Deadly L.A. wildfires have destroyed homes and businesses this week ... and the massive blazes have also upended local ecosystems to a horrifying degree.

Jeff Corwin tells TMZ ... right now the focus of the fires is -- properly -- on people dying and homes turned to ash. But, domestic and wild animals have also been severely affected in this "unprecedented catastrophe."

The famed biologist host points out there's only 350 California condors left in existence … “and a significant portion of the population lives in ground zero of the Palisades fires” -- so there is a chance they could end up nearly wiped out.

Bears and mountain lions also inhabited the burn areas – and JC says that means those that haven't been killed or badly injured may move inland for food, water and shelter ... possibly creating dangerous interactions with humans.

There's a chance as residents return to the burn areas to check their homes that they might encounter injured "large predators" and want to help ... but Jeff says that's a bad idea. In that situation, keep clear and call the proper authorities.

The fires have also killed or displaced thousands of dogs, cats, and horses. JC advises people trying to find their lost pets -- the animal will likely return to the area of their former home … so set out food, water and a small camera.

Several organizations and shelters are helping impacted people who have pets ... including Jeff’s Brady Hunter Foundation ... which is donating $31K and is matching donations to facilitate pet needs.