Introduction to Human Biology

The course represents a shift in focus from abstract biological concepts to human-specific topics. It covers fundamental aspects of biological sciences, including the definitions of science, a study of the human species, biological anthropology, and human evolution.

Basic Concepts and Principles

• Genetics and DNA Inheritance: Understanding genetics is crucial for studying human biology. For example, the inheritance of traits such as eye color or genetic disorders like cystic fibrosis can be traced using Punnett squares.

• Evolutionary Processes: Exploring how allele frequencies change over time can explain phenomena such as antibiotic resistance in bacteria. For instance, when antibiotics are overused, bacteria with resistance genes survive and multiply, changing the allele frequency in the population.

• Human Morphology and Adaptations: The shape and function of the human body parts give insight into evolution and adaptation. For example, the opposable thumb is an adaptation that has aided tool use and manipulation.

Course Structure and Overview

• Upcoming Units:

  • Human Osteology: This unit involves studying human bones and their functions in the body.

  • Forensic Anthropology: This includes methods to identify age, sex, and trauma from skeletal remains, which can be valuable in crime scene investigations.

  • Human Variation: This topic explores how people adapt to different environments, such as lactose intolerance in populations with a history of dairy farming, and variations in skin pigmentation based on UV light exposure.

• Discussions regarding race will be addressed from a biological anthropology perspective, emphasizing that race has no clear biological basis and is more of a social construct.

• The course will also stress the importance of engaging with class materials, readings, and assignments to enhance understanding.

Human Osteology

• Skeletal System: The human skeletal system is unique in its adaptations for bipedalism. Lab sessions will include exercises for identifying human bone casts.

• Skeletons: Comparative analysis of adult and child skeletons reveals that adults typically have 206 bones, while children have around 270, as some bones fuse during growth.

Purpose of the Skeleton

• Structure and Support: The skeleton provides a framework that supports soft tissues and maintains body shape. For example, the vertebral column supports the torso and allows for upright posture.

• Movement: Joints enable a range of motions, such as how the shoulder allows for a greater degree of freedom compared to the more restricted movement of the hip joint.

• Mineral and Nutrient Storage: Bones serve as reservoirs for minerals such as calcium and phosphorus, which are released into the bloodstream as needed.

• Bone Health: Osteoblasts are responsible for the formation of new bone, while osteoclasts break down old bone to maintain strength and density.

• Wolff's Law: This principle states that the bone adapts to the loads under which it is placed. For instance, athletes often develop denser bones in their weight-bearing limbs.

• Osteoporosis: A condition characterized by decreased bone density leading to fragility, often associated with aging, which makes bones more susceptible to fractures.

Anatomical Position and Directionality

Understanding the body's positional terminology is essential for anatomical studies:

• Medial: Closer to the midline of the body.

• Lateral: Further from the midline.

• Proximal: Closer to the trunk of the body (e.g., the elbow is proximal to the wrist).

• Distal: Further from the trunk (e.g., the fingers are distal to the elbow).

• Superior: Toward the head (e.g., the head is superior to the neck).

• Inferior: Toward the feet (e.g., the stomach is inferior to the heart).

Types of Bones

• Axial Skeleton: Comprised of the skull, vertebrae, and ribs.

• Appendicular Skeleton: Includes the limbs and girdles (shoulder and pelvic).

• Significant Bones: Discussion may include bones like the hyoid bone (involved in speech) and the mandible (jawbone), as well as the vertebral column's components like the cervical, thoracic, and lumbar vertebrae.

Evolutionary Perspective on Human Anatomy

• Bipedalism Evolution: The shift to walking on two legs involved changes in pelvic structure, limb proportions, and overall body alignment. For instance, the pelvis evolved to support internal organs and provide balance and support during upright walking.

• Comparative Anatomy: Distinctions between human anatomy and non-human primates, such as differences in brain size and dexterity, provide insights into evolutionary adaptations.

Adaptations for Bipedalism

• Running Capability: Unique adaptations allow humans to run long distances, aided by features like long legs and the ability to sweat, which helps with thermoregulation during prolonged physical activities.

• Scientific Reference: Dan Lieberman's work highlights how evolutionary processes have favored humans for endurance running as a survival strategy when hunting or escaping predators.

Conclusion and Class Participation

Active engagement and participation in discussions are vital for a comprehensive understanding of human biology. Students are encouraged to ask questions, participate in discussions, and explore the material in further detail during labs and assigned readings to deepen their understanding of the topics.