Lesson 6 - Biology 2

• Asexual reproduction - Mode of reproduction that does not involve the use of gametes or sex cells.
• Sexual reproduction - Mode of reproduction that involves the use of gametes or sex cells.
• Fission 

  Type of asexual reproduction involving the division of body into two or more equal parts.
• Budding

  Type of asexual reproduction where a new individual arises as an outgrowth (bud) from its parent, develops organs like those of the parent, and then detaches itself.
• Fragmentation

  • Type of asexual reproduction where the body breaks into two or more parts, with each fragment capable of becoming a complete individual; 
• Sporulation 

  • Type of asexual reproduction where a new individual forms from an aggregation of cells surrounded by a resistant capsule or spore, which later on germinates. 
• Isogamy 

  • Fusion of similar gametes which are usually motile. It may involve either flagellated gametes (as in the case of Chlamydomonas) or non-flagellated cells or structures (as in the case of Spirogyra). 
• Heterogamy 

  Fusion of dissimilar gametes. In oogamy, a large immotile gamete, the egg is fertilized by a small motile gamete, the sperm.
•  Bisexual reproduction

  Type of sexual reproduction involving the union of gametes from two genetically different parents.
• Hermaphrodite

  An individual with both male and female reproductive tissues. In animals “self-fertilization” is not common.
• Development

  • involves formation of sex cells, zygote formation, subsequent stages in one’s life span. 
• Gametogenesis - Stage of development that yields haploid gametes. 
• Haploid (n) condition When a cell has only half the chromosome number or only one set of chromosomes.
• Diploid (2n) condition When a cell has the full chromosome number or two sets of chromosomes.
• Fertilization - Stage of development that results in a unicellular diploid zygote.
• Totipotent cell - A cell that is capable of differentiating to become any kind of cell.
• Cleavage - Stage of development involving a series of mitotic divisions to produce a multicellular blastula from a unicellular zygote.
• Gastrulation - Stage of development involving morphogenetic movements of the cells to produce a gastrula with distinct germ cell layers;
• Organogenesis - Stage of development where the different germ layers differentiate into specific organ systems.
• Ectoderm - nervous system, epidermis, sense organs
• Mesoderm - muscles, bones, and connective tissue
• Endoderm - digestive system, gametes, endocrine glands
• • Growth Stage of development characterized by an increase in size of an individual.
• Monozygotic twins

  • Also known as identical twins; result from the union of a sperm and egg to form a single zygote that splits up during the first cleavage stage. 
•  Dizygotic twins

  Also known as fraternal twins; results from the development of two or more separate fertilization events where the resulting zygotes develop almost simultaneously
• Testis

  Where sperms are produced.
• Epididymis

  Where sperms are temporarily stored.
•  Scrotal sac/scrotum

  Supports the testis and epididymis.
• Vas deferens

  • Where the sperm passes through from the testis before it joins the urethra. 
• Urethra

  Connected to the urethra and the urinary bladder;
•  Seminal vesicle

  Secretes fluid that forms part of the semen;
• Prostate gland

  Secretes fluid that also provides alkalinity to the semen;
• Bulbourethral glands

  Paired glands that produce clear, viscous secretion known as pre-ejaculate that helps to lubricate the urethra for sperm to pass through,
• Clitoris


  The homologue (equivalent) of the penis in females
• Vagina


  Main entrance to the female reproductive tract; receives the penis during sexual intercourse
• Cervix


  Where the vagina ends; projection of the uterus into the vagina; leads to the uterus
• Uterus


  Also known as the womb; where the embryo develops
• Endometrial lining/endometrium


  Innermost lining of the uterus where the embryo implants and develop
• Fallopian tubes


  Also known as oviducts; paired tubes that are connected to the uterus and terminate near the ovaries
• Ovaries


  Female gonads that release the oocytes during ovulation, which are then caught by the fimbriae of the fallopian tubes in order for the oocytes to pass on to the fallopian tubes