptation include adaptation to a disappearing habitat, such as the volcano rabbit, and antagonistic evolution.
Spandrels
- A spandrel is an architectural term for a gap left by an arch and is not necessarily an adaptation itself.
- Example: The redness of blood is a byproduct of other selected traits and is not an adaptation in itself.
Genetic Drift
- Genetic drift is the effect of random processes on genes and can cause maladaptation in small populations.
- Humans have a high risk of maladaptation due to genetic drift because of small population sizes throughout history.
- Vitamin C mutation is an example of genetic drift, as it is a mutated and ineffective gene in great apes and some other primates.
Pleiotrophy
- Pleiotrophy occurs when a gene has more than one effect, such as the selection for sociability towards humans in domesticated foxes.
- Characteristics like color patterns and shortened snouts are correlated with the selected characteristic.
Allometry
- Allometry is a kind of pleiotrophy, where a gene has multiple effects, and can cause non-adaptive or maladaptive features.
- Example: A bat's long toes might be an adaptation for hanging upside down or a side effect of having extremely long fingers.
Historical Constraints
- Historical constraints are evolutionary limitations imposed by past adaptations.
- Example: The eye's structure in mammals, where the light passes through the membrane, nerve fibers, and ganglion cells before reaching the rods and cones, is a historical constraint.
- Squids' eyes have a more efficient structure, with their retinas in the right way round.
Rubisco
- Rubisco (ribulose 1, 5-bisphosphate carboxylase/oxygenase) is the most abundant protein in the world and catalyzes the first stage in photosynthesis.
- However, it is hundreds or thousands of times slower than other enzymes due to historical constraints and has not improved since its evolution.
Time Lags and Novel Environments
- Maladaptation can occur when there is a time lag between environmental change and adaptation, such as with moths navigating electric light.
Trade-Offs
- Trade-offs can result in maladaptation, such as with antelopes' long legs, which are adaptive for fast running but have disadvantages like tripping and breaking easily.
- Ageing may be a trade-off against another trait.
Understanding maladaptation and its differences from adaptation in nature, including examples of disappearing habitats and antagonistic evolution.
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