Stephanie'sChapter6

__ Chapter 6 Continuity Through Reproduction __ __ Reproduction (6.1-6.5 p135-p143) __ Life cycle - all events that occur between the beginning and end of an organism’s life Sexual reproduction – reproduction involving the contribution of genetic material from two parents Gametes – the sex cells (sperm and ova – formed by meiosis) Asexual reproduction – is where a new organism is formed from one parent, usually involves the parent dividing in two (or more)  · Some organisms are capable of both (ex: potatoes plants reproduce sexually but it you take the potato itself and let it grow buds/sprouts this is asexual; sea stars can regenerate from a single arm, or sexual with each other) Sperm cells – the male gamete cell Ova – the female gamete cell Fertilization – when the nuclei of two gametes (one female and one male) unite and make an egg Zygote – the diploid product of the gamete cells uniting or the fertilized egg Haploid Cells – a cell containing only one member of each chromosome pair (n) of a species(half the DNA need for normal diploid cells) Diploid Cells – a cell containing both members of every chromosome pair characteristics of a species(2n) Meiosis – the process that makes gamete cells (see videos on meiosis page for better explanation) Chromatid – on of two strands of a replicated chromosome before separation during mitosis or meiosis Centromere – the specialized region of a chromosome that holds two replicated chromosomal strands together and that the attaches to the spindle in mitosis Crossing-over – during prophase 1 of meiosis, the breakage and exchange of corresponding segments of chromosome pairs at one or more sites along their length, resulting in genetic recombination __ The Human Reproductive System (6.6-68. p146-p152) __ Testes – male reproductive organs Ovaries – female reproductive organs Embryo – an organism at its earliest state of development Hormones – a substance, secreted by cells or glands, that has a regulatory effect on cells and organs elsewhere in the body; a chemical messenger Feedback system – a relationship in which one activity of an organism affects another, which in turn affects the first, yielding a regulatory balance Menstrual cycle – the female reproductive cycle that is characterized by regularly recurring changes in the uterine lining Uterus – a muscular, pear shaped organ in the female pelvis where a fetus develops Hypothalamus – a specialized part of the base of the brain that in humans combines neuron and hormone activity; it links that autonomic nervous system with the endocrine system in regulates many body functions Pituitary – endocrine gland attached to the base of the brain, consisting of an anterior and a posterior lobe Estrogen – the hormone that stimulates the development of a female secondary sexual characteristics(breasts, hips, and additional hair) Progesterone – a female hormone secreted by corpus luteum of the ovary and by the placenta that acts to prepare and maintain the uterus for pregnancy and to prepare the breast s for lactation *Only one sperm fertilizes one ovum* Semen – the thick fluid in which sperm are transported in mammalian males *Sperm can live for 48 hours an ovum only 24 hours*
 * Female Reproductive System  ||   Male Reproductive System   ||
 * [[image:female_reproductive_system.jpg width="251" height="260"]] ||   [[image:male.jpg width="373" height="310"]]  ||