Genomes to Ecosystems Flashcards
What makes corals turn white and become bleached
When they expel there symbionts that give coral its tan colour, they appear white.
Why does coral expel its symbiont and why is this such a large issue?
When temperature and light go up, the photosystems in the dinoflagellate break. The rain of photons doesn’t stop however and that energy is turned into reactive oxygen species that damages the coral. In response to this, the coral kicks out the dinoflagellate, which provides 75-90% of its energy, making the coral white.
Why is coral bleaching such an issue in islands like the Maldives?
Coral grows in shallow water and can act as a wave breaker for islands, slowing down the water before it reaches the shore.
Why is coral so sensitive to global warming and increased CO2 emissions?
Shallow water, where coral lives, heats up much faster than deep water. So when temperatures rise, the water quickly does as well. When there is a lot of carbon dioxide in the air, it can dissolve into water and raises acidity levels in the water. This increased acidity reduces the availability of of carbonate ions which coral usually combines with calcium to build its skeleton.
What is the difference between facultative and obligate endosymbiosis?
Endosymbiosis is a relationship where one organism lives inside another. Obligate endosymbiosis is when the organisms or an organism needs the host to survive. Facultative endosymbiosis is when both species can live independently.
What are some examples of human driven stressors to coral?
CO2 emissions and climate change cause sea surface temperatures to rise and less carbonate for coral skeleton
Ozone depletion increases solar irradiance which breaks photosystems
Deforestation - more carbon in atmosphere and soil erosion can end up in coral reefs.
Deep sea fishing can cause a prey overabundance e.g. too much algae.
How can coral act as a carbon sink?
Coral takes carbon from the atmosphere and fixes it into its skeleton. The oxygen it breathes out is negated by the dinoflagellates.
What ecosystem services do coral reefs provide for humans?
- Tourism
- Costal protection (wave break
- Carbon sinks
- Habitats for fisheries
- Drug discovery
- Biodiversity
What mechanisms can be used to try conserve coral reefs?
- Protection of coral reef
- Awareness campaigns to bring this issue to light
- Coral gardening to replant coral in damaged reefs
3a. Genetic selection- purposely selecting coral that survives in artificially harsh environments - Finding more robust dinoflagellate e.g. from hotter areas and introducing them to coral. The coral must be flexible and not selective for this to work.
What is an ecosystem?
An ecosystem is the biological community living in an area (biota) plus the physical, chemical and climatological conditions that make up its abiotic environment and the interactions between these.
What are the primary ecosystem processes?
Energy transfer- energy is captured from the sun and transferred into the ecosystem (external source).
Nutrients, water and CO2 cycling- come from within the ecosystem and are cycled from form to form by the ecosystem processes
What are ecosystem processes and what are some examples?
Ecosystem processes are the mechanisms that the primary ecosystem processes rely on e.g. photosynthesis, decomposition, predation
What is the meaning of ecosystem functioning?
The capacity of ecosystems to carry out the primary ecosystem processes.
What are ecosystem goods and services and why are they important?
The benefits the ecosystem provides for humans. In the past humans undervalued ecosystems and destroyed them. Ecosystems don’t replenish quickly so this puts a monetary value on ecosystems to encourage protection to governments
What is the difference between supporting services and ecosystem processes?
Supporting services are the ecosystem processes necessary to produce all other ecosystem services, such as regulating and cultural services.
Ecosystem processes are the mechanisms that contribute to ecosystem functions.
What are all the ecosystem goods and services?
- Supporting services: necessary for all ecosystem services
- Regulating services: help regulate and maintain the environment and natural phenomena
- Provisioning services and goods- the material benefits we gain from an ecosystem e.g. food, water, wood, medicine
- Cultural services- nonmaterial benefits people gain from ecosystems such as cognitive development, spiritual enrichment, reflection and recreation.
Why is the ecosystem unable to support many tertiary animals?
Energy flow through the ecosystem results in a lot of energy lost at each stage or transfer e.g. primary to secondary consumers etc.
What first highlighted the value of ecosystems and their services?
The global Millennium Ecosystem Assessment initiative which was launched by the united nations in 2000. It revealed that 2/3 of the earths ecosystems were in decline or threatened.
What is meant by pattern in evolutionary sense?
Pattern is the change we see in the fossil record overtime. It is like the phenotypic change in species over time.
Why is understanding pattern important?
It allows us to infer evolutionary relationships between fossil organisms and living descendants, and helps us reconstruct evolutionary change and figure out who is related to who.
What are the early theories of evolution?
Scalae naturae: All organisms are on a steady march towards perfection, starting with slime moulds at the bottom and humans at the top
Theistic evolution: Devine being created all beings along time ago. It can also be the belief that a god drives beneficial mutations
Orthogenesis: Organisms evolve in a straight line, selection pressure towards a specific goal.
What are the more recent theories of evolution and how do they have some truth in them?
Catastrophism: theorises evolution is driven by catastrophic events- catastrophic events are significant to evolution
Lamarkism: Organisms acquire traits through their lifetime that are heritable- epigenetics are somewhat similar to this
Mutationalism is the theory that species emerge in large jumps due to mutations- mutations do cause evolution but much more slowly
What is Darwin’s thinking and theory of evolution
All species are fertile enough that if all offspring survived and reproduced, the population size would grow, but populations stay relatively stable. Resource availability is limited and tends to stay relatively stable, so there must be a fight for survival. There is a variety of traits within a species that are heritable. Species with more advantageous traits are more likely to survive and reproduce passing on these traits to the offspring. These variations accumulate over time to form new species.
How did Mendel contribute to modern synthesis
Mendel came up with two key rules of inheritance.
1. Law of segregation: genetic material is split into gametes
2. Law of independent assortment: genetic material is a mix of maternal and paternal DNA
What are the different types of selection?
Stabilizing selection selects against both extremes and favors the mean
Directional selection selects for one of the extreme and against the other
Disruptive selection selects against the mean
What contributes to the phenotype of an individual and how is this beneficial?
There are genetic and environmental aspects to every trait. This allows organisms to adapt to their environment. This is known as phenotype plasticity: variation across the same genetic background. Only the genetic aspect is heritable.
What is the heritability of a trait and how can this be calculated?
The heritability of a trait is how much of that trait is due to genetic factors- how much of the trait can be inherited. It is the ratio of genetic variation over phenotypic variation (h2= Vg/Vp). A good way to measure heritability is to plot the mean value of a parental pair trait to the mean value of a offspring trait on a graph and measure gradient.
What is the breeders equation?
The breeders equation is used to determine the change in phenotypes between generations by taking how much phenotypic change there has been due to selection and multiplying it by how much of that change will be heritable.
R= h2S
If the heritability is one, then the change in phenotype will be perfectly inherited.
What is sexual selection?
Genes that improve chances of finding a mate are selected for and more likely to be passed onto the next generation.
What is the difference between intrasexual selection and intersexual selection?
Intrasexual selection is when there is competition within the same species for access to mates (male dominance)
Intersexual selection is where members of one species choose members of the opposite sex based on traits that show fitness.
The sex that chooses the mate may be to do with investment they make to offspring
How does sexual selection affect variability in reproductive success?
The species that is being selected has much more variation in reproductive success. e.g. females selecting males based on traits: most females have similar reproductive success but a lot of variation in the males.
What is phylogeny?
The evolutionary history of a species of group, often represented by a phylogenic tree
What is comparative anatomy?
Comparing similarities in the anatomical structures of organisms, organisms that look similar are likely to have a common ancestor.
Why is the fossil record so important?
The fossil record shows how species have evolved and how different species are related to each other. Fossil evidence can be used to bridge the gap between different species.
What is the use of molecular clocks and how do they work?
Molecular clocks are used to estimate how long ago species diverged. Regions of DNA evolve at a fairly constant rate so by measuring the differences in the genetic sequences of species, how long ago they diverged can be estimated.
E.g. how many mutations happen per generation and how long generation time is.
Where do the different types of DNA get inherited from?
Children get 50% of their nuclear DNA from each parent, 100% of their mitochondrial DNA from the mother and 100% of their y chromosomal DNA from their father.
How recently did humans and Neanderthals’ co-exist?
30000 y/a
Where did all the similar human species live 100000 years ago and 25000 years ago
Homo-sapiens: africa
Homo-neanderthalensis: europe
Home-erectus: asia
25000 homo-sapiens were the only species on the planet.
Why do we have 3-4% of neanderthal DNA in our genome?
Humans and neanderthals genetically split around 700000 years ago, and were different species living in different areas 370000 years ago. Modern humans then spread from africa and reached europe 40000 years ago where they met neanderthals again and reproduced.
