Final answer:
The late Miocene epoch saw the spread of grasslands and a cooler climate, while at least one African ape genus, Proconsul, survived due to fossil evidence. Hominins include all species on the human side of the evolutionary tree, with 'potential hominins' first appearing in the late Miocene. The term 'potential hominins' is used because while these species exhibit some human-like characteristics, there is still uncertainty in their definitive classification.
Step-by-step explanation:
Environmental Changes of the Late Miocene and Survival of African Apes
The late Miocene epoch is notable for the transition to cooler and dryer climates, which brought about significant environmental changes. These changes included the expansion of grasslands and a decrease in tropical forests. This period, lasting from about 11.6 to 5.3 million years ago, saw the emergence of early apes such as Proconsul africanus, with fossil evidence suggesting adaptability to various terrestrial habitats.
We know that at least one African ape species survived through the Miocene due to fossil records, including those of the genus Proconsul found in Africa, displaying both ape-like and some primitive human-like characteristics.
Hominins and the Fossil Record
Hominins are members of the human lineage, including all species on the 'human side' of the evolutionary tree since diverging from the common ancestor with chimpanzees and bonobos. The first 'potential hominins' appear in the late Miocene fossil record, roughly between 10 to 5 million years ago. These potential hominins, such as Orrorin tugenensis and Ardipithecus kadabba, are referred to as 'potential' because they exhibit some, but not all, characteristics associated with later hominins, particularly bipedalism and dentition.
By the Pliocene epoch (5 to 1.8 MYA), however, fossils clearly indicate the presence of bipedal hominins and primitive cultural behaviors like stone tool use, marking significant advancements in human evolution.