“This painting is called Fish Swimming Amid Falling Flowers. It was painted during the Song dynasty, around a thousand years ago by a man called, Liu Cai. Peaceful, huh?”

The watercolor showed some sort of variety of carp in a pond, swimming through colorful floating blossoms.

“The Chinese have been cultivating the carp species for centuries – has a great reputation for being hardy, and a talent for eating pond weed, which was a huge problem for us in many of our waterways.” She shrugged. “You can eat them, they look attractive, low maintenance, and some can live for nearly a century.” She changed the slide to two men holding a single fish in the air – it was a giant.

“The problem was, they liked our waterways so much, they multiplied, and grew big – up to one hundred pounds each. And then they decimated every other living thing in the waterways. In fact, in the Illinois River today, they account for ninety per cent of the entire biomass. Bottom line: once the carp moves in, everything else either moves out, gets eaten, or starves.”

She gave the room a flat smile. “Forget climate change; the estimated damage from invasive species worldwide totals more than $1.4 trillion – annually.”

Cate leant forward onto her knuckles. “A habitat that took millions of years to become established can be irretrievably altered in twelve months.” She paused a beat, drawing all eyes back to her. “That’s why today, there are such rigorous checks and balances on what we allow into our country, into our forests, and our airways, and into our rivers.” She looked at each of the students. “I’m your original green warrior, but even I know that there are some creatures that do not deserve to exist in some areas – they’re aliens, deadly invaders. And if they can’t be moved on, then eradication is the only solution. Or one day, we might find something moves in, that even threatens us.”

Cate let the silence hang for a second or two, before shutting the images down. She then took a few questions, set an assignment, and finally dismissed her class.

Greg jogged down the steps towards her. “Professor Granger.”

She grinned. “Professor Jamison. What brings you to my class? Trying to spark a few ideas for your own sessions?”

“Great presentation.” He leaned on her desk. “I would have mentioned the Australian cane toad or the gray rabbit waves of the 1800s. Still, overall I think you covered the topic in excellent detail.” He held up a finger. “But I am here to remind you not to forget our meeting with Bill later today.”

“Sure. Got a few errands to run, but I’ll be there. You know how I love bureaucracy.” Cate pretended to put a finger down her throat.

“Hey, who doesn’t?” Greg rolled his eyes. “Just don’t be late; you know how Bill gets. Besides, he said he had something important to discuss with us.”