Exam questions Flashcards
Give a brief history about life on earth.
Life on Earth began about 3.5 to 4 billion years ago. The first life forms were single-celled organisms similar to bacteria. Eukaryotes appeared 2 billion years ago. The first multicellular organisms did not appear until about 610 million years ago. Many different types of organisms evolved during the next ten million years, in an event called the Cambrian Explosion. Plants and fungi did not appear until roughly 500 million years ago. They were soon followed by arthropods (insects and spiders). Next came the amphibians about 300 million years ago, followed by mammals around 200 million years ago and birds around 150 million years ago.
What does the eukaryotic and prokaryotic cells look like? What are their main structures?
PROKARYOTIC: It has ribosomes, the cytoplasm, plasmids and a nucleoid inside. It has a cell wall and on the outside hair-like pili and a flagellum.
EUKARYOTIC: Cytoplasm, Mitochondria, ribosomes, nucleus, cell wall, Golgi apparatus, lysosome, endoplasmic reticulum
How was the earth formed?
The formation of the sun consumed more than 99 percent of the matter in the nebula. The remaining material began to coalesce into various masses. The cloud was still spinning, and clumps of matter continued to collide with others. Eventually, some of those clusters of matter grew large enough to maintain their own gravitational pull, which shaped them into the planets and dwarf planets that make up our solar system today.
What is a biomarker? Some examples?
A biomarker can be any kind of molecule indicating the existence, past or present, of living organisms. Microbes emit methane and nitrous oxide into the atmosphere, and seaweeds emit chloromethane gas
What is astrobiology?
Astrobiology is the study of the origin, evolution, distribution and future of
life in the whole Universe
How was astrobiology established as a science?
By demonstrating its value to understand life on Earth
and its evolution
By demonstrating how we can understand the evolution of the Solar System and Earth itself
By demonstrating how it can help to predict the future evolution of the Solar System and life in it
By clarifying, eventually, one of the great questions: Are we alone in the Universe?
