Biology Chapter: Support and Movement

Support and Movement in Organisms

• Organisms require support and movement to interact with their environment effectively. This allows them to obtain food, reproduce, and escape from predators.

Plant Support Systems

• Plants have various support mechanisms, differing greatly from animal support structures.
• Cellulose cell walls: Provide structural support to plant cells, and allow them to hold up the plant against gravity.
• Turgor pressure: Pressure exerted by water inside plant cells, making the cells swell and providing internal support for soft tissues. This is crucial during growth and response to environmental conditions.
• Stems: Support the leaves, flowers, and fruits; conducting water, nutrients, and photosynthesizing products.
• Woody tissues: Tough and rigid, provide long-term support and protection, particularly in perennial plants.

Animal Support Systems

• Animal support and movement significantly differ from plants. Animals have more complex systems specialized for support and movement.
• Skeletal systems: Provide a framework for the body; protect internal organs; and serve as attachment points for muscles involved in movement. There are significant variations in skeletal designs across different animal groups.
• Exoskeletons: External hard coverings in invertebrates; providing protection and support, but often limiting growth.
• Endoskeletons: Internal support structures in vertebrates; composed of cartilage or bone.

Types of Skeletons

• Cartilage: Flexible connective tissue, commonly seen in the embryonic stages of vertebrates and in some adult forms (e.g., sharks).
• Bone: Hard tissue, richer in minerals (calcium & phosphorus), providing strength and support and acting as a calcium reserve for the body.

Types and Structures of Bones

• Long bones: Provide levers for movement (e.g., humerus, femur).
• Short bones: Provide support and cushioning within joints (e.g., carpals, tarsals).
• Flat bones: Protect internal organs and provide broad surfaces for muscle attachment (e.g., ribs, skull).
• Irregular bones: Vary in shapes and functions; support and protection for various parts of the body (e.g., vertebrae).

Skeletal Joints

• Joints connect bones, allowing for movement.
• Fixed joints: Immovable joints (e.g., bones of the skull).
• Slightly movable joints: Limited movement (e.g., vertebrae).
• Synovial joints: Freely movable, allowing for various types of movement (e.g., hinge, ball-and-socket, pivot joints).

Muscle Tissue

• Muscles are responsible for generating movement in animals; crucial for movement, posture, and digestion.
• Skeletal muscles: Attached to bones, responsible for voluntary movements, composed of striated fibers.
• Smooth muscles: Found in internal organs, responsible for involuntary movements, composed of smooth fibers.
• Cardiac muscles: Found only in the heart, responsible for the heartbeat, composed of striated fibers but with a unique structure for coordinating contractions.

Muscle Contraction

• Muscle contraction involves interactions between actin and myosin filaments, leading to the shortening of the muscle fiber.
• Sliding Filament Theory: Describes the process of muscle contraction; the filaments slide past each other to shorten the muscle.
• ATP (Adenosine Triphosphate): The crucial energy source for muscle contraction; its availability dictates the extent of possible muscular activity.

Coordination and Control

• The nervous system helps coordinate movements and actions, integrating information received from sensory organs.
• Coordination between muscles: Controlled responses from the nervous system to ensure smooth integrated movements.
• Receptors: Detect changes in the environment.
• Relay systems: Transport signals from receptors to effectors (muscles).
• Effectors: React to signals; muscles produce the movement, allowing for a response.

Disorders

• Injuries, defects, and imbalances can affect support and movement, leading to disorders like arthritis (inflammation of joints), muscular dystrophy (muscle weakness and degeneration), and osteoporosis (bone loss).

Explore the mechanisms of support and movement in both plants and animals with this quiz. Understand how plant structures like cellulose cell walls and turgor pressure help them stand tall against gravity. Learn the differences between plant and animal support systems and their significance in survival.