In the next section, we will take a closer look at this process.
They are all composed of the same cells.
Their genes are composed of DNA, and they carry out the same metabolic reactions to acquire energy and maintain their organization.
The first cell or cells are thought to be descended from the unity of life.
Charles Darwin came to the conclusion that the process that makes modification is possible.
Some aspect of the environment selects which traits are more likely to be passed on to the next generation during natural selection.
A biotic agent is part of the living environment, such as a deer, while an abiotic agent is part of the physical environment.
Natural selection selects for or against a new trait.
Competition, predation, and the physical environment can change the makeup of a population, favoring those more suited to the environment and lifestyle.
Natural selection is influenced by variations among the members of a population.
The deer prefer smooth leaves over hairy leaves, so the plant with hairy leaves has an advantage.
The plant with hairy leaves produces more seeds than most of its neighbors.
Most plants of this species produce hairy leaves later in life.
Although all individuals within a population have the ability to reproduce, not all do so with the same success, as was shown by this example.
When long-necked, but not short-necked, giraffes can reach their food source, or an inability to escape being eaten because long legs, but not short legs, can carry an object, are some of the factors that can prevent reproduction.
It can be seen that organisms with good genes can produce more offspring than those with bad genes.
Living organisms change over time and are passed on from one generation to the next.
The introduction of newer, more beneficial traits into a population can change a species.
New species can be created from existing ones.
The three domains of life are the diversity of life.
Existing organisms give rise to new ones.
The ancestors of all living organisms were a common ancestor about 4 billion years ago.
The prokaryotes are included in the domain Archaea and domain Bacteria.
Both single-celled and multicellular organisms have a nucleus.
A family tree is an evolutionary tree.
An evolutionary tree traces the ancestry of life on Earth to a common ancestor, just as a family tree shows how a group of people have descended from one couple.
One couple can have diverse children, and a population can be a common ancestor to several other groups, each adapted to a particular set of environmental conditions.
Over time, different life-forms have arisen.
Evolution is considered the unifying concept of biology because it explains so many aspects of it.
It's helpful to group organisms into categories because they are so diverse.
"usage" is the discipline of grouping organisms according to rules.
Taxonomy is meant to give valuable insight into evolution because of the variety of life on Earth.
Systematists learn more about living organisms.
Systematists use DNA technology to discover previously unknown relationships between organisms.
A group of interbreeding individuals is referred to as a model, kind.
There are more types of organisms in each category than in the preceding one.
The most closely related species in the same kingdom are the only ones that share general characteristics with one another.
The most distantly related species are placed in different domains.
The first common ancestor may have evolved from the domain Archaea.
archaea's cell walls and membranes are more similar to eukaryotes than tobacteria.
The Page 8 conclusion is that the archaeal line of descent split into two.
Archaea can live in environments that are too salty, hot, or acidic for most other organisms.
The environments may be similar to those of the primitive Earth and archaea.
"ancient" are the least evolved forms of life.
In the water, soil, and atmosphere, as well as on our skin and in our mouth and large intestine, are variously adapted to living.
The kingdoms were divided by the classification of domain Eukarya.
Some people need to acquire their food.
There are currently four kingdoms in the domain.
Plants, fungi, and animals evolved from protists.
Thekingdom Fungi include the familiar molds and mushrooms that help break down dead organisms.
The animals that are representative are aardvarks, jellyfish, and zebras.
The development of improved techniques in analyzing the DNA of organisms suggests that not all of the protists share the same evolutionary path.
There are five super groups for Eukarya.
The relationship and structure of these groups is being revised.
The structure of the supergroups will be explored in more detail in Section 21.1.
Biologists use a two-part name called a scientific name for living organisms.
Biologists use scientific names to avoid confusion.
Common names vary depending on locality and the language of the country.
Latin is a universally used language that is well known by most scholars.