* Physical characteristics:
* Size: Individuals with larger or smaller body sizes might be better suited to their environment.
* Color: Camouflage or bright colors can influence survival and reproduction.
* Shape: Streamlined bodies in fish or beaks adapted for specific food sources are examples.
* Behavioral traits:
* Mating rituals: Certain behaviors attract mates, increasing reproductive success.
* Foraging techniques: Efficiency in finding and accessing food is crucial for survival.
* Social interactions: Group behavior, such as herding or pack hunting, can provide advantages.
* Physiological traits:
* Disease resistance: Individuals with stronger immune systems are more likely to survive outbreaks.
* Metabolic rate: Efficiency in energy utilization can be advantageous in different environments.
* Tolerance to environmental conditions: Resistance to extreme temperatures, salinity, or toxins.
How Natural Selection Works:
1. Variation: Within a population, individuals have slightly different traits.
2. Inheritance: These variations are often heritable, meaning they can be passed down to offspring.
3. Competition: Individuals compete for resources like food, mates, and shelter.
4. Differential survival and reproduction: Individuals with traits better suited to their environment are more likely to survive, reproduce, and pass on their traits.
5. Accumulation of advantageous traits: Over generations, the frequency of advantageous traits increases in the population, while less advantageous traits become less common.
Key points:
* Natural selection acts on existing variations. It does not create new traits, but it favors those that are beneficial in a specific environment.
* Variations must be heritable to be passed on to the next generation and influence the evolution of the species.
* The accumulation of variations over many generations can lead to significant changes in a species, eventually leading to the formation of new species.
Example:
* The evolution of the peppered moth: The peppered moth exists in two forms, light and dark. Before the Industrial Revolution, the light form was more common, providing camouflage on lichen-covered trees. With industrial pollution, the trees darkened, giving the dark moth an advantage. Over time, the dark moth became more common as it was better camouflaged and less likely to be eaten by birds.
