When Tarzan's ape father is shot, he lands face down. In the next shot, he is face up, then face down again, then rolled him over onto his back.
When Tarzan's "ape father" is shot, Tarzan is seen from the left. His hair is messed up on both sides. When Tarzan is seen from the right, the hair on the right side of his head is perfectly combed. Then when seen from the front again, when carrying his "father," his hair is messed up on both sides.
When Sir Evelyn finds out that Major Jack is shooting apes, he storms off to find him, roughly shoving an African guide standing to his right out of the way. In the next shot, the guide is gone.
When the Ape in the tree is shot in the chest, the bullet wound almost touches its left nipple, and sprays blood across a large area of the chest. The ape then falls, lands face down, and is turned over, Tarzan picks the dead animal up and carries it. The wound on the ape has moved several inches lower and at an angle to where it was last, and the blood spray has vanished.
When D'Arnot sharpens his straight razor before shaving Tarzan for the first time, a close-up of his hands shows him repeatedly flipping the straight razor the wrong way across the leather strop, blunting the blade. A 19th Century gentleman explorer of the would never make such a mistake.
In some of the jungle scenes the braying of zebras can be heard. Zebras do not live in jungles.
The cognitive and speech centers of the brain shut down if they are not stimulated. After a certain age, Tarzan wouldn't have been able to say more than a few words, let alone learn two entire languages.
In the trading post after Tarzan is convinced to return to England to find his family, he and the Belgium explorer (Ian Holm) encounter a group of men drinking and playing cards. There are various animals in the room and one of the card players has a squirrel monkey on his shoulder. Since they are in Africa this would be highly unlikely as squirrel monkeys are native to South America. Unless the card player traveled from Central America to Africa it would not be possible to see a squirrel monkey in Africa.
The flamingoes seen in the deep jungle are completely out of place. They live in lakes that are rich in a certain type of red algae, which, incidentally, is why their plumage is pink.
When the story begins in the 1880s, young Jane Porter (Alison Macrae) is playing with a mechanical plush-toy monkey that holds a cymbal in each hand, and the monkey bobs its head as it repeatedly bangs the cymbals together. Such cymbal-banging monkey toys were first manufactured in the 1950s.
Tarzan's hair gets shorter as he gets older, before he ever finds the knife to cut it with. As an adult, his hairstyle changes frequently in the jungle.