This is a clarification on an important point raised during Rb Group 1’s discussion on reproduction in bees. Basically, there are three major types (or castes) of bees in a hive (could be more since bees have a very rigid social structure):
Queen bees have mating flights with 15-20 drones (haploid males) and store their sperm in a spermatheca (which can be accessed over long periods of time). These queen bees lay eggs that will either be a) fertilized with these sperm and develop into diploid queens-in-waiting and sterile worker bees or a) stay unfertilized and develop parthenogenetically into haploid drones.
How does an egg from a female develop into a male drone? This is because bees don’t define sexes the way we do. Humans define sexes genetically this way: females have two X chromosomes, males have X and Y. Bees define it using chromosome number: haploid bees are male, diploid bees are female. 🙂
The exam is over 45, passing score is 27.
We’re having this on the two days (Th and F) after the Perio. Cs will do it on Mar 12, Th afternoon at 230-4, Rb on Mar 13, F afternoon at 230-4. Let me know if you have problems with the schedule.
Per group, kindly prepare:
- 1 live frog or toad (can be obtained from UP NSRI @ around PhP50/frog) — please submit these to me on the morning of dissection day
As part of the prelab activity, please check out this virtual frog dissection link that will show you how it’s done. You can download the prelab sheet and procedure here.
If you have any ethical or personal concerns regarding any part of frog dissection: the use of live frogs, pithing (see second definition), etc., please leave a comment so we can plan around them. Thanks!
Link to Scientific American’s slideshow on love and optical illusions (sample pic below)
Reposting this youtube vid from last year:
Happy ❤ Day, everyone!