Genomes to Ecosystems Flashcards
What is a colonial organism?
Colonial organisms are clonal colonies composed of many physically connected, interdependent individuals. The subunits of colonial organisms can be unicellular, as in the alga Volvox (a coenobium), or multicellular, as in the phylum Bryozoa.
What causes coral bleaching?
The thylakoid membranes inside the symbiont have photosystems which capture photons and initiate photosynthesis. Overexposure to photons causes the photosystems to break. Despite the failure of the photosystem’s capacity, the phoptons are still moving into the thylakoid membranes creating reactive oxygen molecules which damagesthe inside of the coral cell resulting in ejection of the symbiont. Enough symbiont ejection causes the eventual bleaching of the coral.
What are ecosystem services?
A way of monetising the value of an ecosystem to human populations. Monetising ecosystem services is an important means for ecologists and conservation biologists to engage with government and industry.
What are examples of ecosystem services that coral offer?
- Habitat for fisheries
- Biodiversity
- Medicine/Drug Discovery
- Carbon sinks
- Tourism
What is a Marine Protected Area?
Equivalent to National parks and essentially provide conservation status and prevent physical damage to reef and associated animal and plant communities.
How much of the ocean is a ‘no-take’ zone and
Only 0.5% of Marine Protected Areas are a ‘no-take’ zone (cannot fish or remove any organisms) and only 4% are protected.
What is the likely principle driver of coral bleaching?
It is likely the main driver of coral bleaching is more intangible and much harder to address - i.e. climate change.
How is CO2 affecting the oceans?
Increased CO2 is causing acidification (carbonic acid) which makes carbon deposition all the harder.
What is pattern in terms of evolution and how are they useful to us?
Pattern is the change we see in the fossil record through time. We can infer evolutionary relationships bewteen fossil orgainsms and their living descendants.
What does evolution assume about all organisms?
Evolution assumes that all organisms, extinct or extanct are in some way related.
What does extant mean?
Extant means still in existence; surviving.
Phylogenetic Tree of Whales
What is a Phylogenetic Tree? What do they show?
A phylogenetic tree is a diagram that represents evolutionary relationships among organisms. Phylogenetic trees are hypotheses, not definitive facts.
The pattern of branching in a phylogenetic tree reflects how species or other groups evolved from a series of common ancestors.
In trees, two species are more related if they have a more recent common ancestor and less related if they have a less recent common ancestor.
Phylogenetic trees can be drawn in various equivalent styles. Rotating a tree about its branch points doesn’t change the information it carries
What drove the evolution of modern whales?
- Ecological opportunity in the shallow equilatorial Tethys ocean
- Abundant marine food sources in the shallows
- The process which drove the evolution of modern whales is natural selection and ecological opportunity.
What were the prior accepted theories of evolution?
Scalae Naturae
- A solid march towards ‘perfection’.
- Slime moulds at the bottom, us at the top.
Theistic Evolution
- Divine creation
- God generating beneficial mutations
- Asa grey and others
Orthogenesis
- Directional force driving evolution
- Evolution is non-reticule
- Various proponents
Mutationalism
- Species emerge in large jumps
- Also ‘saltationism’
- Hugo de Vries 1900
Lamarckianism
- Individuals lose characteristics they don’t need
- Acquired traits are heritable
- JB Lamarck (1809)
What is Darwin’s theory of evolution?
Assumptions
- Every species is fertile enough that if all offspring survived to reproduce, the population would grow.
- Despite periodic fluctuations, populations remain roughly the same size.
- Resources such as food are limited and are relatively stable over time.
Struggle for Survival Ensues
- Individuals in a population vary significantly from one another and much of this variation is heritable.
- Individuals less suited to the environment are less likely to survive and less likely to reproduce; individuals more suited to the environment are more likely to survive and more likely to reproduce and leave their heritable traits to future generations, which produces the process of natural selection.
- This slowly affected process results in populations changing to adapt to their environments, and ultimately, these variations accumalate over time to form new species.
What were the flaws in Darwinian Evolution?
- Darwin stated that a portion of inter-individual variation must be heritable. He just didn’t really know what caused the heritable.
- Darwin developed ‘pangenisis’ theory of evolution involving ‘gemmules’ which were produced by all tissues.
- Pangenisis had a Lamarckan twist.
What are Mendel’s two rules of inheritance?
Menedel studied inheritance of seven phenotypic traits.
- Developed two key ‘rules’ of inheritance
- Law of segregation (gametes)
- law of independent assortment (prophase 1)
- Described genes as factors
What is Modern Synthesis?
What is stabalising selection?
Normal Distribution of Trait in a Population
- Take a hypothetical population of organisms.
- Trait is the phenotype under selection (e.g. tail length)
- Variation in trait values might be normally distributed w/o selection.
Stabalising Selection
- Selection against extreme trait values
- Phenotypic variationlost from population
- Mean trait value stays the same
What is Directional Selection?
Normal Distribution of Trait in a Population
- Take a hypothetical population of organisms.
- Trait is the phenotype under selection (e.g. tail length)
- Variation in trait values might be normally distributed w/o selection.
Directional Selection
- Selection against extreme trait values
- Mean trait value moves in response to the direction and intensity of the selection.
What is the equation for the heritability of a trait?
The heritability (h2) of any given trait is the ratio of the genetic variation to total phenotypic variation:
h2 = VG / VP
What is a way of measuring heritability directly?
A way of measuring heritability directly is to look at how well trait values correlate between generations. I.e. How much do we look like our parents?
The gradient/regression line is the heritability of the trait; h2.
What does the breeder’s equation?
The greater the heritability of a trait, the faster a species can respond to selective pressure - the breeders equation:
R = h2S
R = Evolutionary response; the change in phenotype between generations
h2 = Heritability; tranmissibility of phenotype
S = Selection differential; change in phenotype due to selection
What is sexual selection?
Natural selection arising through preference by one sex for certain characteristics in individuals of the other sex.
There are 2 mechanisms for sexual selection:
- Intrasexual selection, or competition between members of the same sex (usually males) for access to mates (accepted immediately).
- Intersexual selection, where membersof one sex (usually females) choose members of the opposite sex.
What is comaparative anatomy?
Comparative anatomy, the comparative study of the body structures of different species of animals in order to understand the adaptive changes they have undergone in the course of evolution from common ancestors.
What are the three ways of determining common ancestors?
The three ways of determing common ancestors are:
- Morphology
- Fossil evidence
- Genetics
How much of the mitochondrial DNA and nuclear DNA do we inherit from our parents?
We inherit 100% of the mitochondrial DNA from our mothers. We also gain 50% of each parent’s nuclear DNA.
The Molecular Clock
What is a swim bladder in bony fish?
Swim bladder, also called air bladder, buoyancy organ possessed by most bony fish. The swim bladder is located in the body cavity and is derived from an outpocketing of the digestive tube.
6 Stages of succession
