Chapter 20 Flashcards
Study of evolutionary relationships. The evolutionary history of a species or group of related species. The evolutionary history and relationship of an organism or a group of organisms it may have evolved, or to which species it is most closely related. Provide information on shared ancestry but not necessarily on how organisms are similar or different.
Phylogeny
How we classify organisms or put them into groups. Classifies organisms and determines their evolutionary relationship.
ex.) data from fossils, body part structures, molecules from organisms, and DNA analysis.
Systematics
Is the ordered division and naming of organisms. Science of naming and dividing organisms. “arranged law.” Th science of classifying organisms to construct internationally shared classification systems with each organism placed into increasingly more indusive grouping.
Ex.) grocery store organization. On large space is divided into departments, then each department further divides into isles, then each aisle into categories and brands, and then finally into a single product.
taxonomy
The two-part scientific name of a species is called a what? How scientists refer to an organism by its genus and species.
binomial
What are the three options of domains in a hierarchical classification system?
Domain: Eukarya, Bacteria, and Archaea
What is the correct order of the taxonomic groups of hierarchical classification system?
What are the names at each level known as?
Domain –> Kingdom–> Phylum–> Class–> Order–> Family –> Species
( Do Kids Prefer Candy Over Fresh Green Spinach)
-Taxons
Systematics depict evolutionary relationships in branching these. Show the evolutionary pathways and connections among organisms. A diagram used to reflect evolutionary relationships among organisms or groups of organisms. “tree of life” to illustrate when different organisms evolved and to show the relationship among different organisms. These will continue to change as researchers discover new types of life and learn new info.
phylogenetic trees
Phenotypic and genetic similarities due too ancestry. Organisms with similar morphologies or DNA sequences are likely to be more closely related. Features that overlap morphologically (in form) and genetically as this. Stem from developmental similarities that are based on evolution.
ex.) bones in bats and bid wings have these.
More grouped bones arranged in a similar way. The more complex, the more likely an overlap due to common evolutionary past.
Homologies
These are determined based on the degree of similarity in nucleotide sequence between taxa
Homologies
When similar characteristics occur because of environmental constraints and not due to a close evolutionary relationship.
ex.) insects use wings to fly like bats and birds, but the wing structure and embryonic origin is completely different. the bird and bat wings are homologous because the bones are inherited from a common ancestor, while the wings themselves are these as they evolve independently.
analogous (homoplasy)
Homologous and Analogous.
- Homologous: shared by similar embryonic origin.
- Analogous: have a similar function
ex.) the bones in a whale’s front flipper are homologous to the bones in the human arm. These structures are not analogous. A butterfly or bird’s wings are analogous but not homologous.
Limitations of Phylogenetic Trees:
- It is possible for the 2 groups to appear more different than the other groups that are not closely related.
- Only show the order in which things took place. Branches do not account for length of time, only evolutionary order
- New branches from a tree form.. groups that are not closely related, but evolve under similar conditions, may appear more phenotypically similar to each other than to close relative
Occurs when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineages.
Convergent Evolution
After scientists sort the homologous and analogous traits, they often organize the homologous traits using this. Classifies organisms by common descent.
Cladistics
A group of species that includes an ancestral species and all its descendants. Groups of organisms that descended from a single ancestor.
Clade
A characteristic found in the ancestor of a group. All of the organisms in the taxon or clade have that trait. A character that originated in an ancestor of the taxon.
Shared ancestral character
This trait is derived at some point but does not include all of the ancestors in the tree. An evolutionary novelty unique to a particular clade.
Shared derived character
Uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change. The number of nucleotide substitutions in related genes is assumed to be proportional to the time since they last shared a common ancestor.
Molecular Clock
The movement of genes from one genome to another. Ex.) mrsa or antibiotic resistance.. don’t want this transfer to good bacteria
Horizontal gene transfer
Reveals changes in the history of life on Earth. The relative ages of fossils can be determined by their sequence in the rock strata. The absolute ages of fossils can be determined by radiometric dating. Each isotope has a known half-life (the time required for half the parent isotope to decay)
Fossil Record
The oldest known fossils. Rocks formed by the accumulation of sedimentary layers on bacterial mats. Date back to 3.5 billion years ago.
Stromatolites
Earth’s apparent age is what?
4 billion years
How old is eukaryotes?
1.8 billion years old
How old are prokaryotes? Prokaryotes were Earth’s sole inhabitants for more than 1.5 billion years.
3.5 billion years old
Scientists believe there were how many mass extinctions? Which one are we in right now?
There were 5, we are in the 6th now
- In each of the 5 mass extinction events, 50% or more of MARINE species became extinct
Early prokaryotes released oxygen into the atmosphere through the process of photosynthesis. The increase in atmospheric oxygen that began 2.4 billion yrs ago led to the extinction of many organisms. The eukaryotes flourished in the oxygen-rich atmosphere and gave rise to multicellular organisms.
Origin of Eukaryotes
The Origin of New Groups of Organisms
Mammals belong to the group of animals called what?
- The evolution of unique mammalian features can be traced through gradual changes over time.
tetrapod
The history of life on Earth has seen a rise and fall of many groups of organisms. The rise and fall of groups depend on what 2 rates within the group?
speciation and extinction
Is a Six Mass Extinction Under Way?
Scientists estimate that the current rate of extinction is 100-1,000 times the typical background rate. Extinction rates tend to increase when global temperatures increase. Data suggest that a sixth, human-caused mass extinction is likely to occur unless dramatic action is taken.
The fossil record shows that most species that have ever lived are now what?
extinct
Can be caused by changes to a species’ environment. It is a process in which new forms arise by the slight modification of existing forms.
extinction
At times, the rate of this has increased dramatically and caused this. It is the result of disruptive global environmental changes.
Mass Extinction
Can alter ecological communities and the niches available to organisms. It can take 5-100 million years for diversity t recover following a mass extinction. The type of organisms residing in a community can change with this.
Mass Extinction
The evolution of many diversely adapted species from a common ancestor.
Adaptive Radiations
Adaptive Radiations may follow:
- Mass Extinctions
- The evolution of novel characteristics
- Colonization of new regions
An evolutionary change in the rate or timing of developmental events. it can have a significant impact on body shape.
Heterochrony
What is used to determine phylogeny?
a.) mutations
b.) DNA
c.) evolutionary history
d.) organisms on earth
c.) evolutionary history
What do scientists in the field of systematics accomplish?
a.) discover new fossil sites
b.) organize and classify organisms
c.) name new species
d.) communicate among field biologists
b.) organize and classify organisms
Which statement about the taxonomic classification system is correct?
a.) There are more domains than kingdoms.
b.) Kingdoms are the top category of classification.
c.) Classes are divisions of orders.
d.) Subspecies are the most specific category of classification.
d.) Subspecies are the most specific category of classification.
Which statement about analogies is correct?
a.) They occur only as errors.
b.) They are synonymous with homologous traits.
c.) They are derived by similar environmental constraints.
d.) They are a form of mutation.
c.) They are derived by similar environmental constraints.
What do scientists use to apply cladistics?
a.) homologous traits
b.) homoplasies
c.) analogous traits
d.) monophyletic groups
a.) homologous traits
What is true about organisms that are a part of the same clade?
a.) They all share the same basic characteristics.
b.) They evolved from a shared ancestor.
c.) They usually fall into the same classification taxa.
d.) They have identical phylogenies.
b.) They evolved from a shared ancestor.
The transfer of genes by a mechanism not involving asexual reproduction is called:
a.) meiosis
b.) web of life
c.) horizontal gene transfer
d.) gene fusion
c.) horizontal gene transfer
What does the trunk of the classic phylogenetic tree represent?
a.) single common ancestor
b.) pool of ancestral organisms
c.) new species
d.) old species
a.) single common ancestor
