Presentation on theme: "Cells - The Basic Unit of Life"— Presentation transcript:
1Cells - The Basic Unit of Life The characteristics of an organism in terms of a combination of inherited traits and reproduction.
2What are we trying to accomplish? Recognize that an individual organism does not live forever, therefore reproduction is necessary for the continuation of every species and traits are passed on to the next generation through reproduction.Describe that in asexual reproduction all the inherited traits come from a single parent.Describe that in a sexual reproduction an egg and sperm unite and some traits come from each parent, so the offspring is never identical to either of its parents.
3Why is reproduction important? Organisms do not live forever.If organisms did not reproduce everything would be extinct.Reproduction allows our traits to be passed on to the next generation.
4Traits that “Run in the family.” Hair colorA tendency to develop diseases, such as diabetes and some forms of cancer.Personality traits, such as shyness.Can you think of other traits that may be passed down?
5Two Kinds of Reproduction Asexual ReproductionSexual Reproduction
7Asexual ReproductionIn asexual reproduction, only one parent cell is needed for reproduction.The internal structures of the cell are copied by a process know as mitosis. The parent cell then divides, producing new cells that are exact copies of the parent cell.Most of the cells in your body divide this way.
85 forms of asexual reproduction BuddingBinary FissionVegetative propagationParthenogenesisFragmentation
9BuddingOccurs when offspring develops from a portion of the parent and pinches off to live independently. (i.e. Hydras - plants that live in freshwater ponds and streams)
10Binary FissionOccurs when a single-celled organism reproduces by splitting in two (i.e. Amoeba)
11Vegetative propagation Occurs when new plants are produced from sections of parent plants that are cut off (i.e. Geraniums, willow trees,and spider plants.)
12ParthenogenesisOccurs when certain animals produce eggs that develop directly into offspring without fertilization (insects, reptiles, fish)
13FragmentationOccurs when certain animals grow from a separate parent animal (star fish, flat worms)
15Sexual ReproductionIn sexual reproduction, two parent cells join together to form a new individual.The parent cells (aka sex cells) are different from ordinary body cells.Human body cells have 46 chromosomes (or 23 pairs).Male sex cells are called sperm.Female sex cells are called eggs.