Chapter 15 Exam 2 Flashcards
Earth was formed about ____ years ago
4.6 billion years ago
Having cells that lack true nuclei
Prokaryotes
Prokaryotes evolved by about
3.5 billion years
Prokaryotes began oxygen production about 2.7 billion years ago as a result of ______ by _____ prokaryotes
Photosynthesis ; autotrophic
Composed of one or more cells that contain nuclei anf many other membrane bound organelles absent in prokaryotic cells
Eukaryotes
Eukaryotes first evolved from the
Prokaryotic community
A host cell containing even smaller prokaryotes
Prokaryotic community
Descendants of smaller prokaryotes
Mitochondria
Are descendants of smaller prokaryotes of plants and algae
Chloroplasts
Multicellular eukaryotes first evolved at least
1.2 billion years ago
About 540 million years ago, resulted in the evolution of all major animal body plans and all major groups
Cambrian explosion
About ____ years ago plants, fungi, and insects began to colonize the land
500 million
____ years ago, flowering plants, birds, and even mammals, including primates, began to dominate the landscape and this is when
65 million years ago and this is when dinosaurs went extinct
The origin of humans occurred
195,000
The earth of 4 billion years was still a
Violent turmoil
Volcanic eruptions belched gases into the atmosphere such as
Carbon dioxide
Methane
Ammonia
Other nitrogen compounds
Life comes from the interaction of
Chemicals and molecules
To learn how life originated from non living substances, biologists draw on research from the fields of
Chemistry
Geology
Physics
The structures and functions of life depend on more complex organic molecules such as
Sugars
Fatty acid
Amino acid
Nucleotides
I’m 1953, ____ devised an apparatus to stimulate conditions thought to prevail on early earth
Stanley Miller
Prokaryotes are
Unicellular
Scientists are testing other hypothesis for the organic molecules on earth including the hypothesis that life may have begun in
Submerged volcanoes or deep sea hydrothermal vents
Scientists are testing other hypothesis for the organic molecules on earth including the hypothesis that life may have begun in
Meteorites were the sources of Earth’s first organic molecules
The community of microorganisms that live in our bodies which help to supply vitamins, extract nutrition from food, decompose dead skin cells, guard against disease causing intruders
Microbiota
Prokaryotes also form our
Microbiota
Help decompose dead organisms and other waste materials returning vital chemical elemental such as nitrogen to the environment
Prokaryotes
Lack a membrane enclose nucleus
Prokaryotic cells
Lack other membrane enclose organelles
Prokaryotic
Typically have cell walls exterior to their plasma membranes and display range of diversity
Prokaryotic
Three most common shapes of prokaryotes
Cocci
Bacilli
Spiral
In many natural environments, prokaryotes attach to surfaces in a highly organized colony
Biofilm
May consist of one or several species of prokaryotes
Biofilm
May include protists and fungi
Biofilm
Can show a division of labor and defense against invaders
Biofilm
Prokaryotics can form on almost any type of surface including
Rocks
Metal
Plastic
Organic material including teeth
Many prokaryotes can reproduce by dividing in half by
Binary fission
Many prokaryotes can reproduce at ____ if conditions are favorable
At very high rates
Environments are usually limiting in resources such as
Food and space
Also produce metabolic waste products that may eventually pollute the colony’s environment
Prokaryotes
The metabolic talents of prokaryotes make them excellent symbolic partners with
Animals
Plants
Fungi
a close association between organisms of 2 or more species
Symbiosis
“Living together”
Symbiosis
Prokaryotes can also promote the breakdown of
Organic waste and dead organisms
The use of organisms to remove pollutants from water, air, or soil
Bioremediation
The use of prokaryotic decomposers to treat our sewage
Bioremediation
Has become an important tool for cleaning up toxic chemicals released into the soil and water by industrial processes
Bioremediation
Naturally occurring prokaryotes capable of degrading pollutants such as
Oil
Solvents
Pesticides
Naturally occurring prokaryotes capable of degrading pollutants such as oil, solvents, and pesticides are often present in
Contaminated soil
By comparing diverse prokaryotes at the molecular level, biologists have identified two major branches of prokaryotic evolution called
Bacteria and archaea
Life is organized into three domains
Bacteria
Archaea
Eukarya
Abundant in many habitats including places where few other organisms can survive
Archaea
One group of archaea live in very hot water
Thermophiles
One group of archaea thrives in such environments such as
Utah’s Great Salt Lake
Dead Sea
Seawater evaporating ponds used to produce salt
Halophiles
“Salt lovers”
Halophiles
One group of archaea live in anaerobic (oxygen free) environments and give off methane as a waste product
Methanogens
Abundant in the mud at the bottom of lakes and swamps
Methanogens
Many municipalities collect this methane and use it as a source of energy
Methanogens
Great numbers of methanogens also inhabit the digestive tracts of animals
Methanogens
Bacteria and other organisms that cause disease
Pathogens
Most pathogenic bacteria cause disease by producing
Poison
Proteins that bacterial cells secrete into their environment
Exotoxins
Exotoxins are proteins that bacterial cells ___ into their environment
Secrete
Chemical components of the outer membrane of certain bacteria
Endotoxins
Generally the most effective way to prevent bacterial disease
Sanitation
Researchers speculate that in some aspects of food processing might be involved in our
Intestinal microbes
___ of an obese person would increase the amount of body fat in mice
Intestinal microbiota
The fossil record indicated that the first eukaryotes evolved from prokaryotes around
2 billion years ago
These primal eukaryotes were ancestral to all other eukaryotes
Plants
Fungi
Animals
A common inhabitants of pond water can change its mode of nutrition, depending on availability of light and nutrients
Euglena
This protists is capable of photosynthesis and heterotrophy
Mixtrophs
Protists that live primarily by ingesting food
Protozoans
Protozoans with flagella
Flagellates
Typically living nonparasitic but some are nasty parasites such as Giardia, a common westborne parasite that causes severe diaherria
Protozoans with flagellates
Great flexibility in their body shape
Amoebas
The absence of permanent organelles for locomotion
Amoebas
Most species move and feed by means of ____, temporary extensions of the cell
Pseudopodia
Other Protozoans with pseudopodia include ___, which have shells
Forams
Provide movement of the protist and sweep food into the protist’s mouth
Ciliates (cilia)
hair like
Mostly freelivinh (nonparasitic) such as the freshwater ciliate
Paramecium
Includes heterotrophs and mixtrophs
Paramecium
Named for their grass green chloroplasts
Green algae
A hollow ball of flagellated cells that are very similar to certain unicellular green algae
Volvox