MARSUPIALS-EVOLUTION, DEVELOPMENT AND

REPRODUCTION

By: Samantha Seery

Mentor: Dr. Paulson (Zoology, Entomology and Biology)

Reproduction Approaches

There are two main types of mammals; placental and marsupials. The main differences between these tow groups is the evolutionary diversity in their reproductive approaches. Placental mammals give birth to young that develops inside the mothers womb, and have mobility within hours after birth. Whereas, marsupials give birth to young that are born les developed then go into the mother’s pouch to continue developing, where they stay until they are able to move on their own.

Evolution

When the continents drifted apart, they separated a large group of marsupials in two. These groups are now Australian marsupials and South American marsupials. Although these two groups evolved miles apart from each other, they performed what is known as parallel evolution, or convergent evolution. This means that they two groups evolved very similarly. The reason that these groups evolved parallel to each other is because they come from the same lineages, or line of descendants.

Kalihi Rock Wallabies

There has been a discovery of a new species known as the Kalihi Rock Wallaby on the island of Oahu, Hawaii. This species is an example of what people call rapid evolution. Rapid evolution is when something evolves rapidly. These wallabies are all descendants of a single pair of wallabies that escaped from a Hawaiian zoo in 1916. Now, the numbers of rock wallabies in Hawaii has grown exponentially. This species is a prime example of rapid evolution because in a short amount of time, they have evolved enough to survive outside of an enclosure.

Endangerment and Extinction

Australia is acknowledged as the worst country and continent in mammal conservation. This is figured because out of a total of 245 mammal species, 59 of them have been listed extinct in Australia as of 1994. 60% of the 59 extinct species were marsupials. There are six main hypothesis about why these species have become extinct or endangered; 1) habitat destruction , 2) habitat change and degradation, 2) introduced animals, 3) disease, 4) climate changes, and 6) a combination of all of the above factors.

http://theconversation.com/australias-critically-endangered-animal-species-11169

Graph

This graph represents marsupials that are either near threatened, threatened, or extinct. It shows that in 2012, 58%of marsupials were at low risk of extinction, 10% were near threatened, 21% were threatened, 3% were extinct, and 8% were data deficient. The amount of near threatened to threatened marsupials, proves that we have not been protecting marsupials or their habitats well enough.

Conclusion

In conclusion to the research I have done and the information I have collected, I now know a lot more about marsupials, their evolution, their state of endangerment, and their differences to placental mammals. I have been able to conclude, that marsupials have been around for a very long time, evolving throughout time. They have been able to evolve parallel to each other for many, many years. Marsupials have evolved to survive in unlike habitats long enough to still be living today. However, I can see that if humans do not change things marsupials will be on the way to total extinction.

Sources and Recognition

Scripture on creation.org The conversation.com Cstl-cla.semo.edu ( Some

Endangered Australian Marsupials)

Pbs.org Nhc.ed.ac.uk (Origin and

Evolution of Marsupials) My amazing scientists in the

classroom mentor, Dr. Paulson

Thank you!