Animal Reproduction and Development Reproduction Song
Animals reproductive by asexual and sexual methods: • Asexual is the production of offspring with genes all from one individual, without the fusion of gametes. • Sexual involves formation of gametes and fertilization, genetic variation Asexual Methods Include: Budding in Hydra Starfish Regeneration Gemmules in Sponges
Parthenogenesis: an unfertilized egg develops Honey bees: drones are males and are produced parthenogeneticly and female workers and queens form from fertilized eggs. Queen Worker (female) Drone (male)
Sexual Reproduction Hermaphroditism: individual has both male and female reproductive systems Earthworm
Fertilization can occur externally or internally Aquatic animals tend to be external Terrestrial animals tend to be internal Development can be external in the water, external on land, or internal. Oviparous: lay eggs, Amniotic eggs are terrestrial eggs Ovoviparous: live birth from eggs (some sharks and snakes) Viviparous: live placental birth
What are the adaptive values of each style off sexual animal reproduction? Number of Eggs: ? Parental Care: ? Habitat: ? Introduction to Reproduction System
Reproductive System of the Human Male Male Reproductive System video Male Reproductive System detailed video
The male reproductive system produces sperm cells and provides a mechanism for delivering them to the female's body. Identify the role of: Testes Epididymis Vas deferens Scrotum
Outline the functions of the male reproductive organs Vasectomy Surgery video
Spermatogenesis Meiosis produces gametes in the seminiferous tubules.
Seminiferous Tubules synthesize sperm Sperm cells Sperm Structures
Female Reproductive System Female Reproductive System video
Oogenesis This is the state of the egg when fertilized
Stages of Development in the Ovary Ovarian Cycle video
Identify the stages of the cycle What happens in the ovary, uterus, and pituitary glands? Uterine Cycle video Menopause: cessation of cycle, ages 46-54, ovaries lose response to FSH & LH
Cleavage occurs over several days following fertilization. The zygote divides as it travels through the oviduct. By the time the cilia of the oviduct deliver the embryo to the uterus, the embryo is a ball of cells called a blastocyst. The blastocyst implants in the endometrium.
A blastocyst forms nearly a week after fertilization Four membranes protect and nourish the embryo, which consists of three tissue layers.
Nutrients and waste products are exchanged between the fetus and the mother within the placenta. The umbilical vein (red) carries oxygen-rich blood and nutrients to the fetus. The umbilical arteries are blue, indicating that they carry oxygen-depleted blood and waste products away from the fetus.
Placental circulation: materials are exchanged by diffusion, active transport, and selective absorption. Not by direct blood contact. Structure and function of the placenta video
Human fetal development: Amniotic Sac 5 weeks 14 weeks 20 weeks Blood Incompatibility video
Name the phases and state of the organs. Name the hormones: Black: Red: Blue: Green:
Animal Development Epigenesis: animal emerges gradually from the egg Preformation: shows infant in sperm from 1694 engraving “homunculus”
Fertilization in Mammals Zona pellucida Changes that occur in the egg after fertilization video
Cleavage partitions the zygote into many smaller cells Rapid cell division without growth produces cells called blastomeres.
In both sea urchins and frogs first two cleavages are vertical. • The third division is horizontal. • The result is an eight-celled embryo with two tiers of four cells.
A blastocoel forms within the morula blastula View the sea urchin development video on the CD
Gastrulation rearranges the blastula to form a three-layered embryo with a primitive gut Development after fertilization video
Organogenesis forms the organs from the three embryonic germ layers Organogenesis in a frog embryo View frog development video on CD
Amniote embryos develop in a fluid-filled sac within a shell or uterus • The amniote embryo is an adaptation for reproduction in the terrestrial environment. • Shelled eggs of reptiles and birds. • Uterus of placental mammals.
Extraembryonic membranes in a chick Identify the membranes that provide supporting functions Protection from mechanical shock Gas exchange Disposal of uric acid Nutrient source
Extraembryonic membranes in a chick How extraembryonic membranes support chick video
The four extraembryonic membranes are the yolk sac, amnion, chorion, and allantois. Cells of the yolk sac digest yolk providing nutrients to the embryo. The amnion encloses the embryo in a fluid-filled amniotic sac which protects the embryo from drying out. The chorion cushions the embryo against mechanical shocks. The allantois functions as a disposal sac for uric acid.
Chick embryo 54 hours old Most major organs have formed Formation of structures in embryo video
Embryonic membranes – homologous with those of shelled eggs. • Chorion: completely surrounds the embryo and other embryonic membranes. • Amnion: encloses the embryo in a fluid-filled amniotic cavity. • Yolk sac: found below the developing embryo. • Develops from the hypoblast. • Site of early formation of blood cells which later migrate to the embryo. • Allantois: develops as an outpocketing of the embryo’s rudimentary gut. • Incorporated into the umbilical cord, where it forms blood vessels. • Organogenesis begins with the formation of the neural tube, notochord,and somites.