Introduction to Biology SCI 102: Moduel 1 Essential Concepts, Genetics, Ecosystems, and the Scientific Method

Chloroplasts contain chlorophyll molecules that power photosynthesis in plants and photosynthetic organisms.
Molecular biology is the study of biology at the molecular and atomic levels.
Key characteristics of living organisms include growth, response to the environment, reproduction, metabolism, maintaining homeostasis (such as a internal body temperature of roughly $98.6$ degrees), cellular structure, and passing traits to offspring.
Viruses are considered nonliving because they are not made of cells, consisting only of nucleic acid and protein, though they utilize host cell machinery to function.
Biological fitness, as formulated by Charles Darwin, refers to reproductive success and the capacity to pass traits to viable offspring rather than physical strength.
Emergent properties occur when individual components within a system interact to yield a new, complex function where the sum is greater than the parts. Examples include:
- Table salt ( $NaCl$ ), formed by the combination of sodium metal and toxic chlorine gas.
- Integrated physiological systems such as the gastrointestinal system and the central nervous system.

Human offspring inherit $22$ chromosomes plus an X or Y chromosome from the father, and $22$ chromosomes plus an X chromosome from the mother, totaling $46$ chromosomes.
DNA directs organismal development and growth from a single-celled zygote through adulthood.
DNA resides within the nucleus of eukaryotic cells and in the cytosol of prokaryotic cells.
Discovered in $1953$ as a double helix, DNA is composed of four nucleotide bases: adenine, thymine, cytosine, and guanine (A, T, C, G).
The central dogma of biology states that DNA transcribes into messenger RNA (mRNA), which directs the assembly of amino acids into proteins.

Ecosystems operate via energy transfer: solar light energy powers plant photosynthesis to synthesize chemical energy ( $ATP$ ).
Decomposers, including mushrooms and bacteria, decompose organic matter and recycle essential nutrients back into the soil containing $H_2O$ .
Gas exchange maintains cellular and ecosystem balance: animals inhale $O_2$ and exhale $CO_2$ and water, whereas plants consume $CO_2$ to generate $O_2$ and sugars.
Evolution explains the variation and common ancestry of life over time through natural selection and environmental interactions (epigenetics).
Taxonomic hierarchy categorizes organisms from broadest to narrowest: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
- The three domains of life are Bacteria, Archaea, and Eukarya.
- Complete classification example (American black bear): Domain Eukarya $\rightarrow$ Kingdom Animalia $\rightarrow$ Phylum Chordata $\rightarrow$ Class Mammalia $\rightarrow$ Order Carnivora $\rightarrow$ Family Ursidae $\rightarrow$ Genus Ursus $ ightarrow$ Species americanus.
- The scientific name for humans is Homo sapiens.

The scientific process relies on observations, testable and falsifiable hypotheses, experimental variables, data collection, and conclusions.
Experimental variables include:
- Independent variable: The factor altered or controlled by the experimenter, plotted on the x-axis.
- Dependent variable: The factor measured in response to changes in the independent variable, plotted on the y-axis.
- Control variable: The baseline condition used for standard comparison.
Peer review requires anonymous expert review of scientific research before publication in journals to reduce bias and verify experimental validity.
Academic institutions like MLU provide peer-reviewed literature access through databases, Coho's, Google Scholar, and online library systems.
Public health and scientific communication, as demonstrated by figures like Doctor Anthony Fauci during public crises, rely on evidence-based terminology (e.g., "the evidence suggests").

Extinct Species Cloning & Dinosaurs:
- Question: Is it possible to bring back extinct species like dinosaurs in real life?
- Response: In Jurassic Park, mosquito blood was sequenced and frog DNA filled genetic gaps, enabling single-sex reproduction; real-world research explores de-extinction theories for species like the woolly mammoth or dire wolves. Displays like Sue the T. Rex at the Field Museum illustrate evolutionary transitions.
Science Fair Model Example:
- Participant experience: A shoe-box desert model made of clay was designed to observe how dry terrain shifts and remolds over time without rainfall in Las Vegas.
Taxonomy Query:
- Question: Why is the panda excluded from the genus Ursus?
- Response: The panda belongs to a different genus within the bear family.
SCI 102 Lab Logistics:
- Question: How are SCI 102 lab sections formatted?
- Response: SCI 102 lab sections (instructed by professors such as Jill Lockhart, Sevilla Sharif, or Clark) are conducted completely online and asynchronously via the course lab shell.