3.1: Biodiversity And Evolution Flashcards
(18 cards)
What is biodiversity?
The variety of life on earth and the essential interdependence of all living things
-> study of all the variation that exists within all forms of life
-> very important -> increase resilience/resistance to change
Ecosystems + species + genetics
What are the 3 levels biodiversity can be assessed at?
Number and range of different ecosystems and habitats
Number of species and their relative abundance
Genetic variation within each species
What is genetic diversity?
The range of genetic material present in a gene pool/population of a species
Individuals of same species same set of gene -> variety of different forms
- allows genetic diversity between populations
Genetic diversity in a population -> help adapt/survive to changes
- abiotic/biotic factors
What is habitat diversity?
The number of different habitats per unit area that a particular ecosystem or biome contains
Many habitats -> high biodiversity
Ex: coral reefs -> lots of microhabitats and niches
One/two habitats -> low biodiversity
Ex: sandy deserts -> constant conditions throughout
+ habitat diversity -> increase in other two types of diversity
What is species diversity?
A variety of species in a given area, habitat or region
Number of species + number of individuals in each species
Variety differs from habitat -> habitat:
Ex: rainforest (+++) on one end and polar ice caps (- - -) on the other
What are the two variables that contribute to species diversity?
Species richness (number of species)
Species evenness (relative proportions)
+ richness and + evenness = + diversity
-> more stable/resilient to environmental changes
Ex: pine forest in Florida -> ecosystem dominated by 1/2 tree species
- pathogen take out one of two -> ecosystem could collapse
How does evolution affect biodiversity?
Evolution: cumulative change in the heritable characteristics of a population or species
- over generation
- gene controlling factors
- not an individual
Biodiversity ARISES from evolutionary processes
What is natural selection?
The mechanism that drives evolutionary change:
The process by which organisms that are better adapted to their environment survive, reproduce, and pass on their advantageous traits -> advantageous characteristics increase in frequency
- discovered by Charles Darwin
- occurs over billions of years
Result of natural selection -> biodiversity
How does natural selection affect evolution?
Individuals best adapted to survive -> most likely to reproduce => due to natural selection
Individuals in a species show range of variation (genetic diversity) ->
Organisms produce more offspring than environment can support ->
Competition (food, space, etc.) = STRUGGLE FOR SURVIVAL ->
Individuals most suited have higher chance of survival + reproduce ->
Genes resulting in these traits passed onto offspring at higher rate ->
Next generation will generally be better adapted
(NOTE: survival is not guaranteed and selection pressures can change over time)
Simplified sequence of evolution:
Reproduction -> struggle for survival -> natural selection -> population evolve to be adpated to the environment
What are different things organisms have to compete for?
Food: best at finding/reaching/catching/opening/digesting
Predation: best at catching/fighting/avoiding escaping
Parasitism/disease: best at invading/avoiding/removing/tolerating
Mates: best at attracting/fighting/selecting/fertilizing/providing for
Space: living space/nesting space/reproductive space
What is speciation?
The generation of new species through evolution
- occurs when populations are isolated and adapt to their environments in different ways
- different path of selection -> some alleles over others in one population but not in another
Over time populations so different -> no longer interbreed to produce fertile offspring -> separate species
What are the steps of speciation?
- Geographical isolation (ex: river, mountains, continent drift, migration)
- Mutations and natural selection -> two subspecies
- Reproductive isolation produces two species -> reproductive organs no longer fit
What is the difference between species richness and species diversity?
Species diversity -> more informative measurement than species richness
- conservationist favor species diversity -> takes into account richness and evenness
Ex: area 1 and 2 has 4 tree species
BUT area 2 is dominated by one species
- both areas same richness, but very different species diversity
What is simpson’s diversity index?
Biological communities -> compared using diversity indices
- mathematical tools used to quantify species diversity in a community
- provide measure of species diversity and abundance
-> used to compare different communities or track change in diversity/time
Important to repeat investigations over time to see if:
Biodiversity in in/decreasing (Pollution? Eutrophication? Colonization?)
D= N(N-1)/∑n(n-1)
Where:
D = diversity index
N = total of organisms of all species
n = number of organisms of a single species
Why is biodiversity management important?
Ecosystem stability:
Biodiversity maintain ecosystem resilience to changes
Medicine and pharmaceuticals:
Many medicines -> derive from biodiversity
Potential treatment for various diseases
Cultural and spiritual significance:
Biodiversity -> culture/spiritual important
Preserving traditional knowledge
Economic benefits:
Biodiversity -> tourism, livelihoods support local economies
Climate regulation:
Ecosystem -> help mitigate climate change (sequester CO2)
Pollination and food security:
Pollinators essential for crop pollination/food production
How is knowledge of biodiversity gathered?
Effective biodiversity management -> comprehensive understanding at global and regional levels
GLOBAL:
International organizations:
IUCN, WWF -> gather data globally
Ex: IUCN red list
REGIONAL:
National and local agencies:
Government-funded agencies
Ex: Natural England in UK -> collect data on local species/habitats
-> surveys on bird populations to monitor their status
Citizen science:
Public participation in scientific research
Volunteers collect data on local wildlife -> used by scientists
Ex: Big Butterfly Count in UK
Voluntary organization:
NGOs like The Wildlife Trusts in the UK work on local biodiversity projects
Ex: long-term hedgehog monitoring program
How is knowledge of biodiversity gathered through training for data collection?
Indigenous people:
Indigenous communities usually possess detailed traditional knowledge of local ecosystems
-> training help integrate their knowledge + scientific methods
Ex: indigenous rangers in Australia -> trained to monitor+protect native species
Parabiologist:
Local people trained to assist in biological research
-> bridge gap between local communities and scientific researchers
-> may be used to gather information for use in conservation management
What are some biodiversity management strategies?
Creation of protected areas:
Creating parks, reserves and conservation areas
Ex: establishment of marine protected areas to protect coral reefs
Habitat restoration:
Restoring degraded ecosystem to natural state
Ex: rewilding projects -> restoration of ecosystems by reintroducing native species to original habitats
Sustainable practices:
Encouraging sustainable agriculture, forestry, fishing
Ex: certification scheme (ex: Fair Trade) promote sustainable farming practices
