Photosynthetic Animals – Nature’s Evolution Not Anomaly

Three Toed Sloth:
Sloth has a photosynthetic fur. It’s fur is brown but, due to rainy and moist conditions the fur acquires a green color because of heavy colonization by green colored algae named Trichophilus Welckeri which shares a symbiotic relationship with the sloth. The algae needs high temperature to thrive, and the sloth’s fur hosts an ideal living condition for the same. The algae enables the folivorous sloth to camouflage with it’s sylvan surroundings which protects it from it’s carnivorous predator Harpy Eagle. Sloth draws essential nutrients from algae via diffusion. The sloth’s diet is augmented with availability of algae.

Sloth

List of known photosynthetic animals:
Chloroplasts are the photosynthetic organelles that absorb the sunlight to produce energy and glucose in plants, these are plastids present only in plants and algae, but, below are some exceptions in the animal kingdom.

Sea Slug – Elysia chlorotica

Sea Slugs

Sea Slugs are capable of staying without food for nine months. The sea-slug eats an algae named Vaucheria Litorea. It not only feeds on algae but, also steals away the algae’s chloroplast and genes this is known as Kleptoplasty (stealing plastids in Greek).
The digestive system of sea-slug is not complex and evolved as humans so, whatever it eats is engulfed as whole forming a cell pouch in it’s intestinal lining which enables the integration of algae’s chloroplast into it’s own cell.
The sea-slug accepts photosynthetic genes from algae by Horizontal Gene Transfer. The horizontal gene transfer takes place in lower life forms like bacterias where the genes are passed on to other organisms even when one is not the offspring of another.

Spotted Salamander – Ambystoma maculatum
Spotted Salamander

Algae can be found in the Spotted Salamander’s developing embryos which perform photosynthesis and serve as an extra source of energy for the growing and developing embryo. The eggs are transparent so as to allow the infiltration of sunlight which is absorbed by the algae in the embryo to perform photosynthesis. In fully grown spotted-salamanders the chloroplasts of algae are present in the mitochondria of their own cells which act as an extra source of oxygen and carbohydrates via photosynthesis. In vertebrates any foreign material is destroyed by their robust immune system but, not so in Spotted Salamander, the algae is not foreign but shares a photosynthetic relationship.

Oriental Hornet – Vespa orientalis

Oriental Hornet

The Oriental Hornets don’t have borrowed chloroplasts in their bodies but, can absorb sunlight to produce energy. These insects have yellow bands in the cuticle of their exoskeleton which have a yellow pigment called xanthoperin which enables absorption of sunlight and converts it to electricity.

Pea Aphid – Acyrthosiphon pisum

Pea Aphids
Pea Aphids feed on leguminous plants. Pea-Aphids can produce carotenoids, which are pigments usually produced by plants, fungi and microorganisms. Carotenoids give color to the pea-aphids. The carotenoids help pea-aphids to absorb sunlight and covert it to energy (adenosine triphosphate or ATP). Aphids in the cold produce high levels of carotenoids+ATP and are green, while optimal conditions result in orange aphids that produce intermediate levels of carotenoids+ATP, and white aphids with almost no pigment appear in large populations faced with limited resources.