Inheritance and Traits

Genes are segments of DNA that code for specific traits like eye color, hair texture, and blood type. Humans have approximately 20,000 genes spread across 23 pairs of chromosomes.

Natural selection is the process where organisms with traits better suited to their environment survive and reproduce more successfully. Over time, this drives evolution.

Adaptations develop over many generations through natural selection. Structural adaptations (like thick fur), behavioral adaptations (like migration), and physiological adaptations (like venom production) all help survival.

The fossil record provides evidence for evolution by showing how organisms have changed over time. Transitional fossils show features of both ancestral and descendant species.