Summary of Lessons So Far
Biology is the science of life. All living organisms share several key properties such as order, sensitivity or response to stimuli, reproduction, growth and development, regulation, homeostasis, and energy processing.
Living things are highly organized parts of a hierarchy that includes atoms, molecules, organelles, cells, tissues, organs, and organ systems. Organisms, in turn, are grouped as populations, communities, ecosystems, and the biosphere.
The great diversity of life today evolved from less-diverse ancestral organisms over billions of years. A diagram called a phylogenetic tree can be used to show evolutionary relationships among organisms.
Biology is very broad and includes many branches and subdisciplines. Examples include molecular biology, microbiology, neurobiology, zoology, and botany, among others.
Glossary of Words
smallest and most fundamental unit of matter
study of the chemistry of biological organisms
collection of all the ecosystems on Earth
study of plants
smallest fundamental unit of structure and function in living things
set of populations inhabiting a particular area
all the living things in a particular area together with the abiotic, nonliving parts of that environment
organism with cells that have nuclei and membrane-bound organelles
process of gradual change during which new species arise from older species and some species become extinct
ability of an organism to maintain constant internal conditions
large molecule, typically formed by the joining of smaller molecules
study of the structure and function of microorganisms
chemical structure consisting of at least two atoms held together by one or more chemical bonds
study of biological processes and their regulation at the molecular level, including interactions among molecules such as DNA, RNA, and proteins
study of the biology of the nervous system
collection of related tissues grouped together performing a common function
level of organization that consists of functionally related interacting organs
small structures that exist within cells and carry out cellular functions
individual living entity
study of life’s history by means of fossils
diagram showing the evolutionary relationships among various biological species based on similarities and differences in genetic or physical traits or both; in essence, a hypothesis concerning evolutionary connections
all of the individuals of a species living within a specific area
single-celled organism that lacks organelles and does not have nuclei surrounded by a nuclear membrane
group of similar cells carrying out related functions
study of animals