genomes to ecosystems Flashcards
what is an ecosystem?
a community of organisms and their physical environment interacting together. both biotic and abiotic factors and their interactions.
what are the four basic services carried out by ecosystems?
- regulating
- supporting
- cultural
- provisioning
describe the symbiotic relationship between coral and zooxannthellae dinoflagellate algae
-corals live in shallow, warm water, nutrient poor waters
-corals are colonial cnidarians and feed on zooplankton
-they have evolved faculative endosymbiosis with zooxanthellae dinoflagellate algae to provide vital additional nutrients
-90% of algal nutrients are used by coral, including two essential amino acids
-algae get a nutrient stable refuge, coral gets food
-evidence of genomic co-evolution and co-adaption
-zooxanthellae clades are specific to particular coral families
what is a symbiotic relationship?
one where the two organisms depend on one another to survive
e.g. coral and zooxanthakkkae dinoflagellate algae
what is coral bleaching?
-under stressful conditions, algae produce clouds of reactive oxygen species
-ROS cause oxidative damage, DNA mutations, cell death
-the coral boots them out
what causes coral bleaching?
CO2 emisions and climate change: sea surface temperature increases
Ozone depletion: increased solar irradiance
Deforestation: silt deposition (anoxia)
Overfishing: prey overabundance (anoxia)
coral is highly sensitive to environment stressor (many are caused by man)
*silt is a fine sediment which settles at the bottom of a body of water
what is anoxia in terms of coral reef?
when there is no dissolved oxygen in the water
what services to coral reefs provide?
- habitat for fisheries
- biodiversity
- tourism
- coastal protection
- carbon sinks
- drug/medicine discovery
*monetising ecosystem services is an important means for ecologists and conservation biologists to engage with government and industry
what is an ecosystem?
a community of organisms and their physical environment interacting together. both biotic (living) and abiotic (non-living) factors.
what are the four basic functions carried out by ecosystems?
energy transfer
nutrient cycling
water cycling
CO2 cycling
what are ecosystem processes?
nutrient uptake/release
decomposition
water uptake/evapotranspiration
photosynthesis
herbivory
pollination
predation/paracitism/pathogen attack
how is the concept of ecosystem goods and services linked to the healthy functioning of ecosystems?
Ecosystem services are the benefits provided to humans through the transformations of resources (or environmental assets, including land, water, vegetation and atmosphere) into a flow of essential goods and services e.g. clean air, water, and food (
what are detritivores?
organisms that consume dead and decaying organic matter
what are the two ecosystem components? give examples.
abiotic: sunlight, temperature, precipitation, substrate type, soil/water, chemistry
biotic: primary producers, herbivores, carnivores, omnivores, detritivores
what are ecosystem functions?
the primary ecosystem processes of capturing, storing and transferring energy, carbon dioxide, nutrients and water.
refers to the capacity of ecosystems to carry out the primary ecosystem processes of capturing, storing, and transferring energy, CO2, nutrients and water.
describe the transformations of energy in an ecosystem.
-Primary production: energy from the sun is captured by the process of photosynthesis. CO2 is combined with H2 (derived from the splitting of water molecules) to produce carbohydrates (CHO). Energy is stored in high energy bonds of ATP (adenosine triphosphate).
-Herbivores obtain their energy by consuming plants/plant products
-Carnivores eat herbivores
-Detritivores consume droppings and carcasses
energy flows from trophic level to trophic level via the food chain, energy is lost at each transfer.
what is a trophic level?
composed of organisms that make a living in the same way; that is they are all primary producers (plants), primary consumers (herbivores), or secondary consumers (carnivores).
Dead tissue and waste products are produced at all levels. Scavengers, detritivores and decomposers collectively account for the use of all such ‘waste’. Consumers of carcasses and fallen leaves may be other animals, such as crows/beetles, but ultimately it is the microbes that finish the job of decomposition.
*energy is lost between each trophic level
what causes the amount of primary production to vary?
differences in the amount of solar radiation and the availability of nutrients and water.
why are there fewer carnivores than herbivores in an ecosystem?
because energy is lost at each trophic level in the food chain
what are ecosystem goods and services?
the Earth’s ecosystems provide humanity with a wide range of benefits known as ‘ecosystem goods and services’
- in the past, societies often failed to take account of the importance of ecosystems, they were frequently regarded as public property and were consequently undervalued
what is the millennium ecosystem assessment?
in 2000, the united nations launched a global millennium ecosystem assessment initiative (MA)
2/3 of Earth’s ecosystem services are in decline/threatened
what are the four types of ecosystem goods and services?
supporting services; such as the nutrient cycle, soil formation and habitat provision for biodiversity, forming the basis for the other three types of services.
regulating services; benefits obtained through moderation or control of ecosystem processes, including regulation of local climate, air, or soil quality; carbon sequestration; flood, erosion, or disease control; and pollination.
provisioning services/goods; obtained from ecosystems.
cultural services; nonmaterial benefits people obtain from ecosystems through spiritual enrichment, cognitive development, reflection, recreation, and aesthetic experiences
what are supporting ecosystem services?
processes that are necessary for the production of all other ecosystem services, nutrient dispersal and cycling, seed dispersal, primary production
what are regulating ecosystem services?
benefits obtained from ecosystem processes that help regulate natural phenomena
benefits obtained through moderation or control of ecosystem processes, including regulation of local climate, air, or soil quality; carbon sequestration; flood, erosion, or disease control; and pollination.
what are cultural ecosystem services?
nonmaterial benefits people obtain from ecosystems through spiritual enrichment, cognitive development, reflection, recreation, and aesthetic experiences
-heritage values, cultural identity, spiritual services (sacred, religious), inspiration, aesthetic appreciation, recreation and tourism, scientific discovery
what are provisioning/goods ecosystem services?
obtained from ecosystems.
goods; food, crops, wild foods, spices, water, minerals, energy (hydropower, biomass fuels), raw materials, genetic resources, medicinal resources, ornamental resources.
e.g. substances from plant species in more the 50% of prescription medicines;»_space;2000 plant species in industry (paper, furniture, textiles, paints)
explain supporting vs regulating services
supporting services; services that are necessary for the production of all other ecosystem services
soil formation, photosynthesis, nutrient cycling, biomass production, water cycling, provisioning of habitat
regulating services; benefits obtained from the regulation of ecosystem processes
carbon sequestrations, water recycling, water cleansing, regulation of climate, regulation of the water cycle, regulation of human diseases
what is evolution?
the change in the characteristics of a species over several generations and relies on the process of natural selection
what is pattern in terms of evolution?
-pattern is the change we see in the fossil record through time
-infer evolutionary relationships between different fossil organisms and their living descendants
-assumption that all organisms, extinct or extant are in some way related
-infer ancestry via homology
what does homology mean?
the similarity in the structure, physiology, or development of different species due to a shared evolutionary ancestor
what is the process which drives evolutionary change?
natural selection.
summarise natural selection.
every species is fertile enough that if all offspring survived to reproduce, the population would grow; despite fluctuations, populations remain roughly the same size. resources such as food are limited and are relatively stable over time. (a 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 effected process results in populations changing to adapt to their environments and ultimately, these variations accumulate over time to form new species.
what are mendel’s laws
law of dominance and uniformity
law of segregation
law of independent assortment
what does the law of dominance state?
‘when parents with pure, contrasting traits are crossed together, only one form of the trait appears in the next generation. the hybrid offspring will exhibit only one dominant trait in the phenotype.’
what is the law of segregation?
only one of the two copies present in an organism is distributed to each gamete (egg/sperm) and the allocation of the gene copies is random.
what is the law of independent assortment?
the alleles of two (or more) different genes get sorted into gametes independently of one another
how does selection act on phenotypes? (3types of selection)
selection type 1: stabilising/purifying
- selection against extreme trait values, phenotypic variation lost from population, mean trait value stays constant
selection type 2: directional selection
-mean trait value moves in response to the direction and intensity of the selection
selection type 3: disruptive selection
-selection against mean trait, the result is a multimodel trait distribution, both extreme traits are favoured in an environment
what is the equation for the heritability of any given trait?
h2=VG/VP
*heritability of any given trait is the ratio of the genetic variation to total phenotypic variation
VG = varitation in genotype
VP = variation in phenotype
what is phenotypic placticity?
the ability of individual genotypes to produce different phenotypes when exposed to different environmental conditions.
what is the breeders equation?
R=h2S
R; evolutionary response
h2; heritability
S; selection differential
the greater the heritability of a trait, the faster a species can respond to selective pressure
what is sexual selection? (and what are the types?)
darwin noted that some characteristics in sexually dimorphic species could not readily be explained by natural selection.
intrasexual selection; competition between members of the same sex (usually males) for access to mates
intersexual selection; where members of one sex (usually females) choose members of the opposite sex
**traits that increase the individuals reproductive success even at expense of their survival
e.g. a peacocks tail
what is phylogeny?
a diagram that depicts the lines of evolutionary decent of different species, organisms, or genes from a common ancestor
what is morphology?
the science of the form and structure of organisms
are humans more/less genetically varied than chimps?
less. there are about 300,000 chimps in the world and 7 billion humans but chimps are more genetically variable than humans!
what percentage of DNA is shred with a sibling?
average 50% but ranges 38%-62%.
this means that fifth cousins (shared great great great great grandparent) can share none of the same DNA with you 0%-0.2%;0.05% average.
what is the founder effect?
the reduction in genomic variability that occurs when a small group of individuals become separated from a larger population
founder effect vs bottleneck effect
(genetic drift)
bottleneck effect; where disaster reduces population size
founder effect; when a small group starts a new population
*both result in less genetic variation
what is genetic drift?
the change in frequency of an existing gene variant in the population due to random chance- may cause gene variants to disappear completely, reducing genetic variation or make rare alleles become much more frequent/fixed.
what is a species?
a group of organisms which can reproduce with one another and can produce fertile offspring
what is speciation?
how a new kind of plant/animal species is created; occurs when a group within a species separated from other members of its species and develops its own unique characteristics
(allopatric and sympatric speciation)
what is allopatric speciation?
-external barrier separated populations
-populations diverge genetically
or
-(founder effect) small population becomes isolated
-rapid evolution due to non-random sample of genes, different environment, etc
what is sympatric speciation?
-no geographic barrier
-populations may differ in habitat, behaviour, adaption
-assortative mating may lead to genetic divergence