Males & Females Flashcards
Q: What is sexual dimorphism?
A: Sexual dimorphism refers to the distinct physical differences between males and females of the same species.
Q: Which of the following is an example of sexual dimorphism? A) Older male buffalo are bigger than younger males B) Male caribou have antlers C) Male umbrella birds have elaborate feathers
A: C) Male umbrella birds have elaborate feathers. This is a correct example of sexual dimorphism, where males use elaborate feathers to attract females.
Q: Why is the difference in size between older and younger buffalo not an example of sexual dimorphism?
A: The size difference between older and younger buffalo is due to age, not sex, so it doesn’t qualify as sexual dimorphism.
Q: In caribou, do both males and females have antlers?
A: Yes, both male and female caribou can have antlers, which means this is not an example of sexual dimorphism.
Q: How do peacocks exhibit sexual dimorphism?
A: Male peacocks have elaborate feathers and bright colors, whereas females are more subdued in appearance.
Q: What is the main challenge in identifying sexual dimorphism in dinosaurs?
A: Sexual dimorphism in dinosaurs is hard to confirm because many species are known from single specimens, making it difficult to compare males and females.
Q: What evidence from Confuciusornis suggests sexual dimorphism?
A: Confuciusornis males are thought to have longer tail feathers, while females lack these feathers, suggesting sexual dimorphism similar to modern birds.
Q: How did female dinosaurs get the calcium needed to form eggshells?
A: Female dinosaurs stored calcium in their bones, particularly in a type of bone called medullary bone, to use during egg-laying.
Q: What is medullary bone, and why is it important?
A: Medullary bone is a special bone that stores calcium in female dinosaurs before laying eggs. It allows them to form strong eggshells without weakening their own bones.
Q: How can medullary bone help paleontologists identify female dinosaurs?
A: Medullary bone is only found in females preparing to lay eggs, so its presence in fossils helps identify female dinosaurs.
Q: What role did osteoderms play in female Rapetosaurus?
A: In female Rapetosaurus, thin, hollow osteoderms likely stored minerals like calcium, which would have been used for egg production.
Q: How do paleontologists know that certain dinosaur fossils belong to females?
A: Some female dinosaur fossils have been found with eggs inside them, ready to be laid, providing clear evidence that they were female.
Q: What type of fertilization did dinosaurs use, and what evidence supports this?
A: Dinosaurs used internal fertilization, as evidenced by their hard-shelled eggs, which had to be fertilized inside the body.
Q: What comparisons can paleontologists use to infer how dinosaurs mated?
A: Paleontologists compare dinosaurs to modern animals like crocodiles and birds to infer how they might have mated, as these animals share similar reproductive behaviors.
