Introduction to Biology: The Study of Life

Flashcards covering the fundamentals of biology, including species diversity, taxonomy, levels of organization, characteristics of life, and regulatory mechanisms.

How many species have been formally named by scientists?

Approximately $1.8 \text{ million}$ species.

What is the estimated total number of species existing on Earth today?

Between $30 \text{ to } 100 \text{ million}$ species.

What percentage of species that have ever lived are now extinct?

$99\%$ of species.

What are the components and formatting rules for a scientific name?

It consists of a Genus name (capitalized) and a specific epithet (lower case); the entire name must be italicized or underlined.

In a phylogenetic tree, what does the length of the lines represent?

Genetic distance, which is the degree of difference in DNA sequence between any two pairs.

What are the three Domains of life?

Eukarya, Eubacteria, and Archaea.

How is life defined in an organismic state?

A state characterized by the capacity for metabolism, growth, reaction to stimuli, and reproduction.

What is the hierarchy of biological organization from the largest to the smallest scale?

Biosphere, Ecosystem, Community, Population, Organism, Organ system, Organ, Tissue, Cell, Organelle, Molecule, Atom.

What are emergent properties in the hierarchy of life?

New properties that arise at each step upward in the hierarchy from the arrangement and interactions among component parts.

What are the eight characteristics of life mentioned in the notes?

1. Organization, 2. Order, 3. Reproduction, 4. Growth and development, 5. Energy utilization, 6. DNA (genetic information), 7. Regulation, 8. Evolution.

What is the definition of homeostasis?

The maintenance of physiological conditions between acceptable limits.

What are the three examples of biological processes regulated by feedback mechanisms?

Metabolic pathways, the cell cycle, and gene expression.

How is negative feedback defined, and what are some examples?

It occurs when changes in the output have an opposite effect on the process; examples include cruise control, pH regulation in blood, and body temperature regulation.

How is positive feedback defined, and what are some examples?

It occurs when changes in the output promote further changes in the same direction; examples include blood clotting, contractions at childbirth, and signaling cascades.

What is the function of the enzyme ATP synthase?

It is responsible for producing energy ($ATP$) in cells.

What specific example of architecture is used to show the unity underlying the diversity of life?

The architecture of eukaryotic cilia.

Who published 'The Origin of Species' in $1859$?

Charles Darwin ($1809–1882$).