Cellular Division & Reproduction

These are human chromosomes taken from a scanning electron microscope (SEM).

Karyotyping Chart of metaphase chromosomal pairs arranged according to length and location of centromere; used to pinpoint unusual chromosome numbers in cells.

Autosomes Sex chromosomes

Mitosis (vs) Meiosis

Mitosis VS Meiosis Diploid (2n) Somatic Cells (Body Cells) For growth, repair, and asexual reproduction Haploid (n) Gametes (Sex Cells in ovaries or testes) For sexual reproduction.

Animation: http://www.cellsalive.com/cell_cycle.htm Mitotic Cell Cycle Animation: http://www.cellsalive.com/cell_cycle.htm

REPRODUCTION Two Types: Sexual-two haploid gametes combine to produce a genetically unique, new individual. Asexual-a single parent reproduces an exact genetic copy or copies of itself.

Types of Asexual Reproduction Binary fission – simple division

Types of Asexual Reproduction Budding – organism grows off of body of parent. Yeast Unicellular Hydra Multicellular

Budding is part of the life cycle of many Cnidarians (jellyfish and their relatives).

Types of Asexual Reproduction Vegetative propagation – plant grows from cuttings or out of parent plant.

Types of Asexual Reproduction Parthenogenesis – egg develops without fertilization. The asexual, all-female whiptail species Cnemidophorus neomexicanus (center), which reproduces via parthenogenesis, is shown flanked by two sexual species having males, C. inornatus (left) and C. tigris (right), which hybridized naturally to form the C. neomexicanus species Komodo Dragon, Varanus komodoensis, is confirmed to be able to reproduce naturally by parthenogenesis

Types of Asexual Reproduction Fragmentation and regeneration – offspring grow from cut off part of parent.

Some regeneration is NOT reproduction

Types of Asexual Reproduction Spore formation – production of a mitotic, asexual reproductive cell.

Types of Sexual Reproduction External fertilization – sperm is released into environment in vicinity of eggs.

More external fertilization

Types of Sexual Reproduction Conjugation – Two cells line up and exchange genetic material.

Types of Sexual Reproduction Pollination – pollen containing sperm are transferred to female portion of flower containing ovum (eggs). Pollen on anther Flower anatomy Pollen collecting on honey bee

Types of Sexual Reproduction Internal fertilization – male sperm is placed inside female. + = Learn from this…wait until you’re Married!!

Sexual Reproduction Terminology Sperm – male, haploid gamete, usually smaller and more mobile

Sexual Reproduction Terminology Egg – female haploid gamete, usually larger, less mobile, containing food source for embryo.

Sexual Reproduction Terminology Fertilization – joining of male and female gametes.

Sexual Reproduction Terminology Zygote – fertilized egg. This is the first of five images showing that eggs from the sea urchin Lytechinus pictus (large eggs) are preferentially fertilized by sperm from the same species. A fertilization membrane forms around the eggs of L. pictus; however, eggs from a different sea urchin species, Strongylocentrotus purperatus, are not fertilized.

Sexual Reproduction Terminology Embryo – early developing offspring prior to birth.

Sexual Reproduction Terminology Fetus – later developing offspring prior to birth. ../../../../Biology/Bio%20Graphics/fetal_8_weeks_fetus_circle_s1.jpg