Early life likely began a. in the atmosphere b. in the ocean c. on the Earth’s surface
All kinds of life are made of a. very similar chemicals b. very different chemicals c. an equal mix of similar and different chemicals
Life probably began when molecules bonded to form a. RNA b. DNA c. mRNA
Discussion/essay questions
The origin of life on Earth is one of humanity’s most important and controversial questions. Why do you think this is? Do you think religion and science have the same purpose?
Transcript
Abiogenesis is the process that causes non-living materials to become living things. Abiogenesis is one of the greatest mysteries in science. Early life likely began in a “chemical soup” in the ocean. Scientists have observed that all kinds of life are made of very similar chemicals. People, plants, animals, and bacteria all share a common ancestor, which lived about 4.2 billion years ago. Most scientists agree that life probably began when molecules in the chemical soup bonded to create RNA. RNA can cause the chemical reactions that made early life possible, and it can also store information. This allows it to replicate itself. Some scientists have tried to begin the process of RNA bonding in labs. However, no one has ever observed abiogenesis. Because all life is made of the same chemicals, many scientists believe that abiogenesis has only happened once on Earth.
A slime mold is most similar to a a. plant b. animal c. fungus
One interesting thing slime molds can do is a. convert light into nutrients b. camouflage with their surroundings c. store and communicate memories
When put in a maze modelled after Tokyo, the slime mold a. got lost because it had no memory of the space b. began to consume the walls of the maze c. recreated the Tokyo railway system
Discussion/essay questions
Slime molds are an example of an organism that shows intelligence without a brain. This has caused some scientists to rethink the definition of “intelligent life.” How would you define intelligence? Do you think we underestimate plants and fungi?
Transcript
A slime mold is a type of organism similar to a fungus. Slime molds grow in damp, dark environments. There are over 900 species. For a long time, scientists did not know how to classify slime molds. They behave like plants, animals, and bacteria in different ways. Slime molds are interesting because they can join together to form networks of cells. These networks can store and communicate memories. Slime molds are also very good at navigation. They use spatial memory to find the shortest path to their destination. In fact, in 2010, a group of researchers put a slime mold in a maze modelled after Tokyo. The researchers placed food at major hubs. The slime mold chose a path almost identical to Tokyo’s railway system. Since this test, scientists have experimented with using slime molds to optimize human transportation.
The biosphere is a. the surface of the Earth, where there is plenty of light and oxygen b. the areas of the Earth where most plants and animals live c. all of the areas on Earth that can sustain life
Microbes that can live in environments without much water, sunlight, or oxygen are called a. eukaryotes b. extremophiles c. eubacteria
The “shadow biosphere” hypothesis suggests that a. life on other planets is probably very similar to life on Earth b. new types of bacteria are evolving very quickly underground c. Earth may contain microbes that have very different chemical structures from us
Discussion/essay questions
Do you believe in life on other planets? Why or why not? Why do you think we haven’t found any?
Transcript
The biosphere is all of the areas on Earth that can sustain life. Most complex plants and animals need lots of water, oxygen, and sunlight to survive. When scientists look for life on other planets, they seek places that have the potential to provide these things. On Earth, however, certain microbes thrive in environments that are low in these essential ingredients. These microbes are called extremophiles. They live in volcanoes, deserts, and Antarctic ice. Some extremophiles survive because they can use unusual chemicals to sustain themselves. It is possible that Earth contains microbes with chemical structures that are very different from our own. This hypothesis is called the “shadow biosphere.” A shadow biosphere would be made up of life that is chemically unrelated to life as we know it. If this type of life exists, there may be more habitable planets than we think.
The process called “senescence” is when a. an animal’s cells stop reproducing b. an animal lives forever c. an animal reverses its life cycle
The only animal considered biologically immortal is a. the “immortal tortoise” b. the “immortal lobster” c. the “immortal jellyfish”
Scientists study slow-aging animals in case their cells can a. reveal information about the past b. help extend human lives c. bring extinct species back to life
Discussion/essay questions
Do you think it is possible for humans to reach biological immortality? Do you think it is a good idea? Why or why not?
Transcript
Biological immortality is a very rare phenomenon. Most species go through a process called senescence, which means the cells in their bodies stop reproducing over time. As these species get older, disease and death become much more likely. However, a few rare species do not experience senescence at all. Lobsters are one animal that does not age typically. They can repair their own DNA using a chemical called telomerase. Tortoises also appear to delay senescence. A species called the “immortal jellyfish” is the only animal believed to be truly biologically immortal. These jellyfish can still die, but not of old age. This is because they have the ability to reverse their aging process entirely. Scientists study these slow-aging species in case their cells can help extend human lives.
Circadian rhythms respond to changes in a. light b. temperature c. gravity
Melatonin is a hormone that helps with a. energy b. memory c. sleep
Some people struggle to fall asleep because a. their brains make too much melatonin b. their brains make melatonin later in the night c. their brains make melatonin too early in the day
See answers below
Discussion/essay questions
Do you think you get enough sleep? Why or why not? What are your sleeping habits?
Do you think it’s possible for society to accommodate for people with different sleeping patterns?
Transcript
A circadian rhythm is a natural clock that helps control our bodily processes. Humans’ circadian rhythms keep track of time by detecting changes in the light. When the sky becomes dark enough, the brain receives a signal to produce melatonin, a hormone that helps us fall asleep. However, not all circadian rhythms are the same, and some people’s brains do not produce sufficient melatonin until later in the night. People who naturally stay awake later often struggle with the work and school hours of modern society. Circadian rhythms can also be disrupted by unnatural light, such as the blue light that comes from screens. For this reason, many people report getting less sleep than they need.
The article says that many people have ethical concerns about the consequences of human cloning. What do you think some of those concerns might be?
Do you think human cloning should be legal? Why or why not?
Transcript
Cloning is the process of creating a genetically identical copy of an organism. Researchers have been experimenting with cloning since the 1900s, when they attempted to create genetic copies of animal embryos. As technology became more advanced, it became possible to make clones of fully-grown creatures. The first successful cloning of an adult organism was in 1996, when a British research group managed to produce a cloned sheep. The sheep’s name was Dolly, and she lived for six years. Scientists have since managed to clone many other types of animals. In fact, there are now companies that offer expensive pet cloning services. The idea of human cloning has come up in scientific discussions, but many people have ethical concerns about the consequences. Because of this, human cloning is illegal in several countries.
A stem cell is a type of cell that can divide into more specialised cells during reproduction. There are two different types of human stem cells: embryonic stem cells, which are found in the tissue of embryos, and adult stem cells, which are found in fully developed humans. The main difference is that embryonic stem cells can become any kind of cell, but stem cells can only become cells for certain types of tissue. In recent years, doctors and have become very interested in the medical uses of human stem cells. Stem cells could be used to treat illnesses such as , and regenerate tissue in organs that would otherwise require a transplant. Research has even shown that it is possible to genetically modify adult stem cells to like embryonic stem cells, which would make it much easier to grow any kind of tissue.
Comprehension questions
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Discussion/essay questions
Stem cell research is a bit of a controversial topic in some places. Why do you think there is so much debate about it?
Transcript
A stem cell is a basic type of cell that can divide into more specialized cells during reproduction. There are two different types of human stem cells: embryonic stem cells, which are found in the tissue of embryos, and adult stem cells, which are found in fully developed humans. The main difference is that embryonic stem cells can become any kind of cell, but adult stem cells can only become cells for certain types of tissue. In recent years, doctors and researchers have become very interested in the medical uses of human stem cells. Stem cells could be used to treat illnesses such as cancer, and regenerate tissue in organs that would otherwise require a transplant. Research has even shown that it is possible to genetically modify adult stem cells to behave like embryonic stem cells, which would make it much easier to grow any kind of tissue.
