S7L3. Obtain, evaluate, and communicate information to explain how organisms reproduce either sexually or asexually and transfer genetic information to determine the traits of their offspring. a. Construct an explanation supported with scientific evidence of the role of genes and chromosomes in the process of inheriting a specific trait b. Develop and use a model to describe how asexual reproduction can result in offspring with identical genetic information while sexual reproduction results in genetic variation. (Clarification statement: Models could include, but are not limited to, the use of monohybrid Punnett squares to demonstrate the heritability of genes and the resulting genetic variation, identification of heterozygous and homozygous, and comparison of genotype vs. phenotype.) c. Ask questions to gather and synthesize information about the ways humans influence the inheritance of desired traits in organisms through selective breeding. (Clarification statement: The element specifically addresses artificial selection and the ways in which it is fundamentally different from natural selection.)
Living organisms GROW & DEVELOP Change over an individual’s life time * Grow – means to get bigger * Develop – means to mature, become more complex SO THEY CAN REPRODUCE
Living organisms REPRODUCE Make clones or similar copies of yourself * Asexual reproduction – involves one parent - mitosis * Sexual reproduction – involves two parents - meiosis
Terms You Need to Know Somatic Cells (body cells) – cells that take part in the formation of the body, becoming differentiated/specialized into the various tissues, organs, etc.; reproduce by mitosis. Germ Cells – cells that produce mature gametes through meiosis. Gametes (sex cells) – a mature sexual reproductive cell, as a sperm or ovum (egg), that unites with another cell to form a new organism.
How do little elephants grow up to be BIG elephants?
Why do animals shed their skin?
Mitosis/Cell Division Asexual Reproduction Mitosis/Cell Division Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals? 7
The process of asexual reproduction begins in humans after a sperm fertilizes an egg.
Three reasons why cells reproduce by asexual reproduction: 1. Growth 2 Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement Skin cancer - the abnormal growth of skin cells. Cells are unable to control their cycles of cell division. Cells spend very little time in interphase. This most often develops on skin exposed to the sun.
The Cell Cycle (The Life of a Cell) Phases include: Interphase (G1, S, G2)– Preparation phases for mitosis; a period of resting, growth, and DNA replication. Mitosis – Nucleus division/asexual reproduction Cytokinesis – separation of the cytoplasm
The Cell Cycle (The Life of a Cell) G0 Phase (Resting) Interphase G1 Phase (Growth) S Phase (DNA Synthesis/replication) G2 Phase (Growth and DNA checkpoint)
The Cell Cycle (The Life of a Cell) Mitosis Prophase Metaphase Anaphase Telophase P M A T
Duplicating Genetic Information
Duplicating Genetic Information
Animated Mitosis Cycle http://www.cellsalive.com/mitosis.htm Phases of Mitosis Prophase Metaphase Anaphase Telophase
Cytokinesis
The Cell Cycle 26
Cell Cycle
Mitosis Animation http://www.cellsalive.com/mitosis.htm
S7L3. Students will recognize how biological traits are passed on to successive generations. Explain the role of genes and chromosomes in the process of inheriting a specific trait. B. Compare and contrast that organisms reproduce asexually and sexually (bacteria, protists, fungi, plants, and animals). C. Recognize that selective breeding can produce plants or animals with desired traits.
Review
Interphase occurs before mitosis begins Period of growth and developement Chromosomes are copied (# doubles) Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase CELL MEMBRANE Nucleus Cytoplasm
Cells spend most of their lives in this phase of the cell cycle Interphase Plant Cell Animal Cell Cells spend most of their lives in this phase of the cell cycle
Prophase 1st step in Mitosis Mitosis begins with the disintegration of the nuclear membrane and the appearance of chromosomes Centrioles (or poles) appear and begin to move to opposite end of the cell. Spindle fibers form between the poles. Centrioles Sister chromatids Spindle fibers
Prophase Plant Cell Animal Cell
Metaphase 2nd step in Mitosis Chromatids (or pairs of chromosomes) attach to the spindle fibers. Chromatids line up along the metaphase plate. Centrioles have completely move to poles of the cell. Centrioles Spindle fibers
Metaphase Plant Cell Animal Cell
Anaphase 3rd step in Mitosis Chromatids (or pairs of chromosomes) separate at the centromere and begin to move to opposite ends of the cell. Spindle fibers shorten. Centrioles Spindle fibers
Anaphase Plant Cell Animal Cell
Telophase 4th step in Mitosis Reformation of the nuclear membrane. Chromosomes uncoil to form chromatin. Cell membrane begins to pinch in. Nuclei Nuclei Chromatin
Telophase Plant Cell Animal Cell
Cytokinesis occurs after mitosis Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.
Animal Cell Cycle -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
Plant Cell Cycle -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis