Midterm 2 Flashcards
What is human-mediated evolution?
Evolution which occurs as a result of human activities.
What is artificial selection?
Rapid changes in a population of domestic animal or plants through breeding for select traits.
What is traditional breeding?
Traditional breeding is the selection for pre-existing traits in a species. Intentional activity where organisms with perceived beneficial traits are bred and organisms which don’t have those traits are not allowed to reproduce (plant breeding, animal husbandry).
What is genetic engineering?
Genetic engineering is the intentional transformation of the genome.
What is taming?
Conditioned behavior in a wild-born animal involving reducing is natural avoidance response to humans.
What is domestication?
Phenomenon where one organism assume responsibility for the care and reproduction of the second organism.
What is population sire effect?
It’s the over representation of certain genes in the next generation due to the over breeding of an animal with superior traits.
Over time, offspring from this animal may make up a disproportionately large proportion of the next generation, and so its negative traits, which might lead in a population bottleneck.
What is agrobacterium tumefaciens?
A parasitic species of bacteria that can insert the DNA of its plasmid into plant host and it’s now used to do genetic engineering.
What is CRISPR/Cas9
A natural immune system against viruses and pathogenic plasmids in prokaryotes. It destroys viral DNA by cutting DNA strand. Modified, it allows us to specifically choose which genes to cut out and which genes to insert in the organism.
What is gene drive technology?
During sexual reproduction, an organism equipped with CRISPR/Cas9 could potentially see the CRISPR/Cas9 system modifying the DNA of BOTH parents as the embryo develops.
How have humans practiced artificial selection?
By plant breeding and animal husbandry.
In what way can we used CRISPR/Cas9 to affect other species?
- Resisting pathogenes
- Limiting fertility in invasive species
- Increasing fertility in endangered species
- Destroying population
How novel gene-editing technologies can direct evolution?
By mixing genes in different species.
What kind of selection is traditional breeding?
Directional selection because breeding attempts are generally focusing on a single trait.
What are the desirable traits in animal husbandry?
- Harvestable commodity
- Ability to be domesticated
- Useful role
- High fecundity
What are the limitation of traditional breeding?
- The pre-existing genes in a species
2. The number of other species that could hybridize
What is the big revolutionary thing about genetic engineering?
Possibility to combine desirable genes of two different species that could never naturally breed.
What is the big revolutionary thing about genetic engineering?
Possibility to combine desirable genes of two different species that could never naturally breed.
What are the big problems with A. tumefaciens?
- There is no control over where the bacteria inserts it’s DNA into the genome of the host.
- You can’t insert bacterial DNA into a fully mature plant.
- To transform al the cells of a plant, you need to develop an embryo on a artificial growth media, which is itself costly and take long studies to develop.
How do you test to see whether the DNA has inserted into the correct position with A tumefaciens?
You need to test each and every plant (long and costly).
What are the desirable traits in commercial flowers?
- Herbicide tolerance
- Pest and disease resistance
- Comercial compounds
- Flower color
- Longer flower life
- Longer shelf life
- Better nutrition
What are the big advantage with CRISPR/Cas 9?
- Specifically choose which genes to cut out and where to put it in the organism.
- Less costly and time consuming
- Guarantees that the trait will be inherited because CRISPR in one parent can modify the genes of the other parent in the developing embryo. (gene drive technology)
On what should editing of human embryos should be limited?
On eliminating genetic diseases.
Why is New Zealand one of the countries most severely impacted by invasive species?
Because it’s an island nation with naïve fauna that has stable temperate environment and different habitats (alpine mountains to lowland forests).
What are the unintended consequences of human activity on the evolution of other species?
- Pollution: tolerance to pollution
- Founder effect: Introduction of invasive species through small founding population
- Population bottlenecks: Population loss in native species
- Artificial landscapes: Modifying behavior because of artificial landscapes
- Pesticides: Resistance genes in weed plants and insect species agains pesticide
- Antibiotics: Mutation and spread of antibiotic resistance genes.
- Failed biological control
- Unintended natural selection: our activities can increase genes in the gene pool which would otherwise decrease fitness
Something to remember about human drive evolution
Same pattern but much faster than natural evolution because high selection pressure
Do artificial selection follow traditional evolution?
No. Specific traits are selected for artificially in a population, mutations are not random.
What are introduced /non-native/ exotic species?
A species which has been introduced to an habitat that it has not historically been found in.
What is a negative impact?
Any impact on environment which reduces/degrades:
- species diversity
- total number of individual organisms
- physical environment
What is a novel environment?
An environment a species has never inhabited before.
What is genetic pollution?
When a native species experience excessive hybridization with an introduced species.
What is an invasive species?
An introduced species which is having a negative impact on the novel environment it is in. (CAN’T BE A NATIVE SPECIES ENVEN IF IT HARM THEIR ENVIRONMENT).
What is the invasion potential?
The ability of a species to become an invasive species in a novel habitat (based on anthropocentric values).
What defines establishment?
- Survival
2. Successful reproduction
What are the characteristics that an environment that has great number of introduced species tends to have?
- Warm
- Consistent rainfall
- Stable weather
What is the lag phase?
The period of time when a newly established species must increase in number before starting to spread.
What are the waves of introduction?
Other individuals of the same species brought to the novel habit which allow gene flow between source and founder populations.
Can impact phase overlap with spread phase?
Yes
What are the general traits associated with greater invasion potential?
- High fecundity
- Asexual reproduction
- Generalist in habitat preference and food need
- Defensive/hunting strategies not found to the novel environment
What is propagule pressure?
Measure of the number of individuals of a species released into a region to which they are not native
What is prey naiveté?
When a prey species has no defensive response to a predator species.
What is predator release?
When a introduced species is found in a novel environment where few or no species hunt it.
What are the factors in the novel environment that helps survival of invasive species?
- Prey naiveté
- Predator release
- Open niches
Define biodiversity.
Many different species and types of species.
So in what can we measure the invasiveness of a species?
- Trait of the introduced species
2. Characteristics of the novel environment.
What is invasion meltdown?
Where and invasive species negatively impacts multiple native species both directly, and indirectly by modifying the abiotic environment.
What is biological control?
The intentional introduction of a non-native species to control another (usually non-native) species.
What are the changes in the novel habit that invasive species can bring?
- Selection pressure on native species (evolution of prey response, behavior)
- Ecosytem and abiotic effects
What are the changes in the novel habit that invasive species can bring?
- Selection pressure on native species (evolution of prey response, behavior)
- Ecosytem and abiotic effects (often through the loss of another species)
What are the two classes of intentional introductions?
- Biological control
2. Intentional for human use
How do we define an individual in biology?
Generally, a separate organism. It depends on the situation.
In studies of population: it can be useful to consider clones as individuals.
In evolution studies: it can also be useful to consider clones as individuals. Clones can reproduce asexually and spread somatic mutations, and colonial organisms are still subject tu mutation and selection pressure (kin selection).
What are the various theories regarding species definition? How each one falls appart?
There is 26 accepted. No single one applies to all species.
Biological (asexual), evolutionary and operational.
Hybrid vigor:
Term used to describe an hybrid that is more vigorous that its parents.
What is a species in biologoy?
- A specific taxonomic rank
2. A biological classification
Why don’t we see more hybrid in the wild?
- Ranges may not overlap
- Different courtship rituals
- Sterile offspring
Evolutionary species concept:
Lineages that are evolutionarily independent in their passage through time (branches of phylogenic tree are different species).
Operational species concept:
Smallest sample of self-perpetuating organisms that have a unique set of characters that can be defined by analytical techniques.
The species problem:
Difficulties to find a theory which can
- Apply to both asexual and sexual species
- Differentiate chronospecies
- Classify hybrids
Speciation:
Creation of new species
Chronospecies:
Two or more species separated by time, the first of which appears to have developed into the second (fossil record).
What is the problem with biological species concept?
Do not always interbreed freely ( asexual species, may not breed, lateral gene transfer)
Hermaphroditic species:
Species formed by organisms that have both female and male organs.
What is the avantage with the evolutionary species concept?
Includes asexual species, chronospecies and fossils.
Cryptic species:
Species which are difficult to tell appart by physical characters alone.
DNA barcoding:
Short genetic sequences from an unknown species that can be compared to an existing phylogenetic tree to determine relationships to another species.
Molecular phylogeny:
Determine evolutionary relationships between organisms by examining and comparing heredity molecular differences.
What are the avantages with operational species concepts?
Includes asexual species and hybrids.
What is the limitations in DNA techniques?
How genetically different two organisms need to be in order to make two different species.
What species concept should you choose if you are trying to identify a species for identification purpose?
Operational definition
What species concept should you choose if you want to discuss how species are formed and maintained?
Evolutionary definition
What species concept should you choose if you are working with sexually-reproducing and isolated population?
Biological species concept
Macroevolution:
Evolution which occurs over a large taxonomic group over a long period of time (fossils)
Microevolution:
Evolution which occurs in a population over a short period (genes)
Anagenesis:
A single species that evolve in another species over time (chronospecies)
Cladogenesis:
A single species that evolve into two or more species over time
Creeps:
Gradual process
Jerks:
Sudden and abrupt change
Gradual speciation:
Species arise slowly over time with many morphological intermediates.
Punctuated equilibrium:
Species arises through quick divergences and then remains unchanged over long period of time.
Intermediate forms:
Evolutionary steps between an ancestral species/trait a population/trait seen today/more recently.
Rate of trait evolution:
The evolution of trait without relation to species.
Taxonomic rates of evoulution:
The rate at which a taxa evolves (species, genus, family, etc).
Key innovations:
Novel and sudden phenotypic adaptation to one or more ecological zone
Irreductible complexity:
Traits whose functions have become so essential to life that loosing them through evolution seems impossible
Selective ratchet:
Traits not easily dispensed with because of their role in functional integration ex: notochord
Specialization:
A species loosing general traits to become better adapted to a very specific habit
Quantum speciation:
Unexpectedly rapid speciation seen in punctuated equilibrium and often seen in in small population under the impact of founder effect.
Mass extinction:
An extinction event where species extinction vastly exceed the historical background rate of species extinction
Adaptive radiation:
Rapid speciation and evolution events.
Ecological niche:
The specific place a species holds in its environment and the role it plays in the food chain of that community.
What are the main issues with gradualism?
- Why does evolution continue if intermediate forms are adaptative
- How can intermediate forms have evolved, were they useful?
- How would primitive organ arise if they require many different complex mutations?
How did the eye evolve?
- Fossils found of intermediate forms
- Intermediate forms persist which make them useful
- Different types of organs in different taxonomic clades suggest shared evolutionary history
What are the characterisitics needed for punctuated equilibrium to occur?
- Short: single or few mutations de novo mutation must occur in a short period of time
- Significant and adaptative: mutations must be severe enough to cause noticeable changes without decreasing the fitness
- Facilitates isolation: Kind of reproductive or geographic isolation between species
Define complex organism.
Organism which has a big number of unique individual organs or traits.
Can a species regain a trait lost through evolution?
Rare, but possible ex: viviparous lizard.
What are the trends in trait evolution?
- Severe mutation are extremely unlikely ex:axolotl
- From unicellular to eukaryotes, there is an increase in complexity
- After that, the complexity/specialization tend to decrease
When is there an abundance of open niches that leads to adaptative radiation?
- Mass extinction
- Development of new traits which confer access to new niches
- Modification in habitat which creates new niches
What is the Albian-Aptian gap?
Historical period where the dominant plant group gradually changed from conifers to angiosperms
Allopatric speciation:
Speciation caused by the geographic isolation of two different populations. (Gene flow can occur but must be rare).
Vicariant speciation:
Type of allopatric speciation where the two populations involved in speciation are approximately equal.
Peripatric speciation:
Type of allopatric speciation where one population must be much smaller than the other.
Island Rule (Foster’s Rule):
Species arisen through peripatric speciation either underwent insular dwarfism and gigantism
Insular dwarfism:
Animals which are larger on mainland tend to become smaller on an island.
Insular gigantism:
Species which are smaller on mainland tend to become larger on islands.
Centrifugal speciation:
Mechanism of peripatric speciation ( which is a type of allopatric speciation) where speciation occurs by a series of range expansion and contraction.
Parapatric speciation:
Speciation which occurs when the ranges of two speciating population are overlapping
Sympatric speciation:
A species arises from within a range overlapping with its origin species.
Reproductive isolation:
Imcompatible reproductive methods that restrict gene flow even in overlapping populations (different courtship ritual or infertile hybrid).
Hybrid speciation:
Speciation from the hybridization of two (or more) different species.
Speciation through sexual selection:
Speciation which occur because the sex that selects the mate switches its preferences (sympatric).
Can species arise when there is a lot of gene flow between two populations?
No
Extinct:
Death of the last individual of a species.
Extinct in the wild:
Death of last individual of a species in the wild. ex:Père David’s deer
Functionally extinct:
A species which still has members present in the environment but have decreased below their minimum viable population, that are preventing from recovering because of obvious factors or are no longer performing their role in the ecosystem. ex: baji dolphin
Why do we tract extirpation?
Loss of genetic diversity when we lose a population decreases the health of a species.
Fossil record:
Term for the history told by accumulated fossils.
Background rate of extinction:
An average number of families that went extinct over millions of year.
Mammals=1 million years
Arthropods=11 million years
Living fossil:
Unchanged species for a long period of time, way above their rate of extinction.
Muller’s ratchet:
Deleterious mutations build up in asexual populations.
*asexual single-celled species survive well through lateral gene transfer
Coextinction:
When the extinction of one species cause the extinction of a second dependant species (parasite/host, obligate mutualism, specialized predators)
Lazarus taxa:
Species once believed to be extinct which are later rediscovered.
De-extinction:
Intentionally bringing a species back from extinction
Pseudoextinction:
The apparent extinction of a species which has become a new species or sub-species.
Planned extinction:
Directed human effort to drive a species to extinction
What are some biotic traits of a species suited to avoid extinction?
- Extremely common
- Generalist
- High fecundity
- Excellent disperser
- Short lifecycle
