Loggerhead sea turtle hatchlings face immediate and significant threats to their survival upon birth. As they instinctively travel from their nest to the ocean, they are vulnerable to predators such as gulls and ghost crabs. This high-risk journey illustrates the intense selective pressures that young animals often encounter, where only a fraction may survive.

Survival Challenges for Loggerhead Sea Turtle Hatchlings

Individuals can produce more offspring than their environment can support, which creates competition and "survival of the fittest". Thus, each generation competes for limited resources. 

University of California, Davis

- Heritable Traits
- More offspring are produced than can survive
- offspring vary in heritable traits

Darwin's Key Observations of Natural Selection

Khan Academy. (n.d.). Darwin, evolution, &amp; natural Selection (article). Khan Academy. https://www.khanacademy.org/science/ap-biology/natural-selection/natural-selection-ap/a/darwin-evolution-natural-selection. 

Darwin, evolution, and natural selection

Many traits are passed from parent to offspring. Some of these traits will help with survival and reproduction, which means the individuals with the favorable traits will have more surviving offspring. Because helpful traits are heritable, these specific trait with be more common in the following generations. 

Heritable Traits

Survival Rate of Offspring

Offspring in a generation will not be identical and different traits can vary. These varying traits are also heritable, making different offspring more fit for their environment than others. This also means that a whole generation cannot be favorable, some individuals will survive while others won't. 

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