Evolution is not about arriving at some destination. Animals don’t evolve until they become humans or tyrannosauri and then declare they’ve won the game.
Evolution is an ongoing process of change. Animals change in random ways. If the changes are bad, the animals die and the changes disappear. If the changes are good, the animals live and breed and the changes spread through the species.
why would they be hundreds of feet tall to feed on plants that were 10 feet tall?
No it wasn’t. No dinosaur was as small as many modern mammals. Even if you include birds as dinosaurs, the average size of non-avian dinosaurs was far larger than most modern birds.
thank you for the replies and sharing information i wasnt aware of. i will do more reading to become beter educated on the specific eras thank you all
I thought we were in the early stages or midst of one right now?
Extinction rates now are much higher than they have been in the recent past, mainly due to direct or direct human impacts, but aren’t close (yet) to the levels seen in the major mass extinction events in the past. Whether or not we reach them eventually may depend on how severe climate change and other effects become over the next couple of centuries.
I was distinguishing between the anthropogenic species extinction and those resulting from natural cataclysms. By paelontoligical standards, the current rates of extinction are currently less than what is estimated for historical biotic crises, but the rate of increase of extinctions gives a trend that may be on par with events like the K-T or Triassic-Jurassic extinction event. And it should be noted that we are still actively classifying new species, so actual rates of extinction may be higher than observed.
Stranger
No dinosaur was “hundreds of feet tall.” Sauroposeiden, possibly the tallest, may have reached 56 feet. Many trees probably reached hundreds of feet tall in the Mesozoic, and it is speculated that tall sauropods used their long necks to browse on these trees. However, other sauropods probably browsed on low growth. Their necks in general were an adaptation for gathering food over a wide area with minimal effort, rather than for browsing tall trees.
Are you being entirely serious?
No dinosaurs were “hundreds” of feet tall. The longest sauropods could probably have reasonably reached up somewhere under 100 feet, which is not a problem for most forests, including the forests that existed back then.
ETA: along the same lines, why aren’t more current animals hundreds of feet tall to feet on trees? Why are elephants so large when they don’t need to feed on tall trees to survive. The size of the animal is not tightly correlated with the size of its food source. That’s true now, and based on everything we’ve discovered so far, it was true in the age of dinosaurs as well.
The Baluchitherium aka Paraceratherium, aka Indricotherium weighed in at up to around 16 tons and 16’ tall. This comes in there with about the average dinos lumped as Brontosaurus . (I hate the term Apatosaurus, they can suck it 
)
Trust me, if you saw one of them lumbering towards you, you’d think it was a huge as a dino.
The long-necked sauropods–that is, brontosaur type creatures–were only one type of dinosaur. And we think that only some of them used their long necks to feed on trees. Some of them used their long necks to stand still and eat acres of ground cover while only moving their heads.
And have you ever been to a museum to see dinosaur skeletons? They were really big, but not hundreds of feet.
We used to have the idea that the big sauropods were aquatic or semiaquatic like hippos, but now we know that they lived on dry land and ate land plants.
As for the notion of yearly global floods, think about it. How does a polar ice cap form? When snow falls in the winter, and doesn’t melt in the summer. If the snow melts in the summer you don’t have an ice cap, you have winter snow. So even if there’s a lot of snow in one winter, you’re not going to have enough snow to lower global sea levels, and cause floods when that winter’s snow melts.
And besides, the current evidence is that the world was generally much warmer in the age of Dinosaurs than it is today. That means that there were no polar ice caps–even at the north and south poles you’d have bare ground (or sea) in the summer. Dinosaurs lived in Antarctica, which was forested at the time. Sea levels were higher because of the absence of polar ice caps, what is now the American great plains was a shallow inland sea during the Cretaceous.
IANA paleontologist, but couldn’t one reasonably argue that evolving into birds, as it were, was the long-term survival tactic of those small dinosaurs that survived the great extinction? Though early mammals were generally small as well, and primitive in comparison to their descendants, they must have been far better equipped to compete and reproduce. Developing feathers and taking to the treetops and the air was a good solution if the small-animal ground-dwelling niches were being taken over by mammals.
Of course, I do realize that birds and mammals didn’t just appear at the end of the Mesozoic, so I’m not suggesting there was a simple changeover to mammals and birds at that point.
Umm, no. Altho there is still some dissent on whether or not birds came directly from dinos (some think they just had a common ancestor), they split off around the late Jurassic, 160 some odd millions of years ago or about 100 million years before the KT event. The first “true birds” (and of course this is the subject of some disagreement) occurred about 120 mya. The KT event occurred about 66 mya.
Side question: I hear comments like the one above quite often, but I never hear people say that alligators or crocodiles, et al, are dinosaurs. Are they not considered dinosaurs? Or is it just so obvious that nobody (that I recall reading, anyway) mentions it?
ETA: I did read this part below, but I wanted to ask anyway:
“The only things that lived were things that were small and could burrow under debris and things that could live a long time without food (like crocodiles).”
Dinosaurs were closer to birds than reptiles.
They were an advanced branch that split off from early crocodiles, then developed warm-blooded metabolisms.
Define “dinosaur”. If you mean anything big and scaly and extinct, then crocodiles aren’t dinosaurs because they aren’t extinct.
If you mean any organism that evolved from the last common ancestor of a sparrow and a triceratops (a common cladistic definition), then crocodiles aren’t dinosaurs because their ancestors had split off before that creature existed.
The classic definition to qualify as a dinosaur you have to belong to the order Ornithischia or Saurischia, which are thought to be sister groups. And crocodiles are not part of either group.
Check out this tree that outlines the current consensus view:
OK. Thanks for the answers.
But there is more ignorance to be fought…
The way I’m reading this chart it’s saying that birds evolved from theropods, who evolved from “(lizard-hipped dinosaurs)”; and not that they evolved from bird-hipped dinosaurs. Am I not reading this right?
You are reading that correctly. Birds evolved from “lizard-hipped dinosaurs”. I suspect that the two branches of dinosaurs were named before it was known for sure that birds had evolved from dinosaurs, and the resemblance of the hips of “bird-hipped dinosaurs” to the hips of actual birds was coincidental or a case of convergent evolution.
Years ago I was looking through a book my nephew had on dinosaurs and it said that there were 2 types of dinosaurs: Those with a wish-bone, and those without. (I would not have been allowed to read a book that referenced evolution when I was a child.) I assumed that birds evolved from those with a wishbone, and when I saw that chart I assumed that the “-hipped” part referred to the wish-bone. (I really don’t know what the wishbone is.)
Could someone clarify the wishbone thing?
Wishbones are fused clavicles (collar bones).