3.1 biodiversity Flashcards
most biodiverse ecosystems
- high rates of primary productivity, somewhat constant temps, near the equator
- e.g. tropical rainforests (land) and coral reefs (aquatic)
what is biodiversity made of?
- species diversity: calculated using Simpsion’s diversity index
- richness (# of diff species in the area) and evenness (abundance) - genetic diversity: genetic variation within a pop (makes them more resistant and resiliant to change)
- if one pop dies there are other pops unaffected and species will carry on
- low genetic diversity causes inbreeding so flaws become more common (e.g. Florida Panther w heart defects) - habitat diversity: number and range of different habitats = more niches (e.g. tropical rainforests -> complex and multi-layered structures)
factors affecting biodiversity
spacially complex, high GPP, complex and long food webs, resilient, time for colonization and organism evolvement, genetic variation, periodic disturbances which allow development
what are endemic, flagship, and keystone species
Endemic: exists in 1 spot in the world
Flagship: awarded advanced status by people
Keystone: change the structure of an ecosystem and increase resilience by existing (if removed ecosystem would likely collapse)
why quantify biodiversity
compares the diversity of communities, allows us to identify if there’s been a disturbance, identify the impact of human activity, compare similar ecosystems, figure out hotspots
who came up with the theory of evolution & key observations
Charles Darwin: theory of evolution from common descents by natural selection
Key obs: all species reproduce more than can survive so always a struggle for existence, in this struggle the less adapted die “survival of the fittest”, and this causes variation between organisms leading to evolution by natural selection
the two causes of evolution & evolution in response to env change
Mutations: change in DNA
Natural Selection: the gene variation has survival advantages
change in env = new challenges to species and this redefines what fitness is –> the ones that fit the new normal survive so beneficial features pass on
Raccoons vs Lynx example
Raccoones are omnivores who had behavioural adaptations thanks to their intelligence and varied diet
Lynx are carnivore predators that rely on large undisturbed forests so habitat destruction due to human pop reduced their pop (they also have slow reproductive rates which limits their ability to adapt quickly)
what is speciation and the different isolation causes + give an example
Over time evolution by natural selection can create new species but it requires geographical separation
- temporary isolation: pops awake at different times
- behavioral isolation: different mating ritual
e.g. Darwin’s Finches experiences geological separation and over time the beak sizes changed depending on the food available in those different areas
what are the types of plate tectonics & impact of volcanic activity?
Divergent Plate Margins = plates moving apart (allows for diversification)
Convergent Plate Margins = plates moving together creating mountains, volcanoes, etc.
Volcanic Activity = creates new habitats and niches through succession
the 3 mass extinctions
- Permian mass extiontion (The Great Dying w 96% of species gone)
- Triassic-Jurassic mass extinction (allowed dinosaurs to take over & caused by climate change)
- Sixth (Holocene) mass ext which is right now and due to humans
CASE STUDY: Peppered moth Biston betularia
birds could see dark variation easier so they got eaten more but during industrial revolution the pollution darkened the bark so light got eaten more –> then the air became less polluted & lichens came back so lighter moths were favoured again
conserving biodiversity local NGO and IGO example
Local: Pro Nature (founded 1909 Basel) –> aims to conserve biodiversity & protect landscapes
- manages around 700 nature reserves across Switzerland
International: consists of members from diff countries
e.g. The United Nations Environment Programme (UNEP)
