Presentation on theme: "Connect! What are the green cells? The big gold cell?"— Presentation transcript:
1Connect! What are the green cells? The big gold cell? What process is shown?
2Part 2: Fertilizationnnis the union of a monoploid sperm nucleus and a monoploid egg nucleus producing a fertilized egg called a zygote2nzygote2nmitosis?
3A diploid zygote is produced and the species number of homologous chromosomes (2n) is restored. For ex, when a sperm cell of a fruit fly containing 4 chromosomes joins with an egg cell of a fruit fly containing 4 chromosomes, the resulting zygote has 8 chromosomes.
4There are two types of fertilization: external and internal.
5A. EXTERNAL FERTILIZATION when gametes fuse (join) outside of female’s bodyoccurs in many aquatic vertebrae such as fish and amphibians (toad photos)usually large numbers of eggs are required to insure species survival
6A. INTERNAL FERTILIZATION when gametes fuse in the moist reproductive tract of the femaleoccurs in most terrestrial (land) vertebrae animalsfewer eggs
7Chunk Define fertilization. What is the fertilized egg called? Is the fertilized egg haploid or diploid?What are the two types of fertilization?What type of organisms carry out external fert?What type of organisms carry out internal fert?Which type of fert usually produces few eggsWhy?What does the term “terrestrial” mean?
8ConnectThe series of changes which occurs as a living thing reaches its final form is called development. These chicks went through many changes during their development before they hatched. They will continue to change as they develop into adult penguins.What changes have you gone through during the course of your development? Are you still going through the developmental process? How does a zygote turn into a baby, then an adult?
9PART 3: Embryonic Development The Steps of Development The zygote starts dividing by mitosis. This is called cleavage. At this point, the zygote becomes an embryo.The embryo forms a blastula, which is a single layer of cells in a hollow-ball type structure.Arrow is where sperm entered
10When one side of the blastula becomes indented the gastrula is formed, which has 3 layers: endoderm – inner layermesoderm – middle layerectoderm – outer layer
114. Gastrulation (forming a gastrula) is a very important part of development bc it is now when the cells of each layer differentiate, meaning they each get a specific job. Each cell becomes part of the various organs and systems of the multicellular animal.Review!How does each cell turn into a different type?How do we end up with neurons, white blood cells, etc…?
12DifferentiationEndoderm – becomes the linings of the digestive and respiratory tracts, parts of the liver and pancreas (guts)Mesoderm – becomes muscle, circulatory system, skeleton, excretory system, and gonadsEctoderm – becomes nervous system and skin5. Growth is an increase in cell number as well as cell size.
13Chunk! Define zygote cleavage. Does it involve meiosis or mitosis? Explain.When does the zygote become an embryo?What is a blastula?What is a gastrula?Name the 3 layers of a gastrula, and what each layer differentiates into.What is gastrulation?Identify all of the parts of this diagram:Explain how genes influence differentiation.What are 2 ways growth can occur?