Types of Reproduction Development Sexual Reproduction n The

+ Types of Reproduction & Development

+ Sexual Reproduction n The fusion of reproductive cells from two separate individuals to form a new offspring. n Offspring produced by sexual reproduction inherit some of their genetic information from each parent. Parent Offspring

+ Internal vs. External Fertilization n Internal Fertilization occurs inside the body.

+ Internal vs. External Fertilization n External Fertilization occurs outside the body.

+ Internal vs. External Fertilization REMINDER!!! Sperm + Egg Zygote = “the fertilized egg”

+ Internal vs. External Development n Internal Development occurs inside the body of the mother.

+ Internal vs. External Development n External Development occurs outside the body of the mother.

+ Human Development n Differentiation: Point in human development where certain genes turn on and others turn off. n This causes different cells to develop special functions (Specialization).

+ TWINS!!! n Fraternal Twins – two eggs released during ovulation and both are fertilized by different sperm producing two different embryos. n Identical Twins – one egg is released and is fertilized by one sperm, but the zygote splits in half producing two identical embryos.

+ Asexual Reproduction n The production of two genetically identical offspring from a single parent n Single-celled organisms can ONLY reproduce asexually n No sperm or egg cell involved Parent Offspring

+ Types of Asexual Reproduction n Binary Fission (amoeba)

+ Types of Asexual Reproduction n Budding (Hydra)

+ Types of Asexual Reproduction n Regeneration

+ Cell Division Mitosis & Meiosis

+ Cell Division Vocabulary Words n DNA – carries the genetic information of the cell n Nucleus – stores DNA n Chromosomes – threadlike structure of condensed DNA that contains an individual’s genes n Homologous Pair – a pair of matching chromosomes, one inherited from each parent n 23 homologous pairs in humans = 46 total chromosomes

+ Homologous Chromosomes

+ Cell Division Vocabulary Words n Diploid – number of chromosomes in all somatic cells (2 n) n For humans, diploid is 46 n Haploid n – number of chromosomes in all gametes (n) For humans, haploid is 23 n Parent Cell- what you start with n Daughter Cell – the product n Somatic Cell – a body cell. Any cell other than egg/sperm n Gamete – a sex cell (egg or sperm)

+ Mitosis Making exact copies of cells (Cell Division)

+ Mitosis n. Purpose: growth and repair n. One diploid parent cell produces two identical diploid daughter cells. n. Mitosis = Asexual Reproduction of cells

+ Meiosis Making sex cells (sperm and egg)

+ Meiosis n. Purpose: making gametes n. One diploid parent cell produces four different haploid daughter cells. n Each daughter cell is unique and different from the parent cell AND the other daughter cells.

+ Meiosis n. Also called “gametogenesis” n. Males = Make 4 Sperm Cells n. Females = Make 1 Egg Cell & 3 Polar Bodies

+ Crossing Over n During Meiosis, some information on the chromosomes may switch between homologous pairs. n This results in genetic variation.

+ Human Development

+ Interphase DNA duplication occurs to prepare for cell division.

+ Prophase DNA forms into chromosomes and centrioles move to opposite ends of nucleus.

+ Metaphase Chromosomes line up in center of cell and spindle fibers from centrioles attach.

+ Anaphase Chromosomes begin moving towards opposite ends of nucleus (pulled by centrioles).

+ Telophase Chromosomes reach opposite sides and cleavage occurs, forming two identical daughter cells.

Mitosis +

Mitosis +