Core Biology Concepts: Organization, Emergence, Structure-Function, Genetics, Metabolism, Systems, Evolution

Organization and Emergence

Life is highly organized; organization is visible in structure, pattern, and uniformity across biological systems.
Emergence: new properties arise at a higher level of organization due to interactions among components at lower levels.
Example: photosynthesis in a leaf cell results from complex interactions among molecules within the chloroplast, including photosynthetic pigments and internal membranes.
If those molecules and structures are removed from their organized context and placed in a test tube, the emergent property of photosynthesis does not manifest.
Key principle: emergence arises from interactions at lower levels; the whole can exhibit properties that its parts do not possess in isolation.
The whole is greater than the sum of its parts: a cell has properties that exceed the simple sum of its organelles and molecules.
Reductionist approach: to understand a complex system (e.g., a plant cell), scientists study its components (organelle, molecules) to explain how the system works.
Organization → emergence across higher levels; this theme will recur as we study cell structure and function.
This theme helps explain how complex biological phenomena arise from simpler components and interactions.

Structure and function are related at all levels of biological organization; form influences function and is shaped by natural selection.
Example: the lung’s branching structure (bronchi, bronchioles, smaller airways) increases surface area, aiding gas exchange with the circulatory system.
Although alveoli are where gas exchange occurs, the highly branched architecture maximizes surface area and efficiency.
Not limited to the lungs: muscle cells rely on the arrangement of protein filaments that slide relative to each other to produce contraction and movement.
The overarching theme: structure (form) is adapted to support function through evolutionary processes.

Genetic information is transmitted from one generation to the next and guides cellular and organismal processes.
Sexual reproduction transmits genetic information from parents to offspring via the fusion of egg and sperm, leading to a fertilized egg and subsequent embryo development.
DNA contains genes; gene expression translates genetic information into functional products.
Example: lens cells are densely packed with crystalline proteins responsible for the lens structure; the crystalline gene contains information for producing crystalline protein; when expressed, crystalline protein is produced in the lens.
Each cell contains the entire genome, but specific genes are turned on in particular cell types, yielding cell-specific traits and functions.
Biologically, many behaviors and life strategies can be viewed as strategies to reproduce and pass genes to the next generation.
The meaning of life from a biology perspective is often framed as reproductive success and gene propagation, even though other disciplines may offer different meanings.

Living things are transformers of energy and matter; metabolism encompasses the processing and transformation of both.
Example ecosystem dynamics: plants capture light energy and convert it into chemical energy via photosynthesis; consumers obtain chemical energy by feeding on producers; energy eventually dissipates as heat.
Energy flow through systems involves transformations (light → chemical energy) and transfers (chemical energy from one organism to another) with some energy lost as heat.
Matter transformation: organisms transform matter, not just energy, by building and remodeling their own molecules (e.g., proteins) from building blocks like amino acids derived from consumed matter.
Overall, metabolism governs how energy and matter are acquired, transformed, and utilized to maintain organization and life processes.

Living things interact with other living things and with the nonliving environment; interactions occur within and among systems.
A system is defined by the coordinated actions of its component parts (e.g., a cell is a system composed of organelles and molecules).
Systems within an organism (e.g., organ systems) interact with other organisms (e.g., a plant interacting with an elephant) in complex ways.
To study a system, one often uses a reductionist approach: analyze its component parts and their interactions to understand the behavior of the whole.
This theme emphasizes cross-scale interactions, from molecules to organisms to ecosystems.

Evolution is biology’s unifying theme; it explains both unity and diversity in life.
The idea that “many things in biology only make sense in the light of evolution” frames how traits and behaviors are understood.
Example: beach mouse vs. inland mouse—same species with populations exhibiting different fur colors due to genetic differences shaped by natural selection in different environments.
Over long timescales, populations can diverge sufficiently to become separate species; however, they can often be traced back to a common ancestor.
Phylogeny describes the branching pattern of life’s history, inferred from genetics, morphology, and other data; it helps reconstruct evolutionary relationships.
The theme of evolution underpins our understanding of life’s unity and its vast diversity.

Adopting these core themes as a framework helps organize new information and enhances problem-solving across topics.
The interplay between reductionist and holistic (emergent) perspectives informs how we approach biological questions.
Biologically grounded meanings (e.g., reproduction) contrast with broader philosophical or religious interpretations of life, highlighting different lenses for understanding.
These themes will be revisited and elaborated in future lectures as we dive deeper into cell structure, function, genetics, metabolism, systems biology, and evolutionary biology.