True or False? “Survival of the Fittest” means that the strongest, fastest, smartest organisms will survive and reproduce.

Consider the following…..

The Opossum A Survivor

The Survivor Opossums are one of the oldest mammal species on Earth. Fossil records show the opossum species has lived on Earth for more than 100 million years. Opossums walked (well, waddled) with dinosaurs.

The Virginia Opossum

"Opossum" is derived from the Algonquin Indian word apasum, meaning "white animal." A creature without specialized body structure or food preference, the opossum thrives in many settings. It is found throughout Massachusetts, where it is classified as a furbearer. The Virginia Opossum The Virginia Opossum Didelphis virginiana

Marsupials The opossum is a marsupial (like kangaroos). Marsupials are born before they are fully developed, and continue their growth and development in a pouch on their mother's abdomen. Virginia OpossumThere is only 1 species of marsupial in North America: the Virginia Opossum. Most marsupials were confined by continental drift to the “island continents” of Australia & South America. over 200 AustraliaThere are over 200 species of marsupials in Australia, including the kangaroo, koala, Tasmanian devil and the wombat.

2 months 4 to 6 weeks The female opossum has a pouch like that of a kangaroo. After the baby opossums are born, they spend about 2 months in the mother’s pouch feeding on her milk. Then they move out of the pouch to their mother's back where they spend 4 to 6 weeks.

The opossum’s wide distribution shows that it is very successful in (well-suited to) a wide range of environments. What are 2 types of environments that do not have opossum populations? Distribution of the Opossum in North America

Reasons Why the Opossum Should Be Extinct So how has the opossum species survived for more than 100 million years? It is slow-- top speed of 1.7 mph It is slow-- top speed of 1.7 mph It is small ( 6 to 12 pounds) It is small ( 6 to 12 pounds) It is not smart (one of the smallest brain- to-body ratios of any land mammal). It is not smart (one of the smallest brain- to-body ratios of any land mammal). It has tiny teeth & claws--. It has tiny teeth & claws-- (not equipped for fighting or self-defense).

Is it because we ’ re so cute? Nope.

How has the opossum survived ? 1. They'll eat anything (they’re scavengers). food generalists. 1. They'll eat anything (they’re scavengers). They are not food specialists, they are food generalists. 2. They’re unusually disease-resistant. 3. They are very resistant to snake venom - a dose of rattlesnake venom that will kill a horse barely affects an opossum.

4. They have a prehensile tail (able to grasp or hold objects), which they use for balance and to carry materials. Opossum carrying nesting material Baby opossums hangin’ out

5. They have an opposable thumb on their hind feet, which makes them good climbers.

6. They are nocturnal (active at night), and are experts at hiding during the day.

7. And…. when threatened by predators, they play dead. No, it’s not really dead. Looks like it, though, doesn’t it?

Playing Dead When an opossum is threatened it When an opossum is threatened it hisses and growls, emits a foul order, vomits, or defecates to repel the enemy. If these tactics don’t work, the opossum passes out. It’s not an act! It’s an involuntary reaction to overwhelming danger. The opossum goes into a shock-like state; the heart rate drops, body temperature decreases, the tongue hangs out, it drools, it appears dead. Most predators won’t eat dead animals. They’ll sniff around, then leave it alone. If these tactics don’t work, the opossum passes out. It’s not an act! It’s an involuntary reaction to overwhelming danger. The opossum goes into a shock-like state; the heart rate drops, body temperature decreases, the tongue hangs out, it drools, it appears dead. Most predators won’t eat dead animals. They’ll sniff around, then leave it alone. After a while (from a minute up to 6 hours) the opossum wakes up & waddles away. After a while (from a minute up to 6 hours) the opossum wakes up & waddles away.

Survival of the Fittest Opossum!!! So, the next time someone says, “Survival of the Fittest means the strongest, smartest, fastest organism survives,” remember the Opossum!!! T.Rex (strong)velociraptors (fast, smart)extinct T.Rex (strong) and velociraptors (fast, smart) are extinct, but the opossum lives on! Survival of the Fittest means the organism that is best suited (is the best match) to its environment will survive and reproduce.

Short-tailed opossum from Brazil Brushtail opossum, Tasmania Murine Mouse Opossum, South America Australian honey opossum Other Opossum species… Sugar glider, Australia

Talking Opossums (not really) Baby opossum swimmingOpossum playing deadopossum