Reproductive System:

Transcription

1 Reproductive System: Purpose: The reproductive system combines genetic information from both parents (in most animals) to produce new life forms. This system produces sex cells (gametes), delivers them, and protects a developing fetus until birth.

2 Comparing Reproductive Systems Asexual Involves one parent. As a result, the offspring tend to have the same genotype and phenotype as the parent. Sexual involves the fusion of two gametes. Sperm and eggs are sometimes produced by the same individual and sometimes produced by different individuals. Ex: Flatworms can divide into 2 halves; each half grows into a separate organism. Cnidarians undergo budding where a new individual grows from and then breaks off of the parent individual. Ex: Vertebrates

3 Comparing Reproductive Systems Asexual Sexual Results In: Genetically identical offspring Results In: Genetic variation

4 Comparative Reproductive Systems In most animals, individuals are either definite males or females; however some species are hermaphrodites. This is when one organism produces both egg and sperm. Ex: earthworms and garden snails

5 There are 2 major mechanisms of fertilization external fertilization: q Used by many aquatic invertebrates. q Eggs and sperm are simultaneously shed into the water q The sperm swim through the water to fertilize the egg

6 There are 2 major mechanisms of fertilization internal fertilization: q eggs are fertilized within the reproductive tract of the female, q Then covered with egg shells and/or remain within the body of the female during their development

7 Parts of the Reproductive System **Gametes: Specialized sex cells ~sperm and egg

8 Female Parts of the Reproductive System 1. ovaries- produce female gametes (ova or egg) 2. Fallopian tubestransport egg to uterus (= oviduct) 3. uterus - organ where fertilized egg develops 4. vagina - birth canal

9 Female Parts of the Reproductive System 5. placenta - serves for gas exchange and metabolic products with mother 6. umbilical cordattaches embryo to placenta 7. Amniotic fluid - keeps the embryo moist and protected

10 Female Reproductive Cycle Regulated by hormones produced by the endocrine system, such as estrogen and progesterone. This cycle begins at puberty and continues until menopause (age 45-55) Repeats about every 28 days

11 Day 5-14: uterine lining thickens, preparing to receive a fertilized egg Day 14: ovulation if the releasing of a mature egg into the fallopian tube occurs around the 14 th day of the cycle. Female Reproductive Cycle

12 Day 14-28: The first 3-4 days of this stage, the chance of fertilization is highest. Day 1-5: menstruation is the discharge of the uterine lining, blood, and unfertilized egg and occurs between days 1-5 of the cycle. q if fertilization does not occur within 2-3 days, the unfertilized egg passes through the uterus without implanting q uterine lining detaches from the wall and is discharged, along with blood and the unfertilized egg through the vagina Female Reproductive Cycle

13 Female Reproductive Cycle

14 Male Parts of the Reproductive System 1. tes's- produces male gametes (sperm) 2. urethra- carries sperm to penis 3. penis - external sex organ, delivers sperm to female 4. Scrotum- protects testes and helps maintain sperm temperature 5. Prostate- produces semen

15 The Reproductive system working with other body systems Nervous System: Reproductive hormones affect brain development and sexual behavior. The brain controls mating behavior Endocrine System: Endocrine Glands produce sex hormones (ovary and testis)

16 Fun Facts Seahorse reproduc'on is unusual because the male is the one that becomes pregnant. Seahorses are monogamous and will only mate with one partner. Clownfish can change gender. If the female dies, the male will change sex and become the female. The only mammals to lay eggs are the platypus and the echidna. The mothers nurse their babies through pores in their skin. A baby platypus remains blind ajer birth for 11 weeks. A baby octopus is about the size of a flea when it is born. Gesta'on periods (period of 'me between fer'liza'on and birth) vary from one animal to the next Animal Elephant Horse Human Pig Rat Average Gesta'on Period 624 days (~2 years) 336 days (~11 months) 266 days (~9 months) 115 days (~4 months) 21 days (less than a month)