ireland3e_reproduction_ch18_fall11

ireland3e_reproduction_ch18_fall11 - 11/7/2011 Chapter 18...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
11/7/2011 1 Chapter 18 The Reproductive System: Maintaining the Species Sexual Reproduction Because we rely on sexual reproduction, having two genders is necessary to perpetuate the species Sexual reproduction involves choosing a mate based on phenotype and mixing and shuffling genes from the two to form a new individual this process mixes and blends the alleles in the gene pool, creating new genetic combinations these new combinations are essential to the survival of the species the genetic variation in populations of sexually reproducing organisms is the basis for adaptation of organisms to their environment “more fit” individuals will produce more offspring, thereby increasing the percentage of their alleles in the gene pool
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
11/7/2011 2 Gametes The main purpose of the reproductive system is to produce gametes egg and sperm and unite them to form a new individual A gamete is a general term for the reproductive cells that will form a new individual a haploid gamete means that the egg and sperm contain half the number of chromosomes of normal body cells these are produced via meiosis, a specialized type of cell division that ensures the equal and orderly division of chromosomes in order to form gametes properly, the normally diploid chromosome number must be cut in half, with the resulting gametes having exactly half the usual complement of alleles this way, when two haploid gametes unite to form a zygote, the original diploid number is restored Gametes In the male, meiosis occurs and four sperm are produced from two divisions of a primary spermatocyte Females produce only one egg from each round of meiosis, investing almost all of the cytoplasm and organelles in one gamete
Background image of page 2
11/7/2011 3 Gametes The Reproductive System Forming gametes is only one function of the reproductive system Other functions include triggering puberty maintaining reproductive ability stimulating secondary sex characteristics producing hormones involved in sexual maturation and general homeostasis
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
11/7/2011 4 The Male Reproductive System The function of the male reproductive system is to produce sperm, store it, and deliver it to the female reproductive system The male reproductive system is essentially one long tube, with sperm generated in the gonads at one end, matured along the route, and released from the body at the other end accessory glands add secretions to nourish and carry the sperm before it is released Sperm is produced in the testes The Male Reproductive System
Background image of page 4
11/7/2011 5 The Male Reproductive System The Male Reproductive System
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
11/7/2011 6 Spermatogenesis Each testis carries out spermatogenesis independently At puberty, spermatogenic cells are stimulated to begin producing sperm they first divide into spermatogonia spermatogonia in the walls of the seminiferous tubules divide, forming primary spermatocytes as these cells continue to divide, they are pushed farther from the wall of the tubule into the lumen, where they become secondary spermatocytes and then spermatids Spermatogenesis
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/26/2011 for the course BSC 2023 taught by Professor Staff during the Fall '08 term at FIU.

Page1 / 22

ireland3e_reproduction_ch18_fall11 - 11/7/2011 Chapter 18...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online