I just wanted to say thank you Hank and the Crash Course team. I've used most of your videos as a study tool for my college Biology class. They've really helped me a lot.
The arrows in your food web (6:40) are pointing the wrong direction. Arrows should point from what is being eaten to what is eating it… just as the energy flows.
Crashcouse, thank you. I'm a senior in high school and taking AP Environmental Science. I read the book and listen to the lectures, but these videos definitely help reinforce what the concepts. I'm actually starting to look forward towards the exam in May!
The quality of this channel amazes me. I've showed it to numerous professors of mine, and they all love it. Many of them have even taken to using it in lectures on occasion
I only occasionally comment stuff on youtube. And I never wrote something like "I Love what you guys do!". Well anyway: I Love what you guys do! Concise, very fine with many different topics summarized in a captivating efficient way. As a scientist myself I think your videos are of great use as a general "textbook" approach to the field of ecology not only for the use of students, but teachers and researchers alike. As a youtuber myself, I hope these type of videos might help presenting the natural sciences field in a more, interesting, funnier, "easier to understand" way so we can use the incredible knowledge we are able to generate, in a more efficient societal way.
Hank, thank you so much for discussing bioaccumulation (biomagnification). I wrote a lengthy review article on methyl-mercury in Aquatics ecosystems and how it travels and influences each level in the food web. It is a complicated idea that I have had to explain to many of my students many times, but it is an important concept. Like birds of prey and wolves, etc., humans are also a top predator, and this is a major health concern as well as a major environmental concern. Thank you!!!
5 years ago, I came here during my undergrad need a crash course, left a comment, and left. 3 years ago, I was during my masters and needed a refresher and watched this again. I also left a comment and left:DNow I'm doing a PhD in food webs and am back here again. Am I just enjoying this video or have I just not learned anything in 5 years? I don't know. Let me see if I'll come back in 2025 when I should be a Dr. lol
Thanks bud I love these videos! I’m a safari guide in South Africa and this really helps me to gain a better understanding of all the cool stuff around me!
I wish things like this would be played on TV in place of 'news' emphasizing all the violent happenings in the headlines 24/7, in turn likely leading to more violence. Think about how much better a state we'd be in. Just a thought. Also, thank you Hank!
This was one of the better videos, in my opinion at least. I really liked how you made the argument of being better to eat from the lower food chain. It never occurred to me that the toxicity rises as you go up the food chain(this is how I understood bio-accumulation). Does this mean that humans are toxic or would be toxic for an animal which would primarily consume humans?
Bioaccumulation is actually the amount of a pollutant accumulated by 1 organism. Biomagnification is when a pollutant moves up the food chain getting progressively larger in quantity in each organism as it rises in trophic level (what Hank described with the mercury), easy mistake though ! :) yay for learning!
thank you so much hank and the crash course team, i watched your videos during GCSE's then again in my A levels before covid stopped us from sitting the exams, and now i sit here editing my dissertation for my uni degree. thank you so so much for being quicker and better at explaining stuff than half of my teachers. i wish you all the best! :D
Wow, I didn't know that berries eat bears! Or that salmon eat bears! It's been commented before but the food web's backwards, the arrow's supposed to point to the thing that's doing the eating, not the thing getting eaten.
Not sure if you got a response: -Ecology looks more into the interactions between organisms and other organisms and environmental factors, and ultimately how they influence each other. -Environmental science is the term used to describe how all biological and physical sciences work together as a system. The scope is huge: some of the basic things that tend to be included are biology, geology, oceanography, meteorology, ecology, even economics. The real difference between two is the scope.
Not all organisms that are autotrophs photosynthesise. There are some which perform chemosynthesis, usually small bacteria that gain energy by breaking molecular bonds and collecting the energy released.
A small note: Most professional ecologists draw food chain / web arrows in the direction of energy transfer, not who is eating whom. So the arrow should go from the fish to the bear because that's the direction of the energy flow.
There is always a producer, but it doesn't have to be a plant (or other photosynthetic organism.) In the case of the deep sea vents, it's chemosynthetic bacteria. In all cases, it's something that takes inorganic materials and/or energy from the environment and makes something edible.
Correct me if I'm wrong - this food web is shown incorrectly. The arrows are pointing in the wrong direction (they point in the direction that energy flows). Right?
The Magic Eye thing is hard!! I think I have it though: There's a horizontal/vertical cross which is medium distance. Then at the top left there's a 'mountain'. At the top right there's a 'valley'. Bottom left is another valley. And at the bottom right there's a circle that's so close it scares you the first time you see it :-P
Pop music is generally describing a line between so called 'art' or classical music, functional music (liturgical and educational), and the music that is consumed by the large masses. Much of the old music that we now consider classical was once pop much including most operas. Much like ecosystems the lines are often blurry and ill-defined.
One comes to mind: caves where all the energy in the system comes from bats flying out, then returning and leaving lots of guano. Bugs live on the guano, bigger animals eat the bugs, etc.
(2) --> If it's a separate mechanism, it's strange. The problem with being killed and eaten is, obviously, the "being killed" part - once you are dead, it's secondary if you're eaten or buried. So I wonder why earthling evolution developped a "don't eat each other" mechanism instead of a "don't kill each other" mechanism. But the mechanism may have developped much earlier in the evolution of animals in order to prevent predator from self-extinction - a "don't hunt each other" mechanism. --> (3)
Sometime pop is a genre within all popular music and is short for bubblegum pop. This genre is mostly defined by what it's not. It isn't rock, country, hip hop, jazz, but it's still clearly popular music.
Interesting point! Assuming that by earthlings you mean the most widespread of the planet's primate species (or any other earth species that live in colonies), the toxin accumulation hypothesis is an appealing one, however, let me offer an alternative hypothesis: They all (most at least) seem to have managed to enter a pact in wich they agree to not eat each other in exchange for not being eaten. For non-social animals, the cost of combat might be the prevalent factor. I welcome your criticism.
