Types of Reproduction & Development

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

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

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

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

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

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

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

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

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

Types of Asexual Reproduction Binary Fission (amoeba)

Types of Asexual Reproduction Budding (Hydra)

Types of Asexual Reproduction Regeneration

Cell Division Mitosis & Meiosis

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

Homologous Chromosomes

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

Mitosis Making exact copies of cells (Cell Division)

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

Meiosis Making sex cells (sperm and egg)

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

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

Crossing Over During Meiosis, some information on the chromosomes may switch between homologous pairs. 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