Why do certain characteristics make a species more susceptible to extinction?

[Swetasuria]

It was given in my school textbook that large body size, small population size, low reproductive rate, feeding at high trophic levels, fixed migratory roots and habitats and localised and narrow range of distribution are the characteristics susceptible to extinction.

I don't understand how feeding at high trophic levels and large body size could help in extinction of a species.

I have learned that arthropods can survive better because of its jointed appendages and protective covering. Does their small size help them too? Also, I didn't understand what they meant by saying 'feeding at trophic levels'.

 

[HallsofIvy]

Did you look up 'trophic level' to see its definition? 'Feeding at a high trophic level' means 'feeding high on the food chain'. A plant can survive on water, air, and sunlight and will survive as long as those are sufficient. An herbivore eats plants so has to have all those, so the plant will survive, and a relatively low level of other herbivores. A carnivore has to have herbivores surviving so need plants to survive but also needs a relatively low level of other carnivores. The higher on the 'trophic level' you are, the longer and more fragile your 'food chain' is.

Also, it should be clear that the larger you are, the more food you need and the more you will be affected by drought or other scarcity of food.

 

[Swetasuria]

Did you look up 'trophic level' to see its definition? 'Feeding at a high trophic level' means 'feeding high on the food chain'. A plant can survive on water, air, and sunlight and will survive as long as those are sufficient. An herbivore eats plants so has to have all those, so the plant will survive, and a relatively low level of other herbivores. A carnivore has to have herbivores surviving so need plants to survive but also needs a relatively low level of other carnivores. The higher on the 'trophic level' you are, the longer and more fragile your 'food chain' is.

Also, it should be clear that the larger you are, the more food you need and the more you will be affected by drought or other scarcity of food.

Right, thanks!