前回の記事で、ひとまずTOEFLのリスニング・パッセージのドラフトを作るところまでをシェアした。今回はそれを推敲するパートにしたい。

レクチャーであれディスカッションであれ、TOEFLのリスニングで講義がいきなり始まることは滅多にない。たいていの場合、前回の授業のおさらいやホームワークの確認など、なんらかのアイスブレイク的なことから始まる。

今回のキツツキの話だと、ecology または environmental science だろうか。ただ、ＣＪがパッと思いつくアイスブレイクというか導入部分は、

教授
「先週まではキーストーン種について学んできた。誰か、キーストーン種とは何か、簡単に説明してくれたまえ」

女子学生
「はい。キーストーン種とは云々かんぬん」

教授
「素晴らしい。それでは今週よりテキストの新しいチャプター、生態系エンジニアに入っていく」

みたいな感じである。キーストーン種もTOEFLでは時々出てくるトピック。キーストーン種と生態系エンジニアを両方扱うクラスとなると、生態学になるかな。授業の出だしはこんな感じか？

Professor:
All right, class, settle down. Up until last week, we had been discussing many examples of keystone species. Today, we will be getting into a new chapter. But before we do that, can someone reiterate the definition of a keystone species?

Female Student:
Um, a keystone species is like, a species that has a huge impact on everything around it even though there might not be many of them. This species helps maintain the structure of the whole ecological community. Without these keystone species, the whole ecosystem would change or even disappear.

Professor:
Right. So, give us one example of a keystone species and talk concisely about its impact on the environment. Caleb?

Male Student:
Ah, one good example of a keystone species is elephants. They are not a majority on the savanna, but they are responsible for keeping trees from growing. Without them, the savanna could soon turn into a forest.    

Professor:
Very well. 

ＣＪは自分が大学の非常勤講師でもあるので、授業を半期15回あるいは14回の中の一つと位置付けて考えるし、実際のTOEFLのリスニングもそうなっていることが多い。事実、ＯＧには「実際の講義を録音して、それを基にスクリプトを作って、録音している」みたいに書いていたりする。なので、こういう始まり方は、まあまあ現実に即していると言えるのではなかろうか。

今度はこれを使って、ChatGPT や Google Gemini を働かせてみる。上の出だしの教授と学生のやり取りを呼び水に、再度、リスニングのスクリプトを書かせてみる。プロンプトは

Above is a conversation between a professor and his students at the start of an ecology class. Could you complete this lecture/discussion using the lecture passage you created at my request, the one about how woodpeckers are excellent ecosystem engineers?

としてみる。そして結果は・・・？

ChatGPT のアウトプット

Professor: Alright, now that we have a clear understanding of keystone species, let's delve into the fascinating world of ecosystem engineers. As we've learned, keystone species have a disproportionately large impact on their environment, but now we're going to focus on a specific type of keystone species called ecosystem engineers. These are species that directly or indirectly modify their environment, shaping the landscape and influencing the distribution and abundance of other organisms. Can anyone give me an example of an ecosystem engineer?

Female Student: Um, professor, I think woodpeckers could be considered ecosystem engineers.

Professor: Excellent observation! Woodpeckers are indeed prime examples of ecosystem engineers. They play a crucial role in shaping forest ecosystems through their unique behaviors and adaptations. Now, let's explore how woodpeckers engineer their environment.

Woodpeckers, with their specialized beaks and drumming behaviors, create nesting cavities in trees. These cavities not only serve as homes for woodpeckers but also become invaluable real estate for a variety of other forest inhabitants, including owls, squirrels, and various bird species. These secondary cavity-nesters benefit from the structures carved out by woodpeckers, finding refuge and opportunities to raise their young within these sheltered confines.

Furthermore, the excavation activities of woodpeckers can lead to the creation of deadwood, which serves as habitat for numerous species of insects, fungi, and microorganisms. These decomposers play essential roles in nutrient cycling and soil formation, contributing to the overall health and productivity of the forest ecosystem.

In addition to creating nesting sites and deadwood, woodpeckers also indirectly influence plant diversity and distribution. By foraging for insects and larvae beneath the bark of trees, they help regulate insect populations and prevent pest outbreaks. This natural pest control mechanism can promote the growth of healthy trees and contribute to the maintenance of ecosystem balance.

So, as we can see, woodpeckers are not just skilled foragers and nest builders—they are also ecosystem engineers, actively shaping their environment and influencing the abundance and distribution of other organisms within the forest community.

Male Student: Wow, I never realized woodpeckers had such a profound impact on their environment. It's amazing how interconnected everything is in nature.

Professor: Indeed, nature is full of intricate relationships and dependencies. By studying the roles of species like woodpeckers as ecosystem engineers, we gain a deeper appreciation for the complexity and resilience of ecosystems.

Alright, let's move on to the next topic in our discussion. Thank you for your contributions, everyone.

Google Gemini のアウトプット

Professor: Right on, Caleb. Elephants are definitely a powerful example. Now, let's transition into our new chapter, which delves into the fascinating world of ecosystem engineers. These aren't just VIPs in their ecosystems, they're the architects, the carpenters, even the landlords! Can anyone guess who might fit this description?

Female Student: Hmm, maybe beavers? They build dams and change the whole landscape.

Professor: Interesting thought! Beavers are definitely ecosystem engineers, but today we'll be focusing on a feathered friend – the woodpecker. Don't let their drumming fool you, these birds are silent builders with a hidden talent for shaping their environment. Now, remember what we discussed about keystone species – their impact on the ecosystem was much bigger than their numbers. How do you think woodpeckers might fit this mold as ecosystem engineers?

Male Student: Maybe they eat a lot of insects and keep them in check?

Professor: You're on the right track! But their influence goes far beyond pest control. Their specialized heads, like hammers and chisels, allow them to excavate intricate cavities in trees. While these are primarily used for nesting, their impact extends far beyond their own needs. Imagine these cavities as tiny apartments – who else might benefit from them?

Female Student: Oh, maybe other birds looking for homes!

Professor: Exactly! Owls, squirrels, wood ducks, even flying squirrels – all find refuge and raise their young in these woodpecker-made havens. Talk about unintentional landlords! But the story doesn't end there. Remember, woodpeckers aren't known for their gentle touch. Their drilling weakens trees, eventually leading to their demise. But fear not, nature lovers! This "destruction" becomes an opportunity for others.

Male Student: So, the fallen trees become food for decomposers like insects and fungi?

Professor: Precisely! These decomposers break down the wood, releasing essential nutrients back into the soil, fueling the growth of new plants. This cycle of creation and decomposition, all kickstarted by the woodpecker's initial "damage," keeps the forest ecosystem healthy and thriving.

Female Student: Wow, I never knew woodpeckers had such a big impact! They seem like small birds, but they play such a crucial role.

Professor: Exactly! They're a perfect example of how even seemingly insignificant creatures can be vital ecosystem engineers. So, the next time you hear their drumming, remember, it's not just a song, it's a symphony of ecological influence. Now, let's delve deeper into the fascinating world of woodpeckers and explore more examples of their engineering feats.

今回だと Gemini の方がちょっと出来がいいかな？というかＣＪ好みかな？これをまた色々と手直ししなければならない。教授は自分からキツツキの pecking/drilling が木にダメージを与えて死なせてしまうことに言及しているが、ここは本来なら学生が質問すべきところ。次回はそのあたりのやりとりを作っていってみたい。