Inquiring About Life
Evolution is the process of change that has transformed life from its beginnings to the astounding
array of organisms today.
Studying the diverse forms of life reveals common themes
The biosphere consists of all life on Earth and all the places where life exists: most regions of land,
most bodies of water, the atmosphere to an altitude of several kilometers, and even sediments far
below the ocean floor.
An ecosystem consists of all the living things in a particular area, along with all the nonliving
components of the environment with which life interacts, such as soil, water, atmospheric gases, and
light.
Communities are array of organisms inhabiting a particular ecosystem.
A population consists of all the individuals of a species living within the bounds of a specified area.
Organisms are individual living things
The organs of complex animals and plants are organized into organ systems, each a team of organs
that cooperate in a larger function. Organs consist of multiple tissues
Tissues are groups of cells that work together, performing a specialized function.
The cell is life’s fundamental unit of structure and function.
Organelles are the various functional components present in cells.
Molecules are chemical structures consisting of two or more atoms.
Emergent properties are novel properties emerge that are absent from the preceding one.
Systems biology is the exploration of a biological system by analyzing the interactions among its
parts.
A eukaryotic cell contains membrane-enclosed organelles.
A prokaryotic cell lacks a nucleus or other membrane-enclosed organelles.
DNA is deoxyribonucleic acid.
Each chromosome contains one very long DNA molecule with hundreds or thousands of genes, each
a stretch of DNA arranged along the chromosome.
Gene expression is the process by which the information in a gene directs the manufacture of a
cellular product
Genome is the entire library of genetic instructions that an organism inherits.
Genomics are whole sets of genes in one or more species.
Bioinformatics is the use of computational tools to store, organize, and analyze the huge volume of
data that results from high-throughput methods.
1.2 Evolution accounts for the unity and diversity of life
Bacteria are the most diverse and widespread prokaryotes and are now classified into multiple
kingdoms. Each rod-shaped structure is called a bacterial cell.
Some of the prokaryotes known as archaea live in Earth’s extreme environments, such as saltly lakes
and boiling hot springs. Domain archaea includes multiple kingdoms. Each round structure is called
an archaeal cell.
All the eukaryotes are grouped in the domain eukarya.
Kingdom plantae consists of terrestrial multicellular eukaryotes, land plants, which carry out
photosynthesis, the conversion of light energy to the chemical energy in food.
Kingdom fungi is defined in part by the nutritional mode of its members, which absorb nutrients
from outside their bodies.
Kingdom animalia consists of multicellular eukaryotes that ingest other organisms.
Protists are mostly unicellular eukaryotes and some relatively simple multicellular relatives.