Seventh grade science textbooks typically focus on life science, according to About.com and the California Department of Education. Life science includes topics such as cell biology, genetics, climate and weather, as well as the properties of water.
The Next Generation Science Standards determine the content taught at each grade level, as of 2015. The unit on cells in most seventh grade science textbooks covers the functions of each part of a cell, the differences between plant and animal cells, how cells create energy and how cells divide. The unit on genetics covers basic genetic traits and properties, such as sexual and asexual reproduction, basic DNA structures and the differences between dominant and recessive genes.
In addition to genetics, seventh grade science textbooks usually cover evolution. This unit focuses on natural selection and the supporting evidence for evolution, as well as Darwin's initial reasoning behind the theory. Another life science unit in these textbooks concerns the study of ecosystems.
Despite the focus on life science, most seventh grade textbooks also include a section on earth science. This section concerns geological processes, rock cycles and rock types, and how geology affects living organisms. There is also typically a section on physical science, such as the study of light and movement.