Classification and The History Of Life Flashcards
How many species have biologist identified and named?
1.5 million
How many species do biologist think exist on earth?
8.7 million
Who developed the system known as bionomical nomenclature?
Carlos Linnaeus
What two names is a species full name made up of?
Their genius and species
What is a genus?
It is the “last name” of a species and means the two organisms with the same genus are closely related
What is a species name?
It is the most specific part of the name
What does the species name often describe?
An important trait
What are the rules for naming a species?
- genus then species
- Latin or Greek
- italicized in print
- capitalized genius, but not species
- underline when writing
What is classification?
The naming or arrangement of organisms into groups based on their similarities.
What is a taxa?
A group of organisms.
What does a taxonomist do?
They are scientist that identify and name species.
Who developed the first classification system?
Carlos Linnaeus
How many levels did the first classification system begin with, and how many are there now?
Was 4, now 7
If a word ends with idae what does it mean?
It is a family name
What are the taxa from highest to lowest in the classification system?
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
What are the two reasons why we need scientific names for species?
- there are a lot of organisms on earth
* every language has its own common names for species
What is the benefits of classifying?
- Helps to identify the relationship between organisms.
- Requires scientist to clearly identify key characteristics of each organism.
- Prevents misnomers (thinking a star fish is really a fish).
What is a dichotomous key used for?
Identifying organisms
How does a dichotomous key give characteristics?
In pairs
Define phylogeny?
It is the evolutionary history of lineages.
What is another name for a cladogram?
Cladistic analysis
Define cladogram.
A diagram showing how organisms are related based on shared, derived characteristics.
What do groups called clades share?
A single common ancestor and all descendants.
What is the difference between clades and taxa?
Clades can be monophyletic, where taxa can be monophyletic or paraphyletic.
Define monophyletic.
A group that includes a single ancestor and its descendants.
Define paraphyletic.
Includes common ancestor, but not all descendants.
What do nodes represent?
Common ancestors.
What does a root represent?
A common ancestor shared by all.
What are the 6 current kingdoms?
- Plante
- Animalia
- Protista
- Fungi
- Eubacteria
- Archae-bacteria
What two kingdoms was Monera divided into in the 1990’s?
- Eubacteria
* Archae-bacteria
What are the 3 domains?
- bacteria
- archaea
- eukarya
What are the characteristics of the species in the bacteria domain?
- prokaryotes
- cell walls with peptideoglycan (Gran+)
- unicellular
- can be heterotrophic or autotrophic
What are the characteristics of species in the domain archaea?
- no peptideoglycen (Gran-)
- contain a type of lipid only found in them
- live in extreme environments
What are the characteristics of species in the domain eukarya?
- cells contain membrane bound organelles
* contain protests, fungi, plants, and animals
What are the characteristics of Protists?
- eukaryotic organisms that can’t be classified as animals, plants, or fungi
- display great variety
- uni or multicellular
What are characteristics of fungi?
- heterotrophs
- feed on dead or decaying organic matter by secreting digestive enzymes into it and then absorbing it.
- can be multi or unicellular
Describe the characteristics of plants.
- multi cellular
- photosynthetic
- non-mobile
- have cell walls made of cellulose
What are the characteristics of Animalia?
- multicellular
- heterotrophic
- no cell walls
What are the types of fossils?
- permineralized
- natural casts/molds
- trace fossils
- preserved remains
- Amber preserved
Describe permineralized fossils.
Minerals carried by water and are deposited around hard structures.
Describe natural casts/molds.
Flowing water removed all original tissue, leaving a mold that is filled in with minerals.
Describe trace fossils.
Record the activity of organisms.
Describe preserved remains.
Found in ice or peat bogs.
Describe Amber preserved fossils.
Insects are preserved in tree resign.
Where do most fossils form?
In sedimentary rock.
What can paleontologisst infer from fossils?
- structure
- what they ate
- predators
- environment
What are the two ways to date fossils?
- relative dating
* radioactive dating
What is relative dating?
Aging determined based on placement of fossils.
What is radioactive dating?
Using radioactive isotopes to age fossils.
What is another name for rock layers?
Strata
What is an index fossil?
A fossil that is used to date other fossils.
What characteristics must an Index fossil have?
It must be short-lived and widespread.
Define half-life.
The amount of time it takes for half of a radioactive sample to decay.
How long of a half-life does carbon-14 have?
5730 years
What fossils is carbon-14 used to date?
Fossils younger than 60,000 years.
What radioactive isotopes are used to date fossils older than 60,000 years?
- potassium 40
- uranium 238
- rubidium 87
What period covers about 88% of the Earth’s history?
The Precambrian period
List the divisions of the geological timescale from largest to smallest.
Eons, eras, and periods.
Describe the nebula hypothesis.
There was a swirling mass of dust and debris. Small particles collide overtime to form earth. The elements slowly arrange themselves by density.
What allowed primitive earth to cool?
The formation of our atmosphere, and especially the presence of oxygen.
What effect did oxygen have on primitive earth?
- Iron in oceans rusted and sank to the bottom.
- The ozone layer formed.
- It led to the first mass extinction.
Describe Oparin’s contributions to the history of life.
He developed the primordial soup hypothesis about how the first organic molecules were formed.
Describe Miller and Urey’s contribution to the history of life.
They tested Oparin’s hypothesis and it was successful.
True or false
The results of Miller and Urey’s experiment were proven false.
True
What was Sydney Fox’s contribution to the history of life?
He suggested that proteinoid microspheres could have given rise to the first cells.
Why do scientists think that RNA evolved first?
- RNA helps DNA replicate
- it can replicate itself
- it can be a catalyst
Describe the changes that occurred in living things through the geological timescale.
Softbodied organisms, Cambrian explosion, land plants, flying insects, fish/sharks, vertebraes moved to land (amphibians), reptiles, dinosaurs, mammals (small), birds, mass extinction, mammals become large, ice age, evolution of man.
Describe Lynn Margulis’s theory.
Large prokaryotes engulfed smaller prokaryotes, but didn’t digest them. This led to the first eukaryotes.
Why is sexual reproduction important to evolution?
It allows for genetic diversity.
Why is the Pre-Cambrian time so incomplete?
There were only softbodied organisms, which almost never fossilize.
How old is earth?
4.6 billion years old
What did the original earth atmosphere contain?
Very deadly gases such as carbon dioxide and hydrogen cyanide; and water vapor.
What color was early Earth’s sky?
Pinkish orange
What color was early earth’s oceans?
Brown due to the presence of iron.
How long ago do scientist think the first living things formed?
200 to 300 million years ago
