Unit 7 Flashcards
What are the 6 possible places we hope to find evidence of life in our solar system (other than Earth?
2 satellites on Jupiter: Ganymede and Europa.
2 satellites on Saturn: Enceladus and Titan. MAYBE Venus? is there 6?
What do we think life requires to develop?
LIQUID WATER
Why does living matter need energy?
Living matter utilizes energy from its environment to survive and create offspring
What is the simplest life form we are aware of?
Bacteria
Is a virus a life form? Why or why not?
No, because they can live without host cells
What is the role of DNA? RNA?
DNA: Carries the genetic information of all organisms, primary role is to contribute the information required for production to regulate chemical reactions in cells. RNA: Carries out the coded instructions given by DNA
Why is life on Earth (and probably elsewhere) carbon based instead of silicon based?
Carbon atom bonds to other atoms, can form long, complex, stable chains that are capable of extracting, storing, and utilizing energy. Silicon forms weaker bonds with itself than carbon does
Describe how the process of natural selection results in the evolution of species. What was the miller-Urey experiment? What did they create (and how)? What was the significance?
Each time an organism reproduces, its offspring receive the data stored in the DNA, but some variation is possible. Creatures that are unfit die. Natural selection is merciless to theindividual, but it gives thespeciesthe best possible chance to survive in a changing environment. The experiment was designed to find out how lightning - reproduced by repeated electric discharges - might have affected the primitive Earth atmosphere. It created the building blocks (amino acids) of cells
What evidence of life has been found (or claimed to have been found) in meteorites?
Found to contain a wide variety of organic compounds, including many amino acids.
How/where might have amino acids linked together to form larger molecules?
Complex molecules probably took advantage of the energy of hot-springs well away from surface conditions, which meansthese processes had no dependence on sunlight
How old are Earth’s oldest fossils?
The most ancient fossils found to-date are about 3.5 billion years old
Stromatolites, some of the earliest complex organisms, produced oxygen which was toxic
to them – how did they survive? Is this process still happening today?
??
What is the difference between a prokaryote and a eukaryote?
Prokaryotes are simple, single-celled organisms, lacking structures like a nucleus, the reproduce ASEXUALLY. Eukaryotes have larger, more organized cells and live by respiration, meaning they use oxygen for energy, and are also sexual.
Why do we need ozone? How did life survive before there was enough oxygen in the atmosphere to create ozone?
With no oxygen in the atmosphere, there would have been no ozone, and no ozone layer to shield Earth’s surface from harmful ultraviolet radiation. Ultraviolet radiation breaks down amino acids, and so attacks the building blocks of life
What is the Cambrian explosion and when did it happen?
Half a billion years ago, perhaps a change in Earth’s climate, and life exploded into a wide diversity of complex forms
