Biology: Evolution and Species

Evolution

• Develops the diversity of life on earth
• Explains how different species emerged

Species

• A community of animals that can produce offspring with one another
• Members may resemble each other in appearance but have different traits and characteristics
• Each species has unique DNA

Cells and DNA

• Every creature is made up of cells
• Cells have a nucleus containing chromosomes, which hold DNA
• DNA consists of different genes that carry life information
• Genes determine characteristics and traits of a living creature

Creation of DNA

• Excess production of offspring leads to more differences
• Heredity: passing of DNA to offspring
• Recombination: random mixing of DNA from two creatures
• Mutation: random change in DNA, which can be negative (illnesses or cancer) or positive/neutral (e.g., blue eye color)

Keywords

• Random: all evolutionary processes are based on chance
• Selection: each individual undergoes natural selection due to factors like predators, parasites, toxins, habitat changes, and climate

Anatomical Directional Terms

• Used to minimize confusion when discussing body areas
• Anatomical Position: face forward, arms at sides, palms forward, and feet forward

Directional Terms

• Superior: toward the head or upper part of the body
• Inferior: toward the feet or lower part of the body
• Posterior: further back or dorsal
• Anterior: further front or ventral
• Medial: toward the midline of the body
• Lateral: toward the side of the body
• Proximal: closer to the axial body or trunk
• Distal: further from the axial body or trunk
• Superficial: closer to the surface of the body
• Deep: further from the surface of the body