Chapter 14: History of Life

Holt Modern Biology Vocab

Biogenesis

all living things come from other living things

Spontaneous Generation

idea that living things come from nonliving things

Radiometric Dating

the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products

Isotopes

atoms of the same element that have different numbers of neutrons

Mass Number

the sum of the number of neutrons and protons in an atomic nucleus

Radioactive Decay

the release of particles or radiant energy by the unstable nuclei of some isotopes

(Process)

Radioactive Isotopes

Atoms that are unstable, meaning they decay, or break down, to form stable atoms of a different element

Half-life

The length of time it takes for one-half of any size sample of an isotope to decay to a stable form.

Microspheres

spherical in shape and are composed of many protein molecules that are organized as a membrane

Coacervates

collection of droplets that are composed of lipids, amino acids, and sugars

Ribozyme

RNA molecule capable of acting as an enzyme.

Archaea

Single-celled, no nucleus, Live in harsh condisions, oldest organisms on earth

Chemosynthesis

process by which some organisms, such as certain bacteria, use chemical energy to produce carbohydrates

Cyanobacteria

Predominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll

Mmm..Spaghetti!

Ozone

a form of oxygen that has three oxygen atoms in each molecule instead of two. protects us from dangerous ultraviolet radiation from the sun

Endosymbiosis

Process through which early prokaryotic cells are thought to have engulfed other, smaller cells and eventually incorporated them as organelles; these cells evolved into modern-day eukaryotes.