Each individual chromosome *may line up either way/flipped on the equator of the spindle *This means that gametes will have differing number/mix of maternal and paternal chromosomes/chromatids (at least 1 of the *compulsory and any 4 which could include compulsory points) Formation of an ovum - During oogenesis - diploid - in the ovary - undergo meiosis - to form a primary oocyte - consisting of haploid - One cell develops into an ovum Relevance Logical sequence Comprehensive All information provided is relevant Ideas arranged in a logical/ Answered all aspects to the question cause-effect sequence required by the essay in sufficient detail At the following marks All the information regarding All the information provided is should be obtained: crossing over, random relevant to crossing over, random Crossing over (5/7) arrangement and development arrangement and development of Random arrangement of an ovum is arranged in a an ovum. logical manner. (3/5) There is no irrelevant information Development of an ovum (3/5) 1 mark 1 mark 1 mark Reproduction in vertebrates Question 1 - The female sea lays eggs externally, - the male fertilises the eggs externally in his pouch. - baby seahorses develop and from eggs in male body. - In normal ovovivipary, internal fertilisation place in female body, - the fertilised eggs develop inside mother, hatch and are born alive. (5) Question 2 C (2) Question 3 3.1 The eyes are closed The body is still naked, without a downy feather covering (2)
Each individual chromosome *may line up either way/flipped on the equator of the spindle *This means that gametes will have differing number/mix of maternal and paternal chromosomes/chromatids (at least 1 of the *compulsory and any 4 which could include compulsory points) Formation of an ovum - During oogenesis - diploid - in the ovary - undergo meiosis - to form a primary oocyte - consisting of haploid - One cell develops into an ovum Relevance Logical sequence Comprehensive All information provided is relevant to the question Ideas arranged in a logical/ cause-effect sequence Answered all aspects required by the essay in sufficient detail All the information provided is relevant to crossing over, random arrangement and development of an ovum. There is no irrelevant information All the information regarding crossing over, random arrangement and development of an ovum is arranged in a logical manner. At the following marks should be obtained: Crossing over (5/7) Random arrangement (3/5) Development of an ovum (3/5) 1 mark 1 mark 1 mark Reproduction in vertebrates Question 1 - The female sea lays eggs externally, - the male fertilises the eggs externally in his pouch. - baby seahorses develop and from eggs in male body. - In normal ovovivipary, internal fertilisation place in female body, - the fertilised eggs develop inside mother, hatch and are born alive. (5) Question 2 C (2) Question 3 3.1 The eyes are closed The body is still naked, without a downy feather covering (2)