Chapter 1 – An Introduction to Biology

Flashcards covering key concepts from Chapter 1 notes on principles of biology, evolution, classification, and biology as a discipline.

What is Principle 1 in the unifying principles of life?

Cells are the simplest units of life; all organisms are composed of one or more cells; new cells come from pre-existing cells by cell division.

What is Principle 2?

Living organisms use energy; the maintenance of organization requires energy.

What is Principle 3?

Living organisms interact with their environment—both living and non-living components (e.g., predators and light).

What is Principle 4?

Living organisms maintain homeostasis; the variability for a parameter may differ between species (e.g., body temperature in mammals vs reptiles).

What is Principle 5?

The genetic material (DNA) provides a blueprint that allows organisms to grow, develop, and reproduce.

What is Principle 6?

Populations of organisms evolve from one generation to the next and are related by an evolutionary history; evolution is evidenced by DNA sequences and the fossil record.

What is Principle 7?

Structure determines function.

What is Principle 8?

New properties of life emerge from complex interactions.

What is Principle 9?

Biology is an experimental science.

What is Principle 10?

Biology is a quantitative science.

What is Principle 11?

Biologists use models and simulations to test experimental predictions and convey their ideas; a model can be structural, mathematical, or physical.

What is Principle 12?

Biology affects our society.

What are the levels of biological organization from atoms to the biosphere?

Atoms, Molecules, Cells, Tissues, Organs, Organ systems, Organism, Population, Community, Ecosystem, Biosphere.

What are the two basic mechanisms of evolutionary change?

Vertical descent with mutation and horizontal gene transfer.

What do unity and diversity refer to in biology?

Unity refers to common characteristics shared by all life; Diversity refers to many different forms; evolution explains both.

When did life begin on Earth?

Between 3.5 and 4 billion years ago (bya).

What does vertical descent with mutation involve?

Transfer of genetic information from parents to offspring; new species evolve by accumulation of mutations; natural selection increases the frequency of beneficial mutations.

What is horizontal gene transfer?

Exchange of genetic material between organisms, sometimes across species; can be relatively rare but can spread traits like antibiotic resistance.

On which chromosome is the tuskless gene located in elephants?

The X chromosome.

Is the tuskless allele dominant or recessive?

Dominant (T).

What is the female tuskless genotype?

XTXt.

Why can't male elephants be tuskless?

Because a single T allele is lethal in males.

What are the three domains of life?

Bacteria, Archaea, and Eukarya.

How should scientific names be formatted?

Genus name is capitalized; species descriptor is not capitalized; both are italicized.

What is a hypothesis?

A proposed explanation for a natural phenomenon that is testable and falsifiable; it makes predictions that can be tested and is not proven.

What is a theory?

A broad explanation of an aspect of the natural world that is supported by a large body of evidence and can generate many predictions; DNA as genetic material is an example.

What are discovery-based science and hypothesis testing?

Two general scientific approaches: discovery-based science collects data without a preconceived hypothesis; hypothesis testing uses testable hypotheses to guide experiments.

What are the steps of the scientific method?

Observations → form a testable hypothesis → conduct experiments → analyze data → determine if the hypothesis is supported or rejected; experiments often include control and experimental groups.

What is a model in biology?

A conceptual, mathematical, or physical depiction of a real-world phenomenon used to convey ideas, evaluate experiments, and make predictions.

Why is biology considered a social discipline?

Biologists collaborate in labs, peer-reviewed publishing occurs, and science is discussed and debated in meetings and with teams (PI, students, postdocs, etc.).

Chapter 1.1 Summary

The study of life has revealed a set of unifying principles: cells are the simplest units of life; living organisms use energy, interact with their environment, maintain homeostasis; the genetic material (DNA) provides a blueprint for growth, development, and reproduction, populations of organisms evolve from one generation to the next, and all species (past and present) are related by an evolutionary history

Living organisms are studied at different levels of organization, spanning from atoms to the biosphere.

Chapter 1.2 summary

Modern forms of life are connected by an evolutionary history

Vertical descent with mutation is the primary way that evolution occurs

Horizontal gene transfer can also promote evolutionary change

Chapter 1.3 summary

The classification of living organisms allows biologists to appreciate the unity and diversity of life

Each species is placed into a taxonomic hierarchy, ranging from domain to species.

Chapter 1.4 summary

Biologists investigate life at a different levels of organization

A hypothesis is a proposed idea, whereas a theory is a broad explanation backed by extensive evidence

Discovery-based science and hypothesis testing are scientific approaches that help us understand biology

Model-based learning will enhance your understanding of biological concepts and improve your critical-thinking skills

Science is a social discipline