Your intro really brings me a lot of joy, Professor Dave. :)) Just wanted to point that out :>

Congrats on a million subs soon. Very well deserved, keep making more vids :) I love the way you break things down

Another solid episode, Professor Dave. Most of this is about 9th grade biology, but It has been a long, long time since the 9th grade. Nice refresher. Thanks!

your channel and startalk are a godsend on youtube.

A very good video to learn both English and Biology.

Thank you Dave, very well explained

Professor Dave please correct the cactus story - you show shoots and call them leaves! this way I cannot recommend your nice video to my students.

Thank you for the content!! I am so happy to have you teach about plants in this video, fantastic! Thanks Dave 😊

@Professor Dave Explains You're a great teacher, and all of these science lectures are both valuable and appreciated. But you know what the people want.

i really like ur videos they do help me in my school syllabus

*Interesting video.* Could you also do videos on *SOIL* ? I feel this topic is neglected in popular science channels - yet so important.

A fun note is that the pollen in order to fertilize the ovule need to "burrow" through the cells in the stigma. They essentially push their way through the intercellular space between cells until they reach the ovule. The rather annoying part for humans is that the pollen has no way to tell which cells it comes into contact with so it will attempt to push its way through any multicellular structure it comes into contact with that will allow it to keep burrowing. Although skin is usually pretty resilient, the mucus membranes (like in our nose) are not, so pollen will frequently burrow into our intercellular space. They don't actually do any damage to us but often, our immune system will take the intrusion as a threat and begin an immune response as most infectious bacteria will do the same. The annoying part is that the antibody selected will almost without fail be the E type antibodies which stick their back ends into mast cells and trigger a signaling cascade when they come into contact with their recognized pollen. This causes the mast cell to release histamines which causes uncomfortable swelling and redness more commonly called an allergic reaction. The current best guess (at least when I was earning my bachelors) is that the original use of the allergic response was to parasites as the red itchy swelling would cause it to be difficult for a parasite to cling on to the skin as well as causing scratching which might dislodge the organism. One of the main statistics of note that increases the probability that this is the correct answer is that the countries which no longer have enough widespread use of modern medicine that the are no longer endemic or frequent parasite infections are also the only countries that have widespread problems with allergies. It is thought that, because it is no longer being used for its intended purpose of parasite removal, the allergen system is malfunctioning in identifying nonharmful invaders like pollen as a threat Edit for a last note: Eosinophils (a type of white blood cell) are also found at the site of these anti-parasitic/allergenic responses but we currently have little understanding as to how they act and what their job is but they are thought to be the innate immune system's parasite specialist cells somehow geared towards damaging the multicellular bodies of parasites. I say somehow because, at least when I studied immunology, the mechanism for how they do this is unknown

Thanks bro this made me learn more about plants then 2 months worth of biology (plants) that my prof miss teach

Thank you for the lectures even during lockdown professor

... damn you're life-saver for my biology final exam 😂😂❤️ if only I knew about you before..

Well understood... thanks for that 😇☺️☺️

good work sir.

Wow thanks for this lesson

Thank you teacher

Dave explains everthing so clearly!

Thanks!

thanks a bunch!

you also show a dandelion seed head in the middle of your flower conversation, exemplifying anemophyly - what you show is anemochory

Thanks a lot

Really like your videos but the cactus shown is a photosynthetic stem not a leaf ( likely genus Cereus) Most cactus spines( I read not an expert) are modified leaves or bud scales. Prickly pears have tiny leaves on new shoots that dry up in a few weeks. Pretty sure there are some in the cactus genus with "real" leaves but it is not real common. White potatoes are modified stems not roots i am 99 % sure.. ( think sweep potatoes are modified roots but wouldn't risk anything valuable to bet on that. )

your explanations are so brief, but very clear. Thank you. Teachers in my nation lack the ability to explain teaching materials simply like this. Maybe I can make explanation based on your videos, or translate your teaching videos into Indonesian, if I may. I think that would be useful for students in Indonesia :D

4:27 just thought I'd mention here that those are not leaves on cacti, those are stems that have been modified for water storage and photosynthesis! The leaves of the cacti were modified into the spines , hence why the stem had to modify to be photosynthetic. Succulents on the other hand, do have modified leaves for water storage.

Can anyone tell me, is there a difference between the term carpel and pistil?

What is a starch exactly, just a complex carbohydrate? What kind of cell structure do tubers have? Is it storage for the next generation or is it returned to the parent plant?

Maybe your math playlist should be named “Math With Professor Dave”

Nice👍

cool video. Potatoes are stem tubers but your graphics seem to suggest they are root tubers.

Taraxacum officinale as wind-pollinated less showy flowers... ... seed head, an odd mistake, oops : ))))))

i've learned easily from your videos god bless you

More plants!

0:32 "shoot system" Me: *golden laser pew pew*

Great video 📹. Ps nice haircut 💇🏻 👍

rootin' shootin' tootin'!

Professor Dave, doesn’t the illustration in the insert at 01:55 show a deciduous tree instead? I thought perennials didn’t drop their leaves.

great

starch storin' stubers! rising rhizomes! i'm not high!

4:24 Is that a pawpaw? Im trying to grow them in my backyard with my dad :)

yo dude the green parts on cacti are stems not leaves, the leaves are the spikes

i still love rewatching the flat earther video's. proffesor dave just ABSOLUTELY ANIHILATED that community. LOL

Examples of eudicots who doesnt show secondary growth

Tubers are not a part of the roots, rather a modified stem

sir i had miled you to do world history plese do look on that sirr this vedio is super thank you hope you do

4:28 "fat wax covered leaves on succulent plants like cacti".....aren't cacti known for having modified spine leaves and storing water in their stems ...?

🎉🎉

hi sir , your such a great help.. allow me to call all your posts are heroic

I want to join willibe able to go to the lessons I need to. Cover again

You Are a god

Do you have any tips on how to “get into” science with no background in science what so ever? Where to start

Does cancer infect tree

So are plants that have ryzomes all one organism? For example the grass in my area has these. So is one root and ryzome all one big plant and if so is there a limit to the size of one plant?

I understand you more than my teacher, l appreciate ❤

You are much much intelligent please make a complete series on course PLANT ANATOMY(explains axial ray systms n flower development etc) videos of undergrad level

wait tubers are modified stem not roots.

can you Explain how cannabis works and why

فرٹیلازیشن کے بعد پھل پودے کی Ovary سے پیدا ہوتا ہے ۔۔۔۔۔کیا یہ معلومات درست ہیں؟؟؟؟

I like u most

Dave in. D.

TYG

wooow my comment is in top 15

:)

1st

Arnt rhizomes the worst? I hate all those weeds that do this.

You're starting to look like the younger of the two Jehovah's Witnesses that comes around my house once a year. Good video anyway.