The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. Which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant?

#Question id: 11280

#Unit 10. Ecological Principles

Ecosystem services include processes that increase the quality of the abiotic environment. Which of the following processes would fall under this category?

#Question id: 11281

#Unit 10. Ecological Principles

Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses 2,500 J for cellular respiration. What is the production efficiency of this owl?

#Question id: 11282

#Unit 10. Ecological Principles

Which of the following ecosystems would likely have the largest net primary productivity per hectare and why?

#Question id: 11283

#Unit 10. Ecological Principles

Herbivore ingests plant material with 1000 k j energy form producer and assimilated only 200 k J energy in their blood stream; additionally herbivore invests 120 k j energy in their maintenance. What is production efficiency of that herbivore?

#Question id: 11284

#Unit 10. Ecological Principles

Which of the following could qualify as a top-down control on a grassland community?

#Question id: 11285

#Unit 10. Ecological Principles

Terrestrial herbivores are animals that eat only plants and their digestive systems contain microbes that aid in the digestion of cellulose, Carnivores eat primarily animal flesh or fluids. Which of the following is correct is correct statement?