主题七知识点梳理（Topic seven knowledge sorting）.docVIP

主题七知识点梳理（Topic seven knowledge sorting） This article is contributed by helloyu168 DOC documents may experience poor browsing on the WAP side. It is recommended that you first select TXT, or download the source file to the local view. Topic seven. Reproductive development and genetic knowledge of organisms. First, human reproduction and development. 1. The main male sex organ is the testis. The effect is to produce sperm and secrete androgens. 2. The main sex organ in women is the ovary. The effect is to produce eggs and secrete estrogen. 3. Sperm and egg cells are called fertilized eggs. Fertilization occurs in the fallopian tube. 4, new life begins at the fertilized egg, the gestation time is 40 weeks, 280 days or so. 5. Embryos and fetuses develop in the womb of the mother. The nutrients needed are obtained from the placenta and umbilical cord. Two. Reproduction and development of animals. 1. Complete metamorphosis of insects including four stages: eggs, larvae, pupae, and adults. Such as bees, butterflies, silkworms. For example: cocoons belong to the pupal stage. Incomplete metamorphosis of insects consists of three stages: egg nymph, adult. Like locusts and crickets. 2. Reproduction and development of amphibians: in vitro fertilization, fertilization occurs in water. The frogs development is fertilized eggs, tadpoles, frogs. Frogs call for courtship. The main stage, 3 birds of reproductive and developmental processes including: courtship, mating, nesting, spawning, hatching and brooding. The male peacock courtship behavior, Bai Juyis poem: a moment to ten, fear of hunger in the nest. Hard thirty days, the mother thin fat gradually. The brooding stage is described. Three. Heredity and variation of biology. 1. Heredity and variation are realized through reproduction and development. DNA is the major genetic material. The morphology and number of chromosomes in each biological cell is certain. Chromosomes exist in pairs in living cells. In reproductive cells, chro