mocks cramming - topic 3 - Biodiversity and Conservation Flashcards
Types of biodiversity (3)
- genetic diversity
- species diversity
- habitat diversity
Simpsons Diversity Index
D = N(N-1) / n(n-1) + n(n-1)… etc
N is the total number of organisms of all species found.
n is the number of individuals of a particular species.
Simpson Diversity Index for the meadow:
D = 150(149) / 50(49) + 50(49) + 50(49)
D = 22,350 / 2,450 + 2,450 + 2,450
D = 22,350 / 7,350
D = 3.04
Genetic diversity
refers to the variation of genes within the genetic pool of a populationof a species; it is the means by which that population can adapt to change. If there is a high level of genetic diversity there is a higher probability that some individuals within the population possess the genes that are best suited to any changes in the
environment.
(eg. range of domestic cats)
Habitat diversity benefits
High habitat diversity gives different areas for populations of species to spread into. Separation prompts greater variations in the
gene pools (genetic diversity…) and results in higher species diversity.
genetic diversity benefits
increases species adaptability and can lead to speciation and thus higher species diversity.
higher probability that some individuals within the population possess the genes that are best suited to any changes in the
environment.
species diversity benefits
High species diversity of plants = higher habitat diversity.
heightens resilience to disturbance in overall ecosystem probably
How did the reintroduction of wolves in Yellowstone National Park contribute to the overall biodiversity of the ecosystem?
Over time, the reintroduced wolf population in Yellowstone thrived, leading to positive ecological changes. The wolves’ predation on elk had a cascading effect on the ecosystem, resulting in reduced grazing pressure on vegetation and subsequent recovery of plant communities. This, in turn, benefited a range of other species, including birds, beavers, and even fish.
Speciation steps (5)
Geographic Isolation: The initial step in speciation is the separation of a population into distinct groups, often due to geographic barriers such as mountains, rivers, or changes in habitat. This isolation prevents gene flow between the separated populations.
Genetic Divergence: With limited or no gene flow between the isolated populations, each group starts to accumulate genetic differences over generations. Various factors, such as genetic mutations and genetic drift, contribute to these genetic variations.
Reproductive Isolation: Over time, the genetic divergence between the isolated populations may result in reproductive barriers. These barriers prevent individuals from successfully interbreeding or producing fertile offspring when they come into contact again. Reproductive isolation can be due to differences in mating behaviors, physical incompatibilities, or changes in reproductive timing.
Adaptation and Natural Selection: As the isolated populations experience different selective pressures in their respective environments, they adapt to their specific ecological niches. Natural selection acts on the genetic variations present in each population, promoting traits that enhance their survival and reproductive success in their respective habitats.
**Speciation: **Once reproductive isolation is established and significant genetic and phenotypic differences have accumulated between the two populations, they are considered distinct species. They can no longer interbreed and produce viable, fertile offspring.
Natural Selection
The mechanism where advantageous traits become more common in a population due to their impact on survival and reproduction.
mutations
A mutation is a change in the DNA (determines everything
about an individual) and it can be a single change or
multiple changes. Evolution is usually the result of an
accumulation of several mutations.
Biogeographical distribution / divergent evolution (finches)
It was the biogeographical distribution of organisms that first prompted Darwin and Wallace come up with the theory of evolution. In particular, they looked at the adaptive radiation of the finches on the Galapagos Islands. They noted that a single species would spread into various niches, adapt to different
conditions and evolve into a new species. This is also an example of divergent evolution.
endemic species
is unique to a particular location and not found elsewhere.
6th mass extinction
caused by the actions of humans and may be far greater in both extent and rate. humans are pushing more animals to extinction faster than happened in any of the previous mass extinctions.
Disruption of Arctic Food Web:
Polar bears are apex predators in the Arctic food web, meaning they are at the top of the food chain. They primarily feed on seals, helping to control their populations. If polar bears disappear, the seal population could increase, leading to imbalances in the ecosystem and potential overconsumption of other Arctic species they prey upon
Humans Impact on Diversity (5 causes)
bad
- Over-exploitation of resources
- climate change
- Habitat fragmentation,
degradation and loss - Invasive species
- Pollution
Dodo case study
was endemic to the island of
Mauritius in the Indian Ocean
Dutch sailors arrived in 1640s
bad things included:
- Hunting of the bird by humans for meat.
- Introduction of animals to the island by humans, such as dogs, monkeys, pigs, and rats, which attacked the nests and ate the eggs and chicks.
- Human exploitation of forest resources, destroying the
forest habitat.
extinct :(
biological hotspots
Proposed in 1988 by British
environmentalist Norman Myers
these sites must have
- a high level of endemic species
- be under threat
allows conservation efforts to be focused in areas where it can protect the highest numbers of species
Reasons for Conservation
- ecosystem sustainability
- sustainable resource management
- preservation of cultural heritage
Conservation helps protect natural habitats and species that can act as buffers against the impacts of climate change.
Healthy ecosystems, such as wetlands and forests, can mitigate the impact of natural disasters like floods and landslides.
Utilitarian values include:
Direct use that can be sub-divided into:
Consumptive use, such as goods that are harvested such as food, timber, medicines.
Non-consumptive use, such as aesthetic, recreational and educational use.
Ecological services, such as carbon sink, production of oxygen, water filtration, waste assimilation, nutrient recycling, flood control.
Option value is the potential value in the future, for instance from discoveries of new medicines.
Bequest value, the passing of benefits to future generations.
Non-utilitarian values include:
Intrinsic value, the right of a species to exist (biorights), an ethical based reason also supported by deep ecologist.
Existence value, knowing the species exist. For example, many of us may never visit the Amazon rainforest but we gain satisfaction from knowing it exists.
The Millennium Ecosystem Assessment (2005) explicitly linked biodiversity to human well-being. The report categorized the values of biodiversity into the following groups: (4)
- Provision value e.g. food, freshwater, wood, fuel.
- Regulating value e.g. climate change, flood regulation, water purification.
- Supporting value e.g. nutrient cycling, soil formation, primary production.
- Cultural value e.g. aesthetic, spiritual, educational and recreational uses.
flagship species
They are typically charismatic and large animals. Action taken to improve the survival of flagship
species can also benefit the whole ecosystem.
eg. bengal tiger
Umbrella species:
often large species requiring
large habitat areas. Protecting the habitat of this species
also protects the habits of other species.
(eg. The Giant panda
is both a flagship species and an umbrella species.)
Keystone species
interact through the food
web with other species in the community and if lost could
lead to the demise of other species. Conserving a keystone
species helps to protect the integrity of the community.
Eg. beavers, starfish
Approaches to conservation
three basic approaches:
- species-based,
- habitat based
- a mixture of
both
In-situ (original place) conservation
the reasons for species loss
need to be addressed.
eg. Following the commercial banning of humpback whales by the
International Whaling Commission in 1966, species numbers in
the wild have increased and are no longer considered at threat by
the IUCN Red List.
Ex-situ conservation
This usually involves removal of the species from their natural habitat and placing them into captivity
(e.g. zoo or aquarium) as part of a breeding programme to increase numbers.
Samples of plant species under threat may be removed from their habitat and placed in botanical gardens or herbariums.
convergent evolution
where similar structures have evolved independently in different organisms without the presence of a common ancestor
eg. the Sperm whale and copepods have both evolved the same buoyancy control but they are unrelated.
