Early Hominins Flashcards
What order is a Hominin under and what else is under that order?
A hominin or hominini is under Tribe under the order Primate. Chimpanzees and Fossils that connect us to our ancestors and chimp relatives are also under this.
What connects us to our closest living relatives, the Great Apes?
Bipedalism.
What is a Hominin?
A Primate category that includes humans and our fossil relatives since our divergence from extant great apes.
What are Hominins Ancestral Traits?
Being Dental Apes and Arboreal Suspensory Locomotion.
What are traits that relate to Arboreal Suspensory Locomotion?
A flexible lower back and rotating shoulders.
What are Hominins Derived Traits?
Bipedal Locomotion.
Are humans included in the term Dental Apes?
Yes.
What is the characteristic of a Dental Ape?
A Y-5 cusp which means cusps 2 and 3 are touching.
Can there be fewer than 5 cusps?
Yes there can be a Y-4 cusp pattern.
Can Dental Apes have parallel cusps?
No. Only other animals.
Do new world apes have large canines?
No.
True or False: Baboons do not have canine dimorphism.
False. Baboons have extreme canine dimorphism.
What is a diastema?
A space between the teeth, usually for large canines to fit when the mouth is closed.
What is a Sectoral Premolar?
It cleans the canines and keeps them healthy. It also makes space for them and sharpens them.
Do humans have a wider or narrower dental arcade than primates?
Wider.
What is a Parabolic Dental Arcade?
A U-shaped or parallel dental pattern in primates.
List 5 things that separate the Human Dentition from other apes.
- Smaller canines
- No diastema
- No sectoral first premolar
- Relatively small incisors and large molars
- A wider dental arcade
What are the ancestral traits of Arboreal Quadrupedal Locomotion in Hominins?
- grasping hands and feet
- wide ribcage
- triangular shaped scapula
- scapula covers the back
- long hindlimbs
- Plantigrade walking (heel touches the ground)
What is another word Suspensory Locomotion and what is it?
Brachiation (swinging from tree to tree).
What are traits of Brachiation?
- Rotating shoulder joint
- Flexible wrists
- Curved fingers (phalanges, tarsals, and metatarsals are curved)
- Extending elbow
- Rounded ribcage
- Short lower back
- Long forelimbs
What primates have really long arms and use them to balance while walking bipedally?
A Gibbins.
What is a new trait in hominins?
Having a short and wide bowl shaped pelvis.
What are traits of Bipedal Locomotion?
Having a suspensory upper body which includes
- rotating shoulder
- flexible wrists
- round ribcage
- extending elbow
- short lower back
And a Derived Pelvis which includes
- a short and bowl shaped pelvis
- a short and wide sacrum
What change does Bipedalism cause to the Foramen Magnum?
It moves it to directly under the skull instead of at an angle.
What is the Foramen Magnum?
The large hole at the base of the cranium, through which the spinal cord enters the skull.
