LU4 Sexual Reproduction (Animal) 2024 PDF

Sexual Reproduction in Animals Part 1 Mohd Ridwan Abd Rahman [email protected]  Learning Objectives 1. Differentiate between internal & external fertilisation 2. Differentiate the three types of embryos’ development Fertilisation can be internal or external Animals can be...

Sexual Reproduction in Animals Part 1 Mohd Ridwan Abd Rahman [email protected]  Learning Objectives 1. Differentiate between internal & external fertilisation 2. Differentiate the three types of embryos’ development Fertilisation can be internal or external Animals can be grouped into three categories based on the embryonic development; oviparity, viviparity & ovoviviparity  EXTERNAL INTERNAL Sperms are deposited in or near Sperm cell unites with the egg reproductive tract & the union cell outside the female’s body takes place within the female’s body  EXTERNAL INTERNAL Environmental cues Requires complementary (temperature) & body mating behavior & chemicals (pheromones) reproductive organs between ensure sperms & eggs released the two sexes at the same time & in close proximity  EXTERNAL INTERNAL High number of gametes Low number of gametes Frog Mammals Fish  EXTERNAL INTERNAL Massive zygotes Fewer zygotes  EXTERNAL INTERNAL Lack/No parental care Parental care A female salamander coiled around her Where is mommy nest to protect the egg from predators & daddy? Exception: Egg A female frog that swallows its eggs or carrying on the back to protect them. The embryos of animals undergo either one of these three types of development; OVIPARITY Laying eggs External & internal fertilization Yolk in the egg provides nutrients that will sustain the development of the embryo E.g., frogs, snakes, lizards, bird, fishes etc https://i.ytimg.com/vi/ihaR-_SDemE/maxresdefault.jpg https://brucefinocchio.files.wordpress.com/2012/05/young-female-yellow-rumped-warbler-minutes-after-laying-her-first-egg_ba45520d7c.jpg  VIVIPARITY Development of the embryos in female’s body Live birth Internal fertilization The embryo obtains its nutrients & oxygen from the female via placenta E.g. Mostly in mammals, rare in fish, reptiles & amphibians  OVOVIVIPARITY Embryos develop inside eggs that are retained within the mother’s body until it ready to hatch Live birth Internal fertilization No nutrition is provided to the developing embryo except for egg’s yolk http://www.bio.gc.ca/sharks/images/reproduction-fig14.jpg E.g. Snake, stringray, seahorse, frog & etc 1. CNIDARIA E.g. Hydra Reproduction involves both sexual & asexual (budding) Some species of Hydra are hermaphrodite  Testis Ovary Budding Asexual Sexual The interstitial cells of the ectoderm divide repeatedly & form swellings in the body wall, to become testis & ovary Many motile sperms are formed in the testis, yet ovary usually contains one ovum https://www.google.com.my/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwjZy6ft_IPkAhXEQY8KHSyLATAQjRx6BAgBEAQ&url=htt ps%3A%2F%2Fcommons.wikimedia.org%2Fwiki%2FFile%3AHydra_reproduction.png&psig=AOvVaw1aYk-_YcaxFeBf0lNrdz9a&ust=1565927494378638 Ovum remains in the ovary & is fertilised by sperm released from a mature testis In favourable conditions, the embryo is released & develops into a mature Hydra  2. ANNELIDA Annelids have true coelom Reproduction is normally sexual & the worms are hermaphroditic E.g. Pheretima (earthworms) Male pore Clitellum Female pore Spermathecal opening http://2.bp.blogspot.com/_FLSPZURcXIQ/TI2joXZdClI/AAAAAAAAAOQ/Pdv-bCErX4g/w1200-h630-p-k-no-nu/earthwormdiagram.jpg https://upload.wikimedia.org/wikipedia/commons/f/f6/Mating_earthworms.jpg During copulation, two worms align their bodies in opposite directions, and exchange sperm The worms reproduce by exchanging & storing the sperm from another individual via spermatheca After the copulation, the worms will separate from each other The clitellum secretes a mucous cocoon that slides off along the worm, collecting eggs from the oviduct & sperms from the spermatheca Spermathecal opening Eggs + sperm Female pore Fertilisation takes place in the cocoon & the cocoon slides over the head of the worm, drops into the soil, closes off & a few eggs hatch two weeks later http://eng.green-pik.ru/image/content/15 http://earthwormresources.weebly.com/uploads/1/7/1/2/17120986/259902600.jpg  3. ARTHROPODA E.g. Periplaneta Most insects reproduce sexually Reproductive adaptations include internal https://c1.staticflickr.com/3/2756/4282167421_ee9a4c0246_b.jpg fertilisation & oviparity (in some cases viviparity)  Male Testis Male insect has a pair of testes which produce sperm The sperm is carried by Seminal vas deferens, to the vesicle seminal vesicles Ejaculatory duct Vas Seminal vesicles unite to deferens form a common ejaculatory duct which Clasper Pseudo-penis leads to a penis https://biologyaipmt.files.wordpress.com/2016/05/119.jpg?w=840  Female Female insect has a pair of Ovaries ovaries, which contains ova The ova enter oviducts & then the vagina Spermatheca, which is Oviduct connected to the vagina, Vagina stores the sperm ejaculated from the male during mating Spermatheca Oothecal chamber https://biologyaipmt.files.wordpress.com/2016/05/119.jpg?w=840 When female is ready to mate, it produces a chemical cues/pheromone that attracts males The male then will flap their wings & probe the females with their abdomens when they sense the pheromone http://farm1.staticflickr.com/101/314640996_abeb572add_z.jpg?zz=1  During mating, the tips of the abdomens are held close together, then a package of sperm is inserted into the vagina of the female After mating, ova are passed down to the vagina & fertilised by the sperm in the spermatheca http://farm3.staticflickr.com/2771/4334504087_84576b0a22_z.jpg?zz=1 https://c2.staticflickr.com/8/7473/15659101558_c59ec339fa_c.jpg The fertilised egg are carried in a sac called the ootheca which protrudes from the posterior end of the female cockroach After about six weeks, young nymphs emerge  4. OSTEICHTHYES E.g. Seahorse (Family: Syngnathidae) Seahorses are an example of ovoviviparous animal Male seahorse incubates the fertilised eggs https://seahorseproject.files.wordpress.com/2011/12/pregnant-seahorses.jpg The female seahorse deposits eggs into a pouch on the male's abdomen The male releases sperm into the pouch, fertilising the eggs The embryos develop within the male's pouch, nourished by their individual yolk sacs https://s-media-cache-ak0.pinimg.com/originals/29/f1/bf/29f1bf3b3ead3a8a16dfd08ed08d85e8.jpg After the embryos have developed, the male gives birth to tiny seahorses  5. AMPHIBIA E.g. Anurans (frogs, toads) Frogs have separate sexes and fertilisation is external https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiu95z004zdAhXLs48KHVz4AScQjRx6BAgBEAU&url=https%3A%2F%2Fwww.pinterest.com%2Fpin%2F565905509400964083%2F&psig=AOvVaw3SXx-yVaToDZpZziayGGta&ust=1535439359420802 Functions of the urogenital organs of frogs MALE FEMALE Uterus: female genital organ that Testicle: male sex organ which holds the fertilised egg during its produces spermatozoa development Spermatic canal: tube that Oviduct: passage through which carries sperms the egg leaves the body of the frog Ureter: tube that carries urine Ovary: reproductive gland that from the kidneys to the bladder produces ova Cloaca: orifice shared by the Cloaca: orifice shared by the urinary, genital and intestinal urinary, genital and intestinal tracts of a frog tracts of a frog. During breeding season, the reproductive behaviour of both sexes is temporally and spatially synchronised; same time and same place Male frogs attract receptive female frogs by their mating calls Mating call The male frog then mounts the female and grasps her on the side This mating position is known as amplexus The male anurans do not have penis During amplexus the female discharges eggs into water while the male sheds sperms over the eggs The sperm/egg of the male/female frog exits the body via cloaca The act of releasing sperm and eggs into the environment is referred to as spawning. https://c2.staticflickr.com/6/5053/5497556343_6c169934df_b.jpg In some species, some form of parental care is shown such as incubating the eggs on their back, in the mouth or stomach The Male Night Frog (Nyctibatrachus sp.) guarding its clutch of eggs Nyctibatrachus sp. https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwj7yK73mfvcAhWIto8KHYCPAD0QjRx6BAgBEAU&url=https%3A%2F%2Fwww.jungledragon.com%2Fimage%2F34156%2Ffathers_affection.html&psig=AOvVaw1HIiMhMIL9uXDG5gnBqnfa&ust=15348 39773326572 Males are also observed transporting their tadpoles on their back Ranitomeya imitator https://c1.staticflickr.com/9/8094/8502048601_fc9dbcb3e8_c.jpg  6. REPTILIA E.g Order: Squamata (snake and lizards) Exhibit internal fertilisation Courtship behaviour and production of an amniotic egg are observed Mostly are oviparous or viviparous http://fivetooltool.blogspot.com/2010/12/top-10-nfl-week-14-ad-questions.html Requires intromittent organ (penis), which is used to inject sperm into the female’s reproductive tract https://c1.staticflickr.com/7/6115/6258053212_6c97763d16_z.jpg The presence of paired copulatory organs (hemipenes) in the male is characteristic of the Order Squamata (snakes, lizards) http://www.californiaherps.com/lizards/images/ecpalmeripl506hp2.jpg The male will insert one of its pair of hemipenes into the female cloaca during copulation Sperms will retain in female body for years http://caspost.com/5-weirdest-animal-sex-facts/  Mating ball of a red sided garter snake When a female garter snake emerges from hibernation, she releases a pheromone that attracts hundreds of male snakes in the vicinity to rush her and create a large squirming "mating ball.” The male garter snake has two penises, called "hemipenes," on each side of its body. The male will try to use the best-positioned penis to mate with the female at the center of the mating ball.  7. AVES Exhibit internal fertilization 90% of bird species are monogamous Courtship rituals The ultimate purpose of courtship is to attract a receptive mate There are several different courtship rituals, but most species will use only one method overwhelmingly Singing is one of the most common ways birds attract mates Flamboyant plumage colors can show off how strong and healthy a bird is Superb bird of paradise Physical movements (dancing) including wing flaps, head dips and bill rubbing are part of a courtship ritual https://media1.giphy.com/media/57ZhsMNHHvu80/giphy.gif Northern Cardinal Male offers their female partner food as gift of affection https://www.wbu.com/wp-content/uploads/2016/07/540x340-courting-mating-450x283.jpg Cloacal kiss Copulation involves a 'cloacal kiss', with the male on the female's back & twisting his tail under the female's  8. MAMMALIA Exhibit internal fertilization Monotremes are mammals that lay eggs (oviparous) and have no teats. The milk is provided for their young by being secreted by many pores on the female's belly E.g. Platypus, Echidna Marsupials are viviparous mammals that carry their young in a pouch early on during their development. Marsupials give birth to immature young that continue to grow in the mother’s pouch E.g. Kangaroo, Wallaby, Koala Monotremes and marsupials are non-placental mammals Eutherians are placental mammals (viviparous), which their embryo obtains its nutrients from the mother by placenta Exhibit parental care 90% of mammal species are placental mammals E.g. Cats, dogs, elephants, rodents, horses, primates, whales & etc Thank you