Answer:
Explanation:
<u>Horses</u>:
<em>Common characteristics with primates</em>:
- Hair: Most mammals have hair with different functions, depending on the animal and the body area they are covering. Horses hair provides insulation, thermal regulation, protects the skin against elements such as wind, sun, rain; serves as camouflage, assists in sensory perception and transport of pheromones. It also protects against insects and serves as a barrier to chemical, physical and microbial invasion to the skin. Hair can take on several different forms depending on their function. Horses have three different kinds of hair: permanent hair, temporary hair that covers most of the body, and the tactile hair on the muzzle and the ears.
- External ears: As primates, horses have external ears that direct external sounds from the environment to the tympanic membrane. The auricle is the visible portion of the outer ear and can be a strong indicator of the mood of the horse. It is created by cartilage, a thin covering of skin and muscles attaching to the base.
<em>Primate traits that they lack</em>:
- Fingers and toes: Horses do not have fingers and toes as the other mammals. Instead, they have one toe. The pedal bone, which is a hoof-shaped structure in feet, serves for the attachment of tendons and ligaments from the muscles in the forearm. This is the biggest and most important hoof bone.
- Short Nose: Primates suffered a progressive reduction in nose size over time. They have small noses compared to horses, whose sense of smell is much better due to their bigger nose.
<u>Dolphins</u>:
<em>Common traits</em>:
- Mammary glands: These glands consist of ducts and glandular tissues that secrete milk, which provides young with the nourishment that they need to grow, like proteins, sugars, fats, vitamins, and salts.
- Anterior limbs: Dolphins anterior limbs are the flippers. They share the exact same bones with primates, but with shape and size modifications, depending on the species. They have five phalanges, carpals, ulna, and radius and short humerus bones.
<em>Primate traits that they lack</em>:
- Nipples: As all mammals, dolphins have mammal glands that secrete milk, providing young with everything they need to grow. Unlike all mammals, dolphins do not have nipples; instead, they have a slit on each side of genitals where the mammary glands are located. Whenever the baby hits the slit, it stimulates the gland and produces the milk ejection.
- Heterodoncy: As dolphins do not chew their food they haven´t developed heterodont dentition. They have homodont dentition, as they just use their teeth for caching their prey or competition between mails.
