4-H Embryology Initial Classroom Presentation
Calvin DeVries and Vicki Jedlicka
Author
04/02/2020
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Description
This is Nebraska Extension in Lancaster County’s initial presentation given in local classrooms as a part of the 4-H Embryology school enrichment program. The presenter explains what Embryology is (i.e. the “study of” + “embryos), what fertilized eggs need to properly incubate (i.e. heat, humidity and rotated an odd number of days) as well as the parts of an egg. After answering student's questions, the presenter normally places a dozen fertilized eggs in the classroom incubator!
You may watch eggs hatch on 4-H EGG Cam at lancaster.unl.edu/eggcam!
Locally, the 4-H youth development program is a partnership between Nebraska Extension and Lancaster County government. Learn more about the Lancaster County 4-H program at lancaster.unl.edu/4h.
Searchable Transcript
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- [00:00:00.019]Hello my name is Calvin DeVries and
- [00:00:01.745]I specialize in the 4-H Youth Development
- [00:00:03.740]Program for Nebraska Extension in
- [00:00:05.390]Lancaster County and today I'm going to
- [00:00:07.780]talk with you about embryology. So some
- [00:00:10.622]of you may have heard the ending of this
- [00:00:12.942]word in your science class at the ending
- [00:00:16.356]being ology you may have heard the term
- [00:00:18.700]biology, geology or something like that
- [00:00:21.086]but the term biology is the study of life
- [00:00:23.103]and we're going to further break it down
- [00:00:25.941]and study embryos. So an embryo is the
- [00:00:29.655]very first stage of life. So all plants,
- [00:00:33.398]animals cats and dogs, myself and you
- [00:00:35.956]as the viewers start out their life as an
- [00:00:38.754]embryo. And the ending here ology
- [00:00:42.748]means the study of. So we're going to
- [00:00:45.834]be studying embryos. And to do this
- [00:00:49.740]we're going to place fertilized eggs in an
- [00:00:52.098]incubator to have you view the 21-day
- [00:00:56.012]developmental process of a chicken embryo.
- [00:00:58.912]So these eggs are special and they come
- [00:01:02.819]from a farm that have both hens and
- [00:01:05.202]roosters so they are going to be
- [00:01:07.052]fertilized. The rooster being the male
- [00:01:09.774]and the hen being the female so on those
- [00:01:12.955]farms those eggs are fertilized and when
- [00:01:16.040]placed in the incubator in 21 short days
- [00:01:18.495]we will have chicks hatching live. But to
- [00:01:22.554]get to this point of an actual hatch there
- [00:01:25.653]is three really important things we need
- [00:01:27.564]to do caring for the eggs in the
- [00:01:29.184]incubator. The first being monitoring the
- [00:01:32.750]temperature by using a thermometer
- [00:01:35.645]placing it on the inside and we're going
- [00:01:37.819]to do the best we can to keep it at a
- [00:01:39.628]perfect 100 degrees. That is due to the
- [00:01:43.200]fact if the mother hen were to be sitting
- [00:01:45.686]on that eggs on the farm that's her
- [00:01:47.706]natural body temperature. So if she
- [00:01:50.069]were to be sitting on them on the farm
- [00:01:51.894]she would fluff up her feathers and sit
- [00:01:53.867]on multiple eggs at one time but while
- [00:01:55.779]utilizing the incubator we're going to
- [00:01:57.690]monitor daily by checking our incubator
- [00:02:00.044]making sure our incubator is reaching
- [00:02:01.885]100 degrees. Now the second most
- [00:02:05.826]important thing is turning the eggs. So
- [00:02:09.380]we need to turn the eggs as that embryo
- [00:02:11.573]is not strong enough to turn itself on
- [00:02:13.449]the inside egg on its own until day 18.
- [00:02:17.501]So if you view live on the 4-H Egg-Cam
- [00:02:21.082]we will have automatic turner's that will
- [00:02:23.104]look yellow that'll be naturally turning
- [00:02:25.126]it three times a day but if we were to do
- [00:02:27.523]it live in a classroom we would be turning
- [00:02:30.149]them by our hands. So we'd place an X
- [00:02:34.329]on the side of the shell to help us
- [00:02:36.787]monitor how many times a day and which
- [00:02:38.781]direction we we're flipping those eggs by
- [00:02:41.338]placing the X up and the X down three
- [00:02:45.824]times throughout that cycle in the
- [00:02:47.595]classroom but if the mother hen were
- [00:02:49.604]to be doing it on the farm it would be
- [00:02:51.743]her natural instinct so she would be
- [00:02:53.760]born knowing how to do that three
- [00:02:57.264]times a day but since she doesn't have
- [00:02:59.374]the luxury of hands she'd be utilizing her
- [00:03:01.948]beak and her toes so she'll naturally turn
- [00:03:05.507]them three times a day. But we also need
- [00:03:09.048]to monitor humidity levels in our
- [00:03:11.225]incubator and that is due to the fact that
- [00:03:14.427]moisture or humidity in the air needs is
- [00:03:17.434]required for those embryos to develop
- [00:03:19.426]and develop correctly. So if we were to
- [00:03:22.233]hold an egg we would recognize that
- [00:03:25.093]there's really tiny holes or pores all
- [00:03:28.730]over the egg shell. Now to compare
- [00:03:31.149]to our skin our skin has pores as well.
- [00:03:35.226]So in the winter months when our skin
- [00:03:37.495]gets dried and cracked we add lotion to
- [00:03:40.120]them and then they look soft and healthy
- [00:03:43.442]again. So now if we go back to our
- [00:03:45.237]incubator when we add water at a
- [00:03:47.008]hundred degrees it'll evaporate to
- [00:03:49.539]create humidity and that humidity will
- [00:03:52.338]enter and exit the pores of the egg shell
- [00:03:55.707]just like lotion would do moisturizing our
- [00:03:57.983]hands. So while that water is entering the
- [00:04:02.376]shell it's keeping the very first layer on
- [00:04:04.682]the inside or the shell membrane nice and
- [00:04:06.855]soft which will make it really easy for
- [00:04:09.268]when that embryo or that chick gets ready
- [00:04:11.777]to hatch on day 21. Now if we go back to
- [00:04:14.899]the example where we put lotion on our
- [00:04:17.321]hands to moisturize our skin if we weren't
- [00:04:19.691]to put water in our incubator that shell
- [00:04:23.157]membrane would be very hard and it
- [00:04:25.061]would be hard for that chick hatch on
- [00:04:27.313]day 21. Okay so now let's talk about
- [00:04:30.411]what's going on inside of our eggs today.
- [00:04:33.509]So on the inside of our egg at the very
- [00:04:35.529]top or the larger end of the egg we find
- [00:04:39.715]the Air Cell and so when that chick gets
- [00:04:43.037]ready to hatch on day 21 it'll peck all
- [00:04:45.846]the way around the top of that Air Cell in
- [00:04:48.352]a perfect circle taking its first breath
- [00:04:50.910]and then piercing through the shell
- [00:04:52.693]exiting on day 21. And if we move in a
- [00:04:56.380]little bit further remember our example
- [00:04:58.759]that we're creating humidity in our
- [00:05:00.535]incubator this is that Shell Membrane that
- [00:05:03.325]we're keeping really nice and softer when
- [00:05:05.351]that chick gets ready to hatch. If we
- [00:05:08.058]move a little bit further in we find the
- [00:05:11.402]Albumin or the Egg White. The Egg White
- [00:05:15.632]scientific name is the Albumin. If we move
- [00:05:19.800]a little further in we have the Yolk.
- [00:05:22.792]That'll be that really big round yellow
- [00:05:25.607]circle on the inside of our egg. And to
- [00:05:29.081]keep everything in place we have what we
- [00:05:32.682]call Chalaza providing the egg structure
- [00:05:35.619]just like bones do in our body so if we
- [00:05:39.177]were to be turning them we would need
- [00:05:41.205]to be really careful handling them not to
- [00:05:43.372]shake or drop them because that could
- [00:05:45.371]disrupt those Chalaza. But our eggs
- [00:05:48.598]remember are special so they have a
- [00:05:51.368]certain structure called the Germinal Disk
- [00:05:54.107]or Germ Spot. So that is going to be
- [00:05:56.719]where the embryo begins to develop
- [00:06:00.210]absorbing the Yolk and Albumin as its
- [00:06:03.596]source of nutrition. Essentially the food
- [00:06:06.624]and water as it grows and develops. But
- [00:06:09.485]if we were not to have eggs that came from
- [00:06:13.134]a farm to have hens and roosters and just
- [00:06:15.106]bought them from the grocery store they
- [00:06:17.030]would never hatch because they would be
- [00:06:19.256]without a Germinal Disc or Germ Spot so
- [00:06:21.752]they would have came from a farm that
- [00:06:23.574]just have hens. Now we'll place eggs in
- [00:06:27.837]the incubator for you to watch hatch
- [00:06:30.979]live at the 4-H Egg-Cam. Thank you!
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