Question

Why were there no large mammals around when the dinosaurs occupied the land?What features do primates have to allow for an arboreal existence?

What do you believe is the single most important feature that mammals possess that have allowed for their success and why?

Answer 1

Question) Why were there no large mammals around when the dinosaurs occupied the land?

Answer) It can be attributed to mainly two reasons,

1. Mammals are endotherms: Mammals, unlike dinosaurs, maintain their body temperature. Example: Humans maintain body temperature of 37 degrees at all the time. This comes at a cost, maintaining constant internal body temparature consumes a lot of energy. When more than half of energy is going to maintaining the body temperature animal cannot risk by increasing more body mass. Whereas in the case of dinosaurs they are ectotherms, meaning their body temperature depends on the external temperature. This feature gave them the extra energy that the body can use, hence they expanded.

2. Maintaining a low profile: Mammals 165 million years ago were sure like, very tiny. This might be simply to hide out of predators at that time. This might have given them a surviving advantage at that time.

Question What features do primates have to allow for an arboreal existence?

Answer) Following features evolved in primates that supported arboreal or tree-dwelling existence.

1. Rotating shoulder joints - This has given them flexibility of freehand rotations, which helps them in climbing trees easily.

2. Big toes - Evolution of big toea and separation of toeas and thumbs helped them in gripping strongly.

3. stereoscopic vision or tow overlapping fields from two eyes- This allowed to have depth and gauging vision.

Question What do you believe is the single most important feature that mammals possess that have allowed for their success and why?

Answer)) I belive adaptation or the rate at which mammals adopt is the single important feature that helped mammals in their success.

Mammals post dinosaur age went on to adapt various environmental conditions

example: we can see

Flying mammals - bats

Swimming mammals - dolphins and whales

Arboreal mammals - monkeys

Burrowing mammals- rabbit etc

This adaptive radiation into various new niches has helped them to become successful colonising organisms on earth.