Question

1. Analogous structures perform similar functions but do not arise from common ancestry. What explains the existence of analogous structures? Name 3 differences between the skull features of chimpanzees and humans. What era of geologic time are we in currently?
2. Name two types of organisms that belong to each of the phyla: Annelida, Mollusca, and Echinodermata. Name an adaptation of a crayfish and one adaptation of a grasshopper that benefit their survival in their respective environments. Describe the types of skeletons that arthropods and vertebrates have。

Answer 1

Answer:

• The presence of analogous structures (which serves similar functions) but do not arise from common ancestry can be explained by the theory of convergent evolution.
  It says that different species at different times have developed similar features independently of one another which serves the same purpose.
  It can be explained more in such a way that these similar features have formed in different species due to the same selection pressure that existed in the environment and those species had to cope up with that and formed favorable features at a different evolutionary time period, independently of one another. So, certainly, they had no ancestry.
  One example of an analogous structure is the wings of insects, bats, and birds.
  Insects were probably the first creature that developed wings for the flight. Then after millions of years, birds developed a similar feature i.e.feathery wings which were formed to serve the purpose of flying. Yet many years later bats used the membranes between their finger bones to have a flight and that is called wings of bats. They all were formed for the same purpose- to fly but at different times and with ancestry.
  
  
• Three difference between the skull features of chimpanzees and humans are as follows-
  
  The human skull has a larger braincase compared to a chimpanzee's skull.
  The front of the human skull is more or less flat whereas the chimpanzee skull protrudes in front.
  The human skulls have prominent chin and forehead whereas the chimpanzee doesn't have a forehead or chin.
  
  
• We currently live in the Cenozoic era of geologic time.
  
  
• One organism belongs to the Annelida phyla is Pheretima posthuma one in Mollusca is Pila globosa and one in Echinodermata is Asterias rubens.
  
  
• The crayfish have eyes with short stems which allow them to turn the stem and see in various direction.
  The grasshoppers have very sharp hearing abilities that protect them from predators. They can hear the predators coming.
  
  
• The arthropods have skeletons made up of chitin on their outer surfaces that is why it is called exoskeletons. The exoskeleton of arthropods is articulated which meets at the joints. The exoskeletons of arthropods cover the external structures as well as some internal structures. A type of exoskeleton present in arthropods is shell structure found(found in crustaceans) outside their body.
  
  The vertebrates skeleton is present inside the body covered by muscle and skin. So the type of skeleton in vertebrates is endoskeleton. Which is bony and cartilaginous. The vertebrate skeletons are also articulated. there are some exoskeletal appearances found in vertebrates too such as nails, hair, hoofs, feathers, beak, etc.