NGSS Biology

Biology: Constructing
Explanations about

Structure and Function in

Living Systems

Introduction to Missouri State Standard LS1.A.1

Introduction to LS1.A.1

●Missouri state standard LS1.A.1 focuses on structure and function in living
systems

●Students will learn to construct explanations about how structure relates to
function

●This lesson explores various biological structures and their roles in organisms

What is Structure in Biology?

●Structure refers to the arrangement of parts in an organism

●Examples include:

●Cellular structures (e.g., mitochondria, nucleus)

●Organ systems (e.g., digestive system, respiratory system)

●Body parts (e.g., leaves, wings, fins)

What is Function in Biology?

●Function refers to the purpose or role of a structure

●Functions contribute to:

●Survival

●Growth

●Reproduction

●Adaptation to the environment

The Relationship Between Structure and Function

●Structure determines function

●Function influences the development of structures

●This relationship is crucial for:

●Understanding how organisms work

●Explaining adaptations and evolution

Example 1: The Human Heart

●Structure:

●Four chambers (two atria, two ventricles)

●Valves

●Muscular walls

●Function:

●Pumps blood throughout the body

●Maintains blood flow in one direction

Example 2: Plant Leaves

●Structure:

●Flat, broad shape

●Stomata (tiny pores)

●Chloroplasts

●Function:

●Maximize surface area for light absorption

●Allow gas exchange

●Conduct photosynthesis

Example 3: Bird Wings

●Structure:

●Aerodynamic shape

●Lightweight bones

●Feathers

●Function:

●Enable flight

●Provide lift and maneuverability

●Assist in temperature regulation

Levels of Organization

●Biological structures exist at various levels:

●Molecular (e.g., DNA, proteins)

●Cellular (e.g., organelles)

●Tissue (e.g., muscle tissue, nervous tissue)

●Organ (e.g., stomach, brain)

●Organ system (e.g., digestive system, nervous system)

●Organism

Constructing Explanations

●Steps to construct explanations about structure and function:

●Identify the structure

●Describe its physical characteristics

●Research or observe its role in the organism

●Connect the physical features to the function

●Consider how changes in structure might affect function

Case Study: The Human Eye

●Structure:

●Cornea, lens, iris, retina

●Rod and cone cells

●Function:

●Focus light

●Control light entry

●Convert light into electrical signals

Explanation: The eye's structures work together to enable vision

Adaptations: Structure-Function Relationships

●Adaptations are structures or behaviors that help organisms survive

●Examples:

●Camouflage in chameleons

●Antifreeze proteins in Arctic fish

●Succulent leaves in desert plants

Evolutionary Perspective

●Structure-function relationships evolve over time

●Natural selection favors beneficial structures

●Understanding these relationships helps explain:

●Biodiversity

●Speciation

●Convergent and divergent evolution

Applications in Medicine and Technology

●Understanding structure-function relationships is crucial for:

●Developing new medicines

●Creating prosthetics

●Designing biomimetic technologies

●Example: Artificial heart valves based on natural valve structure

Multiple Choice

Which of the following best describes the relationship between structure and
function in biology?

• Structure always determines function

• Function always determines structure

• Structure and function are unrelated

• Structure and function influence each other

Multiple Choice

Which level of organization would a neuron be classified under?

• Molecular

• Organ

• Tissue

• Cellular

Multiple Choice

How does the structure of a cactus relate to its function in a desert environment?

• Thick stems store water

• Bright flowers attract pollinators

• Deep roots absorb nutrients

• All of the above

Multiple Choice

Which of the following is NOT a step in constructing explanations about structure and function?

• Identify the structure

• Describe its physical characteristics

•  Determine its evolutionary history

• Connect physical features to function

Conclusion

●Structure-function relationships are fundamental in biology

●Understanding these relationships helps explain:

●How organisms work

●How they adapt to their environments

●How they evolve over time

●This knowledge is crucial for advancements in science, medicine, and
technology

●Continue to observe and question the natural world around you!