Module 3 Reproductive strategies in Vertebrates 2021.pptx

SSIP February 2021 LIFE SCIENCES Topic(s) : Reproduction in Vertebrates Venue: 1  SSIP AIMS/GOALS The four interconnected outcomes that drive the professional development activities for SSIP are: 1. Enhancing Teachers knowledge: deep understanding of su...

SSIP February 2021 LIFE SCIENCES Topic(s) : Reproduction in Vertebrates Venue: 1  SSIP AIMS/GOALS The four interconnected outcomes that drive the professional development activities for SSIP are: 1. Enhancing Teachers knowledge: deep understanding of subject matter knowledge and students ideas on the content 2. Enhancing quality teaching and assessment for learning: effective instructional approaches that teachers may use to ensure improved understanding by most learners. 3. Developing ICT integration skills :Use of ICT to improve teaching and learning 4. Building professional learning communities: allow teachers to start collaborating and form professional networks in non-formal settings in context of their schools 2  PROGRAMME Refer to page 17 - 20 in the PG. 3  MODULE 3 Overview of Module 3 In this module we will look at the basic concepts of ‘Reproductive strategies in animals in maximizing reproductive success in different environments’ Content You will study this module through the following units: Unit 1: Courtship behaviour Unit 2: External and internal fertilization Unit 3: Ovipary, ovovivipary and vivipary Unit 4: Amniotic egg Unit 5: Precocial and altricial development Unit 6: Parental care 4  OUTCOMES OF THIS MODULE Statement of the learning outcomes/objectives When you complete this module you will be able to: Define reproduction. – (knowledge: level A of Bloom’s taxonomy) Differentiate between the different types of reproductive strategies. – (understanding: level B of Bloom’s taxonomy) Describe different types of fertilization – (knowledge and understanding: level A and B of Bloom’s taxonomy) Understand how various types of reproduction provide advantages and disadvantages to the organisms and show evolutionary development – (knowledge, understanding and application: level A; B and C of Bloom’s taxonomy) Describe Ovipary, ovovivipary and vivipary – (knowledge, understanding and application: level A; B and C of Bloom’s taxonomy) Explain how the amniotic egg allows animals to inhabit a variety of habitats – (understanding and application: level B and C of Bloom’s taxonomy) Describe and explain different types of development – (knowledge, understanding and application: level A; B and C of Bloom’s taxonomy) Explain how parental care occurs – (knowledge, understanding and application: level A; B and C of Bloom’s taxonomy) 5  REPRODUCTIVE STRATEGIES IN ANIMALS Teaching terminology Activity 3.1 (p. 68) 7 8  Comparing sexual and asexual reproduction Sexual reproduction Asexual reproduction involves the fusion of involves reproduction of motile (male) and organisms from parts or stationary (female) the whole parent body form gametes. – no gametes involved Activity 3.2 (p. 69) Complete the table below: 10  Courtship rituals Definition : – Rituals and actions performed to attract a mate. Courtship rituals include the following actions; Displaying beauty e.g. Male peacock feathers Fighting skills, e.g. Lions, elephants Performing intricate dances, touching or vocalisation e.g. Fiddler crab Bringing food e.g. Pel’s fishing owl Performing intricate dances Displaying beauty e.g. male peacock feathers Courtship rituals Courtship rituals  EXTERNAL FERTILISATION The sperm cell fuses with the egg cell outside the body of the female. The sperm cells are discharged (released) directly into water. Examples are aquatic animals like frogs, sponges, jellyfish, worms and fish  A mass of amphibian eggs, appearing as small black spots, is contained within a gelatinous mass while they incubate in a freshwater pond. Eggs deposited in this fashion receive little or no parental protection and will soon hatch into small, wriggling tadpoles.  Advantages : Disadvantages : Chances are very slim for a sperm cell No additional energy is to meet the ova of same species. needed for parental care Predators eat the sperm and ova before or formation of a fertilization can occur Strong currents carry sperm cells away protective layer. before fertilization can occur No need for a male to Reproduction must take place in water otherwise gametes or fertilized eggs have a special organ to will dehydrate insert the sperm into the females body. Chances of fertilisation are enhanced by courtship display by fish. Does not use much energy.  INTERNAL FERTILISATION The sperm cell from the male is transferred into the female by copulation (sexual intercourse). The sperm cell then fuses with the ovum inside the body of the female. Examples : terrestrial mammals, birds, and insects. Advantages : Disadvantages : Ensures that the sperm cell Fewer eggs are comes into contact with the ovum produced. Developing embryo is protected The animal must have a from predators and removed from harsh copulatory organ to environments insert the sperm cells into the female body. Internal Fertilization Terrestrial vertebrates clasp each other tightly during copulation the male deposits his sperm into the female’s reproductive tract. For the giant Galápagos tortoises mating may take hours and is initiated by the male, who bangs his shell against that of the female to get her attention. These animals' mate in the spring.  Types of Reproduction Ovipary /Egg-laying Refers to egg laying animals Eggs are protected by a hard shell , while others are protected by a jelly like layer after fertilisation. Development does not occur inside the body The development of an organism is completed inside the egg after it has been laid Examples: frogs, insects, birds, and marine animals Advantages and disadvantages of Ovipary Advantages : Disadvantages: Eggs and sperm cells are Mortality rate is high. produced in large numbers to increase chances of survival to adulthood. Much energy is invested for parental care. Parental care ensures survival to adulthood. 22  Animals that do not lay eggs , but keep them in their bodies until they hatch. The body temperature is necessary for them to Ovovivipary hatch. There is no connection between the embryo and the mother. Examples : sharks , lizards, cockroaches and some snakes Advantages : The young one is protected from cold and predators to ensure survival The young one can develop to a fairly large size before birth Disadvantages: Fewer offspring are born More energy is used by the female carrying the eggs Snake Giving Birth Among some snake species, females bear live young This method of reproduction may be beneficial to snakes that live in cold climates, because the pregnant female can bask in the sun to keep her developing offspring warm.  Refers to animals that give Vivipary birth to live young ones. There is a connection between the developing foetus and the mother. Examples : most mammals like human beings, whales and kangaroos.  Advantages and disadvantages of vivipary Advantages : Disadvantages : The temperature is Number of off springs regulated by the mother produced is few. The mother provides More energy is used nutrition for the young one to provide parental Mortality rate is lower care. 26 27  Activity 3.3 (p.75) Study the diagram of one- 3.1 State TWO visible features in hatchling A day-old hatchlings A and B which indicate altricial development below. The diagram is not (2) drawn to scale. 3.2 The diagram represents ovipary. A B Explain ONE possible advantage of vivipary when compared to ovipary. (2) 3.3 Explain why you would expect that the yolk content of the egg of hatchling B was more than that of hatchling A. (2) 28  Activity 3.3 The diagram shows a male seahorse. A seahorse is a fish. During reproduction the female seahorse transfers her unfertilized eggs to the male’s pouch. The male seahorse then fertilizes the eggs while they are inside his pouch. The fertilized eggs stay in the pouch where they develop into young seahorses. A scientist states that a seahorse is ovoviviparous. Explain why this statement does not fit the normal definition of ovoviviparous. (5) 29  Answers Activity 3.3 3.1 The eyes are still closed The body is still naked, without a downy feather covering (2) 3.2 The embryo is directly connected to the mother as it receives nutrients through the placenta which consists of embryonic and maternal tissues.(2) 3.3 The development time is longer in hatchling B, therefore more yolk will be needed to supply nourishment to the developing embryo. (2) (6) Q1 - The female sea horse lays eggs externally, - the male fertilises the eggs externally in his pouch. - baby seahorses develop and hatch from eggs in male body. - In normal ovovivipary, internal fertilisation takes place in female body, - the fertilised eggs develop inside mother, hatch and are born alive. (5) 30 Amniotic egg 31  This is the egg laid by reptiles, birds and some mammals. The embryo develops inside the amnion and is protected by many membranes and hard shell. Amniotic fluid protects the embryo from drying out. It feeds from the yolk. The allantois removes metabolic wastes. The chorion supplies oxygen, food and water. Advantages : They are resistant to dryness Oviparous animals can move into VARIOUS environments Is protected by a number of membranes. This complicated structure can allow animals to evolve into bigger forms, and better protect themselves. Amniotic Egg A critical evolutionary development for terrestrial animals is the reptilian amniotic egg, now also characteristic of birds and some mammals. The developing embryo, protected from drying out, can survive out of water and in a variety of habitats. The yolk provides it with food, and the albumen supplies water and nutrients. Wastes are released to the allantois, an extension of the embryonic gut. Oxygen diffuses easily through the thin outer shell of the egg; TYPES OF DEVELOPMENTS PRECOCIAL DEVELOPMENT Young ones are relatively mature and are able to move around after they are born or hatch. Their eyes are open, and have good eyesight They can go out to search food for themselves. Have strong skeleton, and their body is either covered by feathers (birds) or hair(mammals). Birds need their parents to keep them warm, but this lasts for a short period. Mammals can regulate their body temperature. Examples : birds, cattle, sheep, antelopes, buffalo, elephants, hippos and giraffe.  Altricial Development Young ones are unable to move after birth and are helpless. Helpless at birth They do not have feathers Although this two-month-old (birds) and blind. Parma wallaby joey They need to be fed and successfully completed a kept warm. blind journey from its mother’s birth canal to her pouch without help, it would not survive without her.  Refers to looking after young ones through feeding, keeping them warm, protecting them from the predators. Such animals give rise to few offspring PARENTAL CARE  KEY POINTS FOR THE MODULE Here it is your choice on what you want the participants to take from the Module and what you want to summarize You may discuss around Teacher the following Learnin key points Teacher Assessin Comm for teaching and learning: inputs: gCoPA[F] s g the on Learnin activiti support learning: exam g Tasks es: and Formativ errors Possibl actions: e and e What diagnost learner the ic s ideas teacher assessm and s can ent respons give es learner s to do and 37