Studied by 32 peopleThe current classification system used by biologists
has three domains; is updated and revised whenever new information becomes available; is used for all living organisms (plants, animals, bacteria, fungi, and protist)
Which of the following is the cause of the current extinction crisis?
Human activities that involve altering habitats, changes in sea levels, and changes in weather patterns on a global scale are causing mass extinctions.
Allopatric speciation occurs when
populations are geographically separated.
The Cretaceous extinction, which lead to the extinction of the dinosaurs, was most likely due to
an large asteroid hitting the earth.
Which of the 3 domains do animals belong to?
Domain Eukarya
The smallest or most specific level of biological classification is
species
_____________ is the loss of a species or taxonomic group from the planet.
Extinction
Areas of the planet that support the highest number of species are known as ___________. Examples include coral reefs and tropical rain forests.
biodiversity hotspots
Which of the following can lead to sympatric speciation?
habitat differentiation; sexual selection; polyploidy
According to the biological species concept, the western spotted skunk and the eastern spotted skunk are two distinct species. This means that the two species
they do not interbreed.
The ___________ is the most used method since it defines a species as being one that is reproductively isolated from other species. This model only works if a species reproduces sexually and is currently alive.
biological species concept
The __________separates species based on differences in physical traits, or morphology (morph- means "form"). This is useful for studying the fossil record where you can't determine reproductive isolation. It is difficult to apply to organisms that do not leave fossil records.
morphological species concept
The ____________ traces the evolutionary history of the organism and its relatedness to other species through its traits. In this model, the study of an organism's traits and location on the evolutionary tree is a better indication of whether it is a unique species that the biological species concept.
phylogenetic species concept
________ is the identification and naming of species.
Taxonomy
Species are identified by a two-part _____ name, such as Homo sapiens (humans) or Panthera orca (jaguar).
Latin
Scientists have attempted to ______ the total biodiversity on the planet.
estimate
One of those studies placed the total at around ____ million species, give or take ___ million. (This number does not include bacteria and viruses.)
8.7; 1.3
___________, refers to not only the total number of a species in an area, but also how many different species are found in that area.
Biodiversity
_________________ cover only 2.4% of the world's surface, but they account for over 50% of all plant and 42% of all animal species.
Biodiversity hotspots
An _______ is an individual of one species
organism
A ________ is a group of similar organisms that are reproductively compatible and capable of interbreeding and producing living offspring.
species
A _______ is a group of individuals of the same species living in the same area.
population
The biological species concept uses ______________ to designate separate species.
Reproductive isolation
___________ is the formation of new species
Speciation
_________ is when new species evolve rapidly after some event
Adaptive radiation
In the _________ model, small changes occur periodically in a population until reproductive isolation occurs. Charles Darwin was a supporter of the gradual pace of speciation.
gradualistic
____________________, periods of no change (equilibrium) are interrupted (punctuated) by events that promote rapid speciation.
punctuated equilibrium
When geographic separation leads to speciation it is known as _________ ________.
allopatric speciation
Speciation can also occur when individuals are not physically separated; Species may also become isolated by differences is preferred resources or different times of the year for mating.
sympatric speciation
Barriers that prevent a mating attempt between two species are known as __________________.
prezygotic isolating mechanisms
If the barrier occurs after mating and fertilization it is known as a ________________.
postzygotic isolating mechanisms
Which of the following is a prezygotic isolating mechanism?
Hybrid sterility
Speciation can occur...
rapidly; slowly; When species are geographically separated; When species are not geographically separated
The largest taxonomic group is a...
Domain
How many mass extinctions have occurred in Earth's history?
5
(True or False) Viruses are prokaryotic organisms
False
Which mode of prokaryote nutrition is similar to digestion in humans?
Chemoheterotroph
Which domains include prokaryotic organisms?
Domain Bacteria and Domain Archaea
Which of the following describes eukaryotic cells?
they have a nucleus; they have organelles; they have larger than prokaryotic cells
Protist belong to..
Domain Eukarya
Animals are part of the supergroup...
Opisthokonts
A mutualistic relationship
Benefits both species
Which fungi phylum makes mushrooms?
Basidiomycota
Which of the following does NOT describe protist?
They can be autotrophic or heterotrophic
The phylum Basidiomycota produces mushrooms where are the ___________ of the fungi.
Reproductive Structure
When plants evolved and moved onto land 500MYA which of the following would have been a challenge?
Gravity
The dominant generation in angiosperms is
Diploid (sporophyte)
Where does coal come from?
Dead plant material
Which group of plants evolved first?
Bryophytes
Fems have all of the following except
Seeds
During the age of the dinosaurs the main plant groups would have been...
Seedless vascular plants and gymnosperms
Fungi obtain nutrients through....
Absorption
In an experiment done with 2 species of cichlid fish, females were unable to recognize males of their own species under monochromatic light. This shows that females are choosing males based on color differences only. This is an example of...
Sexual selection
Sexual selection can lead to
The diversity of life is often portrayed as a tree to provide a simple visualization of evolutionary relationships
Tree of Life
Scientists refer to these trees as ________
phylogenetic trees
Currently, all organism fall into one of three domains..
Domain bacteria; Domain archaea; Domain eukaryotes
Doman bacteria and Domain archaea fall under the same category of...
Prokaryotes
The term ______ is used to refer to the loss of a species from the planet. The term also applies to any of the higher taxonomic groups.
extinction
In a _________, a large number of plant and animal species, from many different taxonomic categories, are lost in a relatively short period of time.
Mass extinctions
1st: Cretaceous-Tertiary: 80% Extinction Rate
Asteroid or comment impact; volcanic activity, climate change
2nd: Triassic: 75% Extinction Rate
Increases in greenhouse gases; rapid climate change
3rd: Permian: 95% Extinction Rate
Volcanic activity; increase in greenhouse gases, rapid climate change
4th: Devonian: 70% Extinction Rate
Asteroid impact; rapid climate change (global cooling)
5th: Ordovician: 85% Extinction Rate
Rapid climate change (global cooling); falling sea levels
______ refers to a single-celled organism that lacks a nucleus and internal membrane-bound organelles.
Prokaryote
Prokaryotes are commonly called _______, there are prokaryotes that are not true bacteria
bacteria
Prokaryote reproduce asexually by a process known as ______ ______.
binary fission
This results of binary fission are __________.
two identical cells
Prokaryotic cells have evolved to have almost every form of metabolism and have the _________ from a variety of different means
ability to obtain nutrients and energy
Photoautotrophs
Cells that use solar energy to manufacture their own food.
Photoheterotrophs
Cells that use the sun for energy, but also use organic materials as the building blocks of their food.
Chemoautotrophs
Cells that use other energy sources, such as hydrogen gas, to obtain the energy to manufacture their own food.
Chemoheterotrophs
Cells that use the breakdown of organic material to supply energy and the materials needed to manufacture food.
______________ experiments supported the idea that conditions on early earth could have led to the creation of organic molecules necessary for early life.
Miller-Urey
The oldest prokaryotes fossils date back ________.
3.5 MYA
First prokaryotes were ______
anaerobic
_________ prokaryotes evolved later and added oxygen to the atmosphere.
Photosynthetic
Bacteria are the ____________________________.
oldest organisms on the planet
Bacteria are classified based on...
shape, metabolic abilities, and similarities in their DNA
________ are a unique form of prokaryotes that have adapted to life in environments that are often hostile to other organisms, such as geysers and hot springs (extremophiles)
Archaean
We currently know of ___________ of archaeans
three different types
Thermophiles
tolerate environments with extreme heat and sulfur content.
Methanogens
live in oxygen-free environments such as swamps and the intestinal tracks of livestock.
Halophiles
survive in high-salt habitats, such as the Dead Sea or Great Salt Lake.
All _______ are eukaryotes
protists
All protists posses
a nucleus containing DNA; membrane-bound organelles, such as mitochondria and endomembrane system
Protists can be....
Single-celled; Form colonies; Multicellular structures (like algae)
Protists are single cells, or collections of cells, that __________ associated with other eukaryotic organisms
do not form the tissues
All protists can be ________ or _______ or _____
autotrophic; heterotrophic; both
First protists evolved from the prokaryotes toward the end of the _________ ______ about 800 million to 1 billion years ago
Precambrian period
Protists were placed into a single kingdom, called _______ ______, as single-celled eukaryotes.
Kingdom Protista
Divisions within the protists were typically assigned based on whether the organisms were.....
autotrophs; heterotrophs; saprophytic (feed on dead or decaying material).
Protist are now organized into ________
Supergroups
it is unlikely that all protist share a _________________.
common evolutionary history.
Some protists are more _______, others are more like fungi or animal-like
plant-like; animal-like
Examples of supergroup: Excavata are
euglenozoans
Examples of supergroup: Chromalveolata are
dinoflagellates, gold and brown algae, sporozoans
Examples of supergroup: Rhizaria are
foraminiferas
Examples of supergroup: Archaeplastida are
red and green algae, land plants
Note
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