Chapter 1 Notes: Biology Concepts & Connections (Campbell Biology, 10th Edition)

Biologists organize life into three domains based on cellular organization and genetics:
- Bacteria
- Archaea
- Eukarya
Bacteria and Archaea contain organisms with simple cells (prokaryotes).
Eukarya includes various protists and the kingdoms Fungi, Plantae, and Animalia.

Life is studied across a broad range of scales, from molecules to the entire living planet.
Structural levels are organized in a hierarchy.
Emergent Properties: new properties that arise from the arrangement and interactions of parts at lower levels; they are not present in the individual parts alone.

Science is an approach to understanding the natural world through evidence-based inquiry.
The scientific method involves:
- Observations
- Hypotheses
- Predictions
- Tests of hypotheses via experiments or additional observations
- Analysis of data
A scientific theory must be supported by a large body of evidence and tested through repeatable controlled experiments.

Observation: An entity or phenomenon is observed and deemed suitable for study.
Hypothesis: A tentative explanation for what was observed; developed through inductive reasoning from facts and observations; must be testable.
Prediction: A testable consequence derived from the hypothesis.
Experiment or Observation: Tests of predictions, using controlled design when possible.
Data Analysis: Statistical analysis and interpretation of results.
Conclusion: Hypothesis is supported or rejected.
Communication and Verification: Findings are reported and subjected to peer review; replication by other scientists is sought to ensure reliability.
Implications: New hypotheses can be generated; new information expands observation.

Experiment: A planned series of procedures to test a hypothesis.
Experimental / Independent Variable: The factor being tested.
Responding / Dependent Variable: The factor affected by the test.
Data: The results of an experiment; should be observable and objective.
Test Group vs Control Group:
- Test group is exposed to the experimental variable.
- Control group is not exposed to the experimental variable.

Observation: The flashlight doesn’t work.
Question: Why doesn’t the flashlight work?
Hypothesis #1: Batteries are dead.
Hypothesis #2: Bulb is burned out.
Predictions:
- Replacing batteries will fix the problem.
- Replacing the bulb will fix the problem.
Test of predictions:
- Replace batteries.
- Replace bulb.
Results:
- Replacing batteries: flashlight still doesn’t work → Hypothesis #1 contradicted.
- Replacing bulb: flashlight works → Hypothesis #2 supported.
Source: 2020 Pearson Education, Inc.

Data source: The selective advantage of crypsis in mice by S. N. Vignieri et al., Evolution 64: 2153–8 (2010).
Hypothesis: Animal fur color matching the environment provides camouflage to evade predation.
Experimental design: Fake mice decoys placed in each habitat; half were mismatched to the environment; half resembled native mouse species.
Outcome measure: Predator attacks on decoys.

Beach habitat (light):
- Attacks on camouflaged models: 2
- Attacks on non-camouflaged models: 5
- % Attacks on non-camouflaged models: 71%
Inland habitat (dark):
- Attacks on camouflaged models: 5
- Attacks on non-camouflaged models: 16
- % Attacks on non-camouflaged models: 76%

Example: Evolutionary relationships of red pandas.
Initial hypothesis: Red pandas are most closely related to raccoons based on physical similarities.
Some scientists placed red pandas with raccoons in the same family.
Other evidence (diet and habitat) suggested a relationship with giant pandas.
DNA sequence comparisons provide another explanation: red pandas are the only living species of their own family.

Life is characterized by both unity and diversity.
Evolution is the scientific explanation for this unity and diversity: the process of change that has transformed life on Earth from its earliest forms to today’s variety of organisms.

Evolution
- Common descent with modification
- Mutations: changes in genes that can affect function, development, or behavior; can be deleterious or beneficial (adaptive); inherited by offspring
Adaptations: variations in a population that improve fitness (ability to survive and reproduce)
Natural Selection: greater fitness leads to greater chance of survival and reproduction; more reproduction leads to more mutation and adaptation

Darwin synthesized the theory of evolution by natural selection.
Observations: heritable variations, overproduction of offspring.
Inferences: natural selection—unequal reproductive success leads to evolution of adaptations in populations.
Conceptual flow: population with varied inherited traits → overproduction → elimination of individuals with certain traits and reproduction of survivors → increasing frequency of advantageous traits.

Living processes rely on transmission and use of information.
DNA provides heredity and programs cellular activities; it serves as the blueprint for proteins.
Information from environment includes stimuli, signals, and pathways that regulate body processes and gene expression.

Relationship between structure and function is evident at multiple levels:
- Molecular Level: protein structure correlates with function; example: beta barrels act as openings in cell membranes.
- Cellular Level: long extensions of nerve cells enable transmission of impulses from the spinal cord to the toes.
- Organismal Level: hands evolved for manipulating objects.

Energy flow in ecosystems is unidirectional:
- Entering as sunlight
- Converted to chemical energy by producers
- Passed on to consumers
- Exits as heat
Matter cycles through ecosystems:
- From atmosphere and soil to producers, consumers, and decomposers
- Back to the environment

Biology spans from microscopic to global scales.
Emergent properties arise from interactions among components of a system.
Systems Biology: scientists model the behavior of biological systems by analyzing interactions among their parts.
Emphasis on how parts interact leads to insights about how complex physiological and ecological processes function.