Genealogy is the study of family descent — how one person is related to their parents,祖父母，cousins and more.Many people are interested in tracing their genealogy to discover where their family came from.他们可能还想找到与他们有关系的其他人。But genealogy also applies to species beyond us humans.A person can study the genealogy of a dog or horse,for instance.That information can be useful in events such as dog vwin手机shows and horse races.系谱学也可以帮助科学家追踪现代物种是如何进化的。
Genealogists — people who study genealogy — may construct family trees as they work.These branching drawings help them track who is related to whom.This can be done by searching through historical records that can record when people were born,married or died.Now,though,people can also learn about their family history by getting their DNA analyzed.DNA分子在父母之间传递。这意味着DNA可以为人们的关系提供线索。A number of DNA screening companies today help people find relatives they might not have known about.They also can help people figure out where in the world their families may have come from.
Now,任何人都可以把他们的口水送到一家家谱公司分析他们的DNAto tell them who they might be related to.
DNA（脱氧核糖核酸的简称）长的，大多数活细胞内的双链螺旋形分子，携带遗传指令。它建立在磷的主链上，oxygen,and carbon atoms.在所有生物中，从动植物到微生物，these instructions tell cells which molecules to make.
发展(adj.evolving) To change gradually over generations,或者很长一段时间。In living organisms,这种进化通常涉及到基因的随机变化，然后这些变化将传递给个体的后代。这些会导致新的特征，比如变色，new susceptibility to disease or protection from it,or different shaped features (such as legs,antennae,toes or internal organs).如果非生物随着时间的推移而改变，它们也可能被描述为进化的。例如，the miniaturization of computers is sometimes described as these devices evolving to smaller,more complex devices.
familyA taxonomic group consisting of at least one genus of organisms.
genealogyThe study of ancestry records and other aspects of a family's history.People who work in this field are known as genealogists.
一代一组（在任何物种中）同时出生或被视为一个群体的个体。你的父母属于你家的一代人，例如，还有你的祖父母。Similarly,you and everyone within a few years of your age across the planet are referred to as belonging to a particular generation of humans.The term also is sometimes extended to year classes of other animals or to types of inanimate objects (such as electronics or automobiles).
分子An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound.分子可以由单一类型的原子或不同类型的原子组成。For example,空气中的氧由两个氧原子组成（O2),但是水是由两个氢原子和一个氧原子组成的（H2o）。
speciesA group of similar organisms capable of producing offspring that can survive and reproduce.