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the hypothesis of Panspermia proposes that meteors or cosmic dust may have brought ____ to Earth


All living organisms on Earth are characterized by cellular organization, growth, reproduction, and ____

heredity (sensitivity, regulation, homeostasis)

In Oparin's bubble theory, the chemical-concentrating bubble-like structures were called ____.

protobionts (microspheres, protocells, micelles, liposomes, or coacervates)

Organelles such as the nucleus are not present in ______organisms


Prokaryotes were the onloy organisms for about __billion years after life began on Earth


The early atmospheric condition of primitive Earth was thought to contain ample hydrogen atoms which was conductive to bond formation and is referred to as a(n) ________.

reducing atmosphere

________ are bacteria trhat are able to grow "without air" or that are poisoned by oxygen.


Endosymbiotic baceris relationships evolved into more complex cell types called ______, which possessed nuclear membranes and membrane-bound


Most recwent molecular studies have led to the addition of a sixth kingdom, Archae, containing certain groups or _____ with unusual cell walls, membranes and eukaryote-like genetic mechanisms


Through reconstruction of the conditions of the primitive Earth in simulation experiments, scientists have concluded that certain key ______ of life could have been created as a by-product of its conditions at birth.


Eukaryotic, mostly univellular (few multicellulaar), potosynthetic or heterotrophic, such as amoebas and algae, are callified into a kingdom called ____


Thomas Cech coined the term _____ to describe RNA molecules that behaved like enzymes


Oparin suggests the theory of:

primary abiogenesis

When phospholipid molecules are placed into water, microspheres form spontaneously. These microspheres are called:


Early cyanobacteria evolved a form of photosynthesis that permanently changed the Earth's atmosphere by releasing:


The only "origin of life on Earth" theory or possibility that permits testable scientific hypothesis is:

spontaneous origin

Spontaneous origin proponents hypothesize that life evolved from inanimate matter. According to this view, the force leading to life was:


The age of the Earth according to modern estimations is:

4.5 billion years

The oldest microfossils are of:


Life apparently originated on earth about:

3.5 billion years ago

According to geochemists which of the following would have been the most unlikely condition on the primitive Earth?

high levels of oxygen

It is generally agreed that the early Earth's reducing atmosphere contained;

Carbond dioxide, methane, nitrogen gas, hydrogen sulfide, water, and ammonia

Scientists beliebe that our atmosphere hav progressively changed as some living organisms began to harness sunlight energy to split water moleculesto form complex carbon molecules. This activity led to a increase in:


The first step in the origin of live is thougfht to be the formation of organic compoounds from atmospheric compentsnts, using all of the following forms of energy:

lightning, radioactive decay, solar radiation, and volcanic eruption

Among the products of the Miller-Urey experiments and subsequent experiements by others, it was shows that shich of hte following could be produced in simulated primitive Earth conditions?

amino acids, adenine, and other nucleotides

Oparin, in his theory of "primary abiogenesis" suggested cell predecessors of:


It was recently discovered that enzyme-like catalysis can be carrie dout not only bey enzymes but also by:


The most primitive bacteris that exist today are:


Bacteria that lack the peptidoglycan in their cell walls are


The first engergy for the first photosynthetic cells was:


Oxygen increased from 1% to 21% because of the photosynthetic activity of:


The oldest fossils of eukaryotes have been estimated to be:

1.5 billion years old

multicellularity and endosymbiotic relationship is not observed in:


Recent molecular studies have added a new 6th kingdom for prokaryotes that lack peptidoglycan in their cell walls. It is callsed:

archaebacteria kingdome

theory that meteors and /or cosmic dust clouds carried various primitive life forms to the Earth, which eventually evolved into what we know today.


what primitive condition was needed for the formation of amino acids, and so the formation of complex carbon molecules common to life?

reducing atmosphere

the theory that the organic molecules formed in the soupy mixture of ancient oceans had to find some form of protection, or become disassociated again and again, and thus, bubble formation offered some forms of protection

bubble theory

archaebacteris are considered the most primtive life forms on Earth, but still utulize ____as their energy-carrying molecule


What do eukaryotes all have in common?

membrane-bound nucleus

diversity among the vast amound of organisms have arisen on earth due to: (4)

seual reproduction, multicellularity, a membrane-bound nucleus, and endoplasmic reticulum

Experiment showed that organic molecules important to life could have been formed from a vast array of simple chemicals


Archaebacteria do not have_______ in their cell wall, which bacterida do have


archaebacteria are mostly likely to be found today in: (2)

hot sulfer springs and in the Dead Sea

names of early environmentally isolated, chemical concentrating structures


cellular organelle containing organisms; include all organisms except bacteria


blue-green algae; a type of bacteria important in the history of life on earth


most primmitive bacteris that exists today; methane producing bacteria; abscense of peptidoglycan cell-wall


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