Biologyis the science of life. Biologists study the structure, function, growth, origin, evolution and distribution of living organisms. There are generally considered to be at least nine “umbrella” fields of biology, each of which consists of multiple subfields.
Biochemistry: the study of the material substances that make up living things
Botany: the study of plants, including agriculture
Cellular biology: the study of the basic cellular units of living things
Ecology: the study of how organisms interact with their environment
Evolutionary biology: the study of the origins and changes in the diversity of life over time
Genetics: the study of heredity
Molecular biology: the study of biological molecules
Physiology: the study of the functions of organisms and their parts
Zoology: the study of animals, including animal behavior
Adding to the complexity of this enormous idea is the fact that these fields overlap. It is impossible to study zoology without knowing a great deal about evolution, physiology and ecology. You can’t study cellular biology without knowing biochemistry and molecular biology as well.
Genetics is the study of how heritable traits are transmitted from parents to offspring. Humans have long observed that traits tend to be similar in families. It wasn’t until the mid-nineteenth century that larger implications of genetic inheritance began to be studied scientifically.
In 1858, Charles Darwin and Alfred Russell Wallace jointly announced their theory of natural selection. According to Darwin’s observations, in nearly all populations individuals tend to produce far more offspring than are needed to replace the parents. If every individual born were to live and reproduce still more offspring, the population would collapse.
Overpopulation leads to competition for resources.Darwin observed that it is very rare for any two individuals to be exactly alike. He reasoned that these natural variations among individuals lead to natural selection. Individuals born with variations that confer an advantage in obtaining resources or mates have greater chances of reproducing offspring who would inherit the favorable variations.