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Reproduction, Migration and Basic Needs

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Subido el 28 de mayo de 2007 por EducaMadrid

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In the second segment of the Case of the Zany Animal Antics, the tree house detectives learn about animals' basic needs, the food chain, reproduction and why animals migrate.

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So what's up? What kinds of animals will Jacob find in his backyard? 00:00:00
Will the treehouse detectives find a new species? 00:00:05
Is a backyard nature preserve a good idea? 00:00:08
Find out in the next exciting chapter of The Case of the Zany Animal Antics. 00:00:11
Be sure to look for the answers to the following questions. 00:00:16
What are the basic needs of animals? 00:00:20
What are the three basic reasons animals migrate? 00:00:22
What is different between mitosis and meiosis? 00:00:25
Why is it important for a species to have genetic diversity? 00:00:28
You're not going to believe it, but it's all right here. 00:00:35
With proper planning and maintenance, you can create your own backyard preserve or habitat. 00:00:38
That's amazing. 00:00:42
And if you follow their guidelines, you can actually have your backyard officially recognized. 00:00:44
How'd you find out about all this? 00:00:48
I have a friend who deals strictly with agricultural stocks. 00:00:51
I gave him a few leads on some farm equipment companies, and he gave me the scoop on backyard habitats. 00:00:54
Cool. 00:00:58
So is everybody helping out? 00:01:00
All the treehouse detectives are pitching in. 00:01:02
Catherine and Bianca are down at NASA Kennedy in Florida, 00:01:04
and RJ is at Adventure Camp at Bush Gardens in Tampa. 00:01:07
You certainly have a great team. 00:01:10
Well, we haven't officially heard from RJ yet, but Dr. D is going to talk to him down in Florida. 00:01:12
And of course, NASA is a big resource. 00:01:17
Yes, they are. 00:01:19
In fact, Catherine and Bianca are supposed to talk to Mr. Mario Mota there today. 00:01:20
I hope they remember to download their get-up-and-go sheets. 00:01:24
You can download your own get-up-and-go sheet at the NASA SciFiles website. 00:01:27
Ms. Smith was right. 00:01:34
Mr. Mario Mota agreed to meet with us about animals. 00:01:36
He's a wildlife biologist working with sea turtles here at NASA Kennedy Space Center. 00:01:39
We hope to learn more about basic needs of animals, 00:01:43
and if we're lucky, we may find a sea turtle nest on the beach. 00:01:45
Well, an animal's basic needs are pretty simple. 00:01:48
They need food, water, shelter, and another mate so they can reproduce. 00:01:51
That sounds simple enough. 00:01:55
But how do you know what kind of food animals need? 00:01:57
It depends on the species, but no matter what kind of animal it is, 00:02:00
you've got to make sure you have a healthy food chain. 00:02:03
Do you know about the food chain? 00:02:05
We've studied the food chain in school. 00:02:07
It's the process of energy being transferred from one organism to another. 00:02:09
That's right. All living things need food for energy. 00:02:13
Producers such as plants, algae, and other organisms 00:02:16
convert light energy into sugar molecules that the plant uses for food energy. 00:02:19
A portion of this energy is passed on when animals called consumers eat the plants. 00:02:25
And then other consumers eat the consumers that ate the plants. 00:02:31
Very good. 00:02:34
And then energy stored in the molecules of one organism is transferred to another organism. 00:02:35
Making a food chain. 00:02:40
Plants are at the bottom. 00:02:42
Animals such as deer and rabbits are called herbivores and they eat the plants. 00:02:44
The herbivores are then eaten by a carnivore such as a wolf or lion. 00:02:49
Aren't there some that eat both plants and animals? 00:02:53
Yes, they're called omnivores. 00:02:56
In the final stage of the food chain, when an animal or plant dies, 00:02:58
they're broken down by bacteria called decomposers. 00:03:02
Decomposers turn the remains into materials that can be used by the plants. 00:03:05
The food chain seems simple at first, but they're really complex. 00:03:10
In a habitat, there are many feeding relationships. 00:03:14
Some can be very complex, so scientists use a food web to better share these relationships. 00:03:17
A web like a spider's web? 00:03:22
Actually, a spider's web is a good analogy. 00:03:24
It is intricately woven and connected just like a food web. 00:03:26
What if something happened to an animal's habitat? 00:03:29
The food web would be disrupted 00:03:32
and it could disrupt the balance of plant and animal populations. 00:03:34
What do you mean? 00:03:37
Let's say a fire destroyed a habitat and removed all the plants. 00:03:38
Without plants, then the herbivores would not have food to eat. 00:03:42
Without herbivores, then the carnivores would also starve. 00:03:46
The animals would have to move to a new habitat. 00:03:50
It's not always that easy. 00:03:53
Some habitats are small or enclosed by human development such as subdivisions, 00:03:55
making it difficult for animals to migrate to a new habitat. 00:04:00
If they can't find a new habitat, won't they die? 00:04:04
They might, and it could even lead to the extinction of some species. 00:04:07
I never realized that everything is so connected. 00:04:11
Yes, it is, and as part of my job here at NASA, 00:04:14
I study the sea turtles that live in the estuaries and lagoons 00:04:17
to make sure that their habitats aren't disrupted. 00:04:20
Mr. Mota told us all about how sea turtles are endangered and threatened 00:04:24
and how the beaches of NASA Kennedy provide nesting sites for them. 00:04:28
By monitoring their population health, age structure, growth reproduction, 00:04:31
mortality, and the impact of human activity, NASA can help the species thrive. 00:04:35
We didn't get to see any, but Mr. Mota said that to do that, 00:04:39
we would have to go out to sea. 00:04:42
I never knew that working as a zookeeper required so much. 00:04:48
Feeding, raking, cleaning, more feeding. 00:04:52
It's hard work, but it's very rewarding. 00:04:55
Of course, I'm looking forward to my break. 00:04:58
Hopefully, I can take care of a little research for the treehouse detectives 00:05:00
when I meet Dr. D today. 00:05:03
I'm the Busch Gardens Serengeti Plain habitat. 00:05:05
Each zebra has a unique set of stripes, 00:05:08
which creates an optical illusion that confuses a predator. 00:05:10
Oh, and I also learned that in 12 months, 00:05:13
the animals of the Serengeti Plain in Africa 00:05:15
will travel in a large circle of about 1,000 kilometers. 00:05:17
That's right. 00:05:21
The migration includes hundreds of thousands of herbivores, 00:05:22
including Thompson's gazelles, zebras, and wildebeest like these here. 00:05:25
Wow, they're pretty funny-looking animals. 00:05:29
African legend says they're made for spare parts. 00:05:32
Wildebeest are, however, well-suited for their migration. 00:05:35
For example, most wildebeest calves can stand and run 00:05:38
in less than 10 minutes after birth. 00:05:41
Wow, that's amazing. 00:05:43
But I thought migration meant going south for the winter. 00:05:45
Does it get that cold in Africa? 00:05:48
No, but there are seasons, wet and dry. 00:05:50
During the dry season, the grass dries out and water becomes scarce. 00:05:53
The herbivores that migrate leave in search of new grass and plentiful water. 00:05:56
I know that other animals, like birds, will migrate great distances. 00:06:01
Is this also in search of food? 00:06:05
There are three basic reasons for migration. 00:06:07
The first is food and water. 00:06:09
The second is to escape harsh weather. 00:06:10
So I guess that when birds fly south for the winter, 00:06:12
they get both a milder climate and more food. 00:06:15
Very good. 00:06:17
When they go north for the summer, 00:06:18
they get more hours of daylight to gather food. 00:06:20
How do animals travel thousands of kilometers to find their destination? 00:06:22
They must have some way to navigate. 00:06:26
Are you ready to try an experiment? 00:06:28
Okay, why not? 00:06:30
Close your eyes and I'll spin you around. 00:06:31
Now, keep your eyes closed and point north. 00:06:37
Are you kidding, Dr. D? 00:06:41
I can't point north with my eyes closed. 00:06:43
I'm not even sure if I can point north with my eyes open without a compass. 00:06:45
Some animals can. 00:06:49
They have a built-in compass in their head that helps them find their destination. 00:06:51
Other animals use the sun or stars to find their way. 00:06:54
Do other animals just use landmarks such as mountains or lakes on their journeys? 00:06:57
Sometimes they do. 00:07:01
Salmon migrate using a keen sense of smell. 00:07:02
Dr. D, can I ask just one more quick question? 00:07:05
Sure, RJ. 00:07:09
Can I open my eyes now? 00:07:11
Of course. 00:07:13
You'll need to see to feed the giraffes. 00:07:14
Dr. D, didn't you say there are three reasons for migration? 00:07:28
Good memory, RJ. 00:07:31
The third reason for animal migration is reproduction. 00:07:33
They want to provide their young with plenty of food 00:07:36
and with protection from predators and extremes in the environment. 00:07:39
I should have guessed reproduction. 00:07:42
That's one of an animal's basic needs. 00:07:44
And migration is all about meeting basic needs. 00:07:46
Thanks, Dr. D. 00:07:49
I'm working at the Nairobi field station later today. 00:07:51
That would be a great place to learn more about animal reproduction. 00:07:53
Right. 00:07:56
But first, let's get some more hibiscus leaves for the giraffe. 00:07:57
I've been going over our notes so far, 00:08:03
and I thank Jacobson for a big surprise. 00:08:05
There's a lot to consider when it comes to creating your own preserve. 00:08:07
Right. 00:08:10
Like whether your property is rural, suburban, or urban, 00:08:11
and what types of wildlife the habitat will support. 00:08:13
And, of course, you have to support the basic needs of the animals in your habitat. 00:08:16
Otherwise, they might migrate to another area. 00:08:19
Good thing we have RJ's notes on migration. 00:08:21
And Dr. D. talked about animal growth through reproduction. 00:08:23
Which is critical to the population. 00:08:26
Hopefully, RJ will learn more at the Nairobi field station at Bush Gardens in Tampa. 00:08:28
He's working with Ms. Deidre as we speak. 00:08:31
We should visit Jacob's backyard to see what types of animals already live there. 00:08:33
Good idea. 00:08:37
Otherwise, I'll have to hire some survey consultants as well. 00:08:39
What do you mean? 00:08:42
Well, if the habitat is successful, 00:08:44
I have other problems to consider. 00:08:46
Parking, ticket prices, a possible trios detective gift shop. 00:08:48
I'm sure you'll be giving Jacob some of the proceeds. 00:08:52
Don't worry. He's salaried. 00:08:55
Dr. D. mentioned that animal reproduction was important for the survival of species. 00:08:57
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This actually contains DNA. 00:09:54
Now DNA is a genetic code that determines the characteristics of animals, such as blonde hair, or brown hair 00:09:57
or blue eyes or green eyes. And so on as with humans. 00:10:03
So how does cells reproduce? 00:10:07
All cells reproduce from other cells. 00:10:09
Do all cells reproduce the same way? 00:10:11
No, there are actually two ways that cells reproduce. 00:10:13
One way that cells, such as body cells reproduce is through mitosis. 00:10:16
In mitosis, the cell duplicates its genetic material and then splits in two, forming two identical cells. 00:10:20
Mitosis is the process by which animals are able to grow. 00:10:26
Okay, so if that's mitosis, what's the other way? 00:10:30
Meiosis. 00:10:34
In this method, certain cells in the reproductive tissue divide so that they contain exactly half of the genetic material. 00:10:35
The chromosomes that carry the genetic codes occur in pairs. 00:10:41
And during meiosis, one half of each pair goes to the new cells. 00:10:45
In males, these are the sperm cells. 00:10:49
And in females, they're the egg cells. 00:10:51
Okay, so what does cell division have to do with reproduction? 00:10:53
In asexual reproduction, an offspring is formed from one parent cell. 00:10:57
The parent cell goes through mitosis and forms an offspring that is identical to the parent. 00:11:02
What types of animals reproduce asexually? 00:11:07
Flatworms and sponges are two of them. 00:11:09
Starfish, also known as sea stars, reproduce by regeneration, which is a form of asexual reproduction. 00:11:12
Right. 00:11:18
My dad said that if a starfish loses one of its rays, then it'll grow a new one. 00:11:19
And the one that broke off will grow four more. 00:11:23
That's right. 00:11:25
Long ago, some fishermen had a problem with starfish getting caught in their nets. 00:11:26
So they tried to get rid of them by chopping them into pieces. 00:11:30
But they were actually only adding to the problem because each new piece grew new limbs and created more starfish. 00:11:33
It sounds like they could have used a scientific method and done more research before they tried to solve the problem. 00:11:40
So what is sexual reproduction? 00:11:46
Well, it occurs when a sperm and egg cell combine to produce a new cell, which is called a zygote, which will then grow into an offspring. 00:11:48
Now, the offspring produced will receive a combination of genetic material from both the male and female parent. 00:11:55
Is one type of reproduction better than the other? 00:12:01
No, it just depends on the animal. 00:12:04
However, with sexual reproduction, meiosis helps to sort of shuffle the genetic material to the offspring to help ensure genetic diversity. 00:12:06
Why is that important? 00:12:14
Well, genetic diversity is critical for a species' survival because it increases the probability that only healthy, strong individuals will be produced. 00:12:16
Additionally, genetic diversity also helps reduce the probability that a genetic defect will overcome a population. 00:12:24
So would it be important to have a large population of a species for better genetic shuffling? 00:12:31
Yes. With a large population, there's much more genetic diversity. 00:12:37
Are there any factors that keep animals from reproducing? 00:12:40
Sure there are. Geographic isolation, genetic defects, and a lack of food, water, and shelter. 00:12:43
So for reproduction, it's pretty important to make sure that an animal's basic needs are met. 00:12:49
Yes, it is. Without adequate amounts of food, water, and shelter, animals will actually stop reproducing so that they can better enable those that are living to survive. 00:12:53
I can't wait to send my report to the treehouse detectives. 00:13:02
Maybe you can email them after we clean the porcupine habitat. 00:13:05
Well, a zookeeper's job is never done. 00:13:08
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Idioma/s:
en
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Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
686
Fecha:
28 de mayo de 2007 - 15:34
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
13′ 14″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
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480x360 píxeles
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79.34 MBytes

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