Midterm 2 Flashcards
(124 cards)
1
Q
Speciation
A
The point where a new trait emerges and new branches form. Becomes different from the parent population and becomes a new species.
2
Q
Node
A
The point on the tree branch where the ancestral population splits into separate populations
3
Q
Species (general)
A
- Ability to reproduce
- The entire unit of the organism
- No definition applies to all cells
4
Q
Biological species concept (Name all factors)
A
- It is the explanation of how speciation occurs.
- All members can interbreed under natural conditions and produce fertile offspring
- Some hybridization is ok
5
Q
Hybridization
A
When two different species come together and reproduce. These organisms are usually not viable and can’t reproduce.
6
Q
Sterile
A
Unable to reproduce
7
Q
Limitations in the biological species concept
A
- Asexual organisms. They can’t reproduce the same way sexual organisms do
- Not always clear who has the “potential” to interbreed. Can be hard to apply
- Can’t be applied to fossils
8
Q
Crossed boundry
A
When a new species is created and a new population is formed
9
Q
Boundary arbitary
A
Dog x Wolf. When hybridization leads to fertile offspring
10
Q
Morphological species
A
Characterizes a species by their body shape and other structural features
11
Q
prezygotic barriers
A
Prevents the formation of a zygote or a fertilized egg
12
Q
Habitat isolation
A
They prefer different habitats so they never/rarely mate. Ex: maggot fly
13
Q
Temporal isolation
A
Species may encounter each other and interbreed but are “ready” to mate at different times. Time and season are important factors. Ex: plants and animals
14
Q
Behavioral isolation
A
Species may encounter each other but don’t mate because of differences in courtship or behavior. Ex: firefly blinking patterns or bird songs
15
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Mechanical isolation
A
Lock and key. The shape of where you mate has to fit like a puzzle piece. Ex: inspects and flowers
16
Q
Gametic isolation
A
Games do not recognize each other due to different receptors!!
17
Q
Reduced hybrid viability
A
When the hybrid is weak and is not able to survive. Not a good fit for the habitat. Ex: sticklebacks
18
Q
Hybrid infertility
A
When the hybrid is healthy but is unable to reproduce. Ex: mules and tigons
19
Q
Hybrid breakdown
A
1st generation is fertile and the 2nd generation is weak. Each generation keeps getting weaker and weaker
20
Q
Postzygotic Barriers
A
Prevents the development of viable or fertile offspring
21
Q
Habitat Isolation
A
They prefer different habitats so they never/rarely mate
22
Q
Temporal Isolation
A
Species may encounter each other and interbreed but they are “ready” at different times. The time and season may be different. Ex: Plants and animals
23
Q
Behavioral Isolation
A
Species may encounter each other but don’t mate because of differences in courtship or behavior.
Ex: Firefly blinking pattern or bird songs
24
Q
Mechanical isolation
A
Lock and key. The shape of where you mate has to fit like a puzzle piece. Ex: Plants and humans can’t mate
25
Gametic isolation
Gametes do not recognize each other due to different receptors
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Reduced hybrid viability
When the hybrid is weak and not able to survive. Not a good fit for the environment. Ex: sticklebacks
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Hybrid infertility
They can be very healthy but they can't reproduce. Ex: Mules and tigons
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Hybrid breakdown
1st generation is fertile and 2nd generation gets weak. Each generation keeps breaking down
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Macroevolution
Broad patterns of evolutionary change above the species level. Can produce major change if there is enough time
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Evolutionary change
Natural selection, genetic drift, gene flow, mutations
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What does evolution is a tinkerer mean?
Evolution that includes small modifications to already existing traits.
- Something with a trait that isn't being used starts using the trait in a good way
- Evolutionary dead ends force having to adjust and having to work with what you have.
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Anagenesis
Patterns of change overtime
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Cladogenesis
Patterns of diversification
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Gradualism
Slow change over time and connects to darwinian views.
| Example: Distinction among fossil species
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Examples of contrasts to gradualism
Bacteria reproducing, epigenetics, bottleneck genetic drift
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Punctuated equilibrium
Emphasizes periods of stasis interspersed with periods of "rapid" change. This means that there is no change and then there is a period of rapid change
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Stasis
Long periods of subtle evolutionary change. Even though lineages have very small change over time, they will still evolve
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Living fossils
Organisms that show almost no change from the very beginning. There is still change though, evolution is just not seen and might be part of the molecular level
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What is causing stasis
It is not always clear about why it happens. Can be due to stabilizing and directional selection
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Genetic constraints
1. Continued use of old features in the absence of variation or directional selection
2. Mosaic evolution
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Mosaic evolution
When there is a different rate of evolutionary change in various body structures and functions within a population. Changes are taking place independently of other parts.
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Rapid change
Origin of new species and characteristics over a time period that is quick and short relative tot eh period of stasis. Can be caused by environmental change
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Environmental example of rapid change
Cambrian explosion (the sudden appearance of every animal phyla)
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Extrinsic factors
Provides opportunities to occupy previously unavailable niches
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Adaptive radiation
a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches
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Intrinsic factors
Characteristics that open up new opportunities
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6 Origins of evolutionary novelty
1. Exaptation
2. Duplication
3. Serial Homology
4. Heterochrony
5. Horizontal gene transfer
6. Homeotic gene and pattern formation
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Exaptation
The concept that evolution is seen as a tinkerer. Example: Flowers are modified leaves
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Duplication
Evolution of genes with novel functions. Duplicated genes can evolve different functions
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Globin genes
Duplicated genes that can evolve different functions
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Serial homology
Repetitive segments in the same organism. Modifying a specific structure more than once and using it somewhere else
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Heterochrony
Changes in developmental timing can alter the appearance of organisms. Indevolpment
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Horizontal gene transfer
Horizontal movement of individual genes, organelles, or fragments of genomes from one lineage to another. This happens a lot in bacteria
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Homeotic gene and pattern formation
Simple developmental/genetic changes that can have major effects
- Genes that alter the body plans of organisms
- Homeotic mutations in Arabidopsis thaliana flowers
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Hox genes
Related genes that are essentially found in all animals. Help lay out the basic body forms of many animals
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Analogous traits
Similarities that are independently evolved. AKA. Convergent
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Homologous traits
Traits that are similar in structure but have very different functions. Traits shared by two or more different species that share a common ancestor.
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Important aspects of a phylogenetic tree
1. Living species are all the way at the top
2. Branches represent groups of closely related species
3. The points on each branch are speciation events
4. Organisms are united to varying degrees by shared ancestry and share a surprising number of features across a range of lifestyles
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Problem with constructing trees by fossils
Hard to interpret
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Phylogeny
The branches and connections on Darwin's tree of life
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Systematics
Using classification to reflect the phylogeny of organisms
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Cladogram
An overall estimate of relationships. Groups that are closer together share a more recent common ancestor than those that are farther apart
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Clade
A grouping that includes a common ancestor and all of its descendants. Nested within one another and form a nested hierarchy
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Synapomorphy
Shared derived traits
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Derived traits
Present in the organism but absent in the common ancestor
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Convergent trait
Similarities that evolve independently of each other.
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Primitive trait
Inherited from distant ancestors
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Methods and evidence scientists use to put dates on events
1. Radiometric dating
2. Stratigraphy
3. Molecular clocks
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Radiometric dating
Radioactive elements allow scientists to date rocks and materials directly
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Stratigraphy
A sequence of events from which dates can be extrapolated
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Molecular clocks
Allow scientists to use the amount of genetic divergence between organisms to extrapolate backwards to estimate dates
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Monophyletic
The ancestral species and all of the descendants grouped together. A CLADE
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Paraphyletic
Recent ancestor is included but not all of the descendants. A single origin + does not imply a close relationship
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Polyphyletic
Does not include the recent ancestors. Usually just some of the descendants.
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Can cladograms be rotated at the node without changing the relationships between the sister taxa?
Yes. What matters is which lineage the taxa descends from
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2 principle techniques for reconstructing phylogeny
1. Parsimony
| 2. Outgroup analysis
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Parsimony
Cladogram requiring the fewest evolutionary changes is the most preferred. Using the simplest explanation for the distribution of characters gives us a reasonable and explicit goal
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Outgroup Analysis
Distinguishing derived from primitive similarity. The most different from all the other organisms
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Taxonomic system
Species that are closely related are grouped into the same genus
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Branch points
Compare relationships of evolutionary history
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Root
Represents the most common ancestor of all the taxa
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Criteria for defining a living organism
1. Cellular organization
2. Means of metabolism
3. Information storage
4. Self replication
5. Responding to stimuli in the environment
6. Maintaining homeostasis
7. Reproduction
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Means of metabolism
Different ways to acquire energy and metabolize
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Information storage
Coding for and storing information: RNA and DNA
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Are viruses living or nonliving
Nonliving
86
Why are viruses nonliving?
1. They can only reproduce inside of a host cell
2. Since they do not have ribosomes, they have to take over the ribosomes and metabolic state of the host
3. They do not maintain homeostasis outside of the host cell
87
When was earth formed
4.5 billion years ago
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3 early earth environmental comparisons to today
1. There were a lot of volcanoes relative to now
2. Oxygen was present in a small amount
3. CO2, H2, and N2 were all present
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First form of life
Prokaryotes
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Oxygen levels in early earth
Atmospheric oxygen concentration was very low
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When did oxygen levels begin to increase
Photosynthesis
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How did iron oxide form
Oxygen dissolved in water and reacted with iron
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Banded iron formation
Oxygen dissolved in water and reacted with iron. This accumulated in alternating layers of red and dark rock.
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Earliest evidence of photosynthesis
Banded iron formation
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Fossil stromatolities
Provide an early record of photosynthetic organisms
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What formed stromatolities
Cyanobacteria
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When did prokaryotes rule and change the earth
Between march and october
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When did the first bacteria emerge
March
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Before october
Only single celled organisms were around
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After october
Multicellular organisms began to show up
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November
Plants invaded the land and most major animal groups appeared in oceans
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Early december
Flowers and mammals evolved
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December 26
Dinosaurs ruled the world until the asteroids hit. Only the birds survived
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December 31st
Humans began existing
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Modern Cell theory
1. The cell is the smallest living unit in all organisms
2. All living things are made up of cells
3. All cells come from pre existing cells
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2 types of prokaryotes
Bacteria and Archea
107
Type of Eukaryote
Eukarya
108
Prokaryote
Unicellular organisms
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Eukaryote
Unicellular or multicellular organisms
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Which is closer to the Eukarya
Archaea
111
Similarities between Prokaryotes and Eukaryotes
1. DNA
2. Ribosomes
3. Cytoplasm
4. Cell membrane
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What do ribosomes do
Ribosomes make protein
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What does the cell membrane
Controls what goes in and out of the cells - maintaining hoeostasis
114
Unique to prokaryotic
- No nucleus, free roaming genetic information
- No membrane bound organelles
- No nuclear envelope around genetic material
- Circular DNA
- Binary fission: No mitosis or meiosis
- Few genes in the plasmids
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Unique to eukaryotic
- More detailed cell materials
- Some don't have cells walls while some do
- More complex and larger
- Has nucleus
- Has membrane bound organelles: nucleus, mitochondria, endoplasmic reticulum, golgi appartus
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Circular Dna
Has genes for resistance
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What was the dominant form of life on earth
Prokaryotes
118
Prokaryotes were ___x the mass of all eukaryotes
10x
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What type of respiration do prokaryotes do?
- Aerobic
- Anearobic
- Photosynthesis
120
Where does all of our metabolism come from
Prokaryotic metabolism
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What is the molecule that bacteria has in their cell wall that is not found anywhere else
Peptidoglycan
122
Peptidoglycan
Only found in the cell wall of bacteria. They stack up in certain groups of bacteria
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How many prokaryotic cells are in your gut
10^14
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How many cells make up your body
10^13
