A4.2 Conservation of biodiversity Flashcards
What is biodiversity?
Biodiversity or biological diversity is the variety of living organisms (life) on Earth, or in a specific area, including plants, animals and microorganisms.
What are the three levels of biodiversity?
Biodiversity exists at three levels:
- genetic diversity
- species diversity
- ecosystem diversity.
What is genetic diversity?
Genes are basic units of inheritance. Mutations result in slightly diff versions of same genes. These versions = alleles. Genetic diversity is the variation that exists in genes of a population i.e. diversity seen in the genes (alleles) within a pop of a species.
Why is genetic diversity important?
A higher genetic variation increases probability of alleles in gene pool that allow an organism to adapt to changing environmental conditions. E.g. think of a scenario when a pop with a high genetic variation is exposed to adverse climatic conditions. Due to genetic variation, there are greater chances that genes that enable organisms to adapt to climatic conditions already exist in pop. Due to differential reproduction, these genes are transmitted from one generation to another making sure species survives. Thus, genetic diversity acts as raw material for evolution.
What is an example where genetic diversity has lead to evolution?
E.g. evolution of DDT-resistant mosquitoes. DDT = insecticide that is often used to kill mosquitoes. When DDT was first sprayed, there was a decrease in local mosquito pop. However, a small fraction of pop survived due to presence of DDT-resistance genes – a result of genetic variation. These resistant mosquitoes reproduced, passing on gene to their offspring & eventually resulting in a pop of DDT-resistant mosquitoes
What are the consequences of a low genetic diversity?
If genetic diversity is low – as often seen in endangered species, chances of species surviving is lower when environmental conditions change.
What is species diversity?
Species diversity in very simple terms = variety of species seen in a particular habitat. Species diversity differs according to habitat. It’s number & types of organisms that existed during a specific amount of time.
What two factors does species diversity depend on?
- Species richness or number of diff species in the area. E.g. Great Barrier Reef or Amazon Rainforest has a greater number of species compared with Antarctic continent or salt pans.
- Species evenness or relative abundance of diff species in given area. If numbers of individuals of each species (species abundance) are similar across diff species, species evenness is high. Conversely, if numbers of individuals of each species vary, species evenness is low
What is an ecosystem?
An ecosystem is defined as community of organisms & their interaction with abiotic environment. Ecosystems vary in size
What is ecosystem diversity?
Ecosystem diversity = variety of ecosystems, both terrestrial & aquatic, found in a given geographical area. E.g. rainforest has many ecosystems within it, including; canopy, formed of overlapping branches & leaves of tall trees, understory that lies several metres below canopy & forest floor. Ecosystem diversity is a function of community & habitat diversity.
Why is ecosystem diversity important?
It’s important for determining total biodiversity, but ecosystem diversity is harder to measure. This is bc boundaries of many ecosystems aren’t fixed & tend to gradually change from one type to another.
Why is diversity at all three levels important?
Diversity at all levels is important. In fact, these levels cannot be separated. E.g. high diversity in types of ecosystems would indicate a high diversity in types of species seen. Changes in one level often cause changes in other levels.
How do we know different organisms have lived on Earth during different periods of times?
Strong evidence for this comes from fossils; e.g. preserved remains of organisms such as bones, teeth or leaves.
Why is only a small percentage of animals that lived on earth fossilized? And what has that small percentage informed us?
Yet, a very small percentage of animals that lived on Earth became fossils – probably due to fact that conditions necessary for fossils to form rarely occur. Even though fossil records are incomplete & often patchy, they are indicators of diversity of species that existed in past & are used to understand changes in biodiversity over geological timelines. These studies in turn have led to current view that number of species seen on Earth today is more varied in number & complexity than at any point in past.
What is the estimated number of species in existence?
Scientists estimate that there are approximately 8.7 mn species of plants & animals in existence, of which only 1.2 mn species have been identified & categorised. This means that a huge 86% of species still remain to be discovered! This estimate doesn’t take into account prokaryotes.
Why is cataloguing species taking time? And why is this a problem?
There are many reasons why it’s taking time to catalogue species. Part of problem is that many living organisms live in inaccessible places or even inside other organisms. However, lack of knowledge of true biodiversity has consequences as each species not only has its own intrinsic value but could also be an answer to problems. Current rate of biodiversity loss means that we are losing species faster than we are identifying them.
What extinction are we currently experiencing?
We are currently experiencing the sixth mass extinction. There has been an alarming decline in plant & animal species. Extinction rates are historically higher than ever, with predictions of 10% to 50% species loss within next century, a relatively small amount of time on evolutionary timelines. Many species, like dodos, have become extinct, while many others are on brink of extinction.
What is different about are current mass extinction compared to the other?
However, unlike previous mass extinctions, sixth mass extinction is a result of human activity. When human activity leads to extinction of species it’s = anthropogenic species extinction.
What anthropogenic activity caused the extinction of the dodo bird?
The sailors who came to island of Mauritius found dodos easy to hunt. Birds were slow, couldn’t fly & had no natural predators. Overexploitation along with destruction of their natural habitat caused dodos to become extinct in a relatively short period of time.
What anthropogenic activities have caused extinction?
Anthropogenic species extinction is caused by:
- overexploitation due to overhunting or overharvesting
- habitat loss due to human activity
- introduction of invasive or alien species outcompeting native species
- habitat degradation due to pollution
- climate change.
What are megafauna? And caused their extinction?
Megafauna literally means large animals. Moas, mammoths & giant kangaroos = examples of extinct megafauna. There has been a lot of debate around what led to the extinction of these megafauna, with causes ranging from volcanic eruptions to diseases to climate change.
What are Moas? Where were they from? What were their characteristics?
Moas were flightless birds endemic to islands of New Zealand. One of nine species that became extinct, the North Island giant moas (Dinornis novaezealandiae) were tall, slender birds with long, shaggy, hair-like feathers. These herbivorous birds thrived for millions of years, yet about 600 years ago, they became extinct
What was the cause of the moas’ extinction?
Recent fossil studies with analysis of bone DNA indicate that extinction of these birds was caused by human activity. For millions of years islands of New Zealand surrounded by water remained isolated. When island was colonised by Polynesians in t13th century, large birds became a source of food for newly arrived humans. Birds who had never seen terrestrial mammals before people arrived, stood no chance. Birds of all ages & the eggs were eaten. Within a short span of 100 years, birds were hunted to extinction by a relatively small pop of approx 2,500 individuals. Apart from overexploitation, rats which ate eggs & chicks, & diseases brought by humans could also have been factors that contributed to extinction of moas.
What are Caribbean monk seals? Where were they found?
The Caribbean monk seals (Neomonachus tropicalis) were marine mammals found in warm waters of Caribbean Sea & western Atlantic Ocean
When was the first sighting of the Carribbean monk seal? And what did it lead to?
The first sighting of these mammals is recorded in accounts of Christopher Columbus in 1494. Record goes on to state how sailors killed eight seals resting on beach. An account from 17th century describes how fishermen killed hundreds of seals every night to fuel oil lamps & grease machinery. In less than 600 years, Caribbean monk seals had become extinct.
What caused the Carribean monk seal’s extinction?
Caribbean monk seals were relentlessly hunted in 18th & 19th centuries for their blubber & other products. Docile & non-aggressive nature of these mammals whose only natural predators were sharks, made hunting easy. In addition, overfishing in waters where they lived, meant that these animals fell short of food sources like fish & molluscs. Deprived of their natural food, many individuals in an already declining population starved to death. Last sighting of the animal was in 1952.
What were the characteristics of the splendid poison frog? Where were they located? And when were they lasted spotted?
Splendid poison frogs (Oophaga speciosa), last spotted in wild in 1992, were declared extinct in 2020. With their bright colours serving as a warning to predators of their toxicity, these small frogs were once widespread in humid forests of Panama.
What led to the decline of the once abundant species, splendid poison frog?
One of reasons attributed is a reduction in their geographic range due to activities such as logging, conversion of forests for agriculture & expansion of urban areas. Degradation & loss of their natural habitats led to a decline in pop of frogs. In addition, these frogs were trafficked as part of ‘pet’ trade. Death knell for already declining pop was outbreak of a fungal disease that had been ravaging amphibian pop in tropics.
What are the characteristics of the sixth mass extinction?
To sum up, the sixth mass extinction is under way and characterised by an extinction rate far higher than before, unprecedented in the Earth’s history. The case studies point to humans as the primary drivers of the sixth mass extinction. We need to act quickly and with intensity to slow or stop extinctions
What are the consequences of human destruction of ecosystems?
Human activity has led to decline & destruction of ecosystems. When entire ecosystems collapse, species dependent on ecosystem are driven to brink of extinction.
What are the benefits of a healthy ecosystem?
Healthy ecosystems have many benefits often referred to as ecosystem services such as:
- supplying resources, including water, food, timber and medicines
- providing basic services essential for survival, e.g. decomposition of waste, flood control, prevention of erosion, storage of carbon, climate regulation, nutrient cycling, formation of soils, water cycle, etc
What is ecosystem services?
The processes and outputs of the ecosystem that directly or indirectly benefit humans.
What is the mixed dipterocarp forest? Where is it located? What is the dominant species? And how many species does it contain?
Mixed dipterocarp forests of southeast Asia are tropical rainforests. Dominant species of trees seen in these forests belong to family Dipterocarpaceae. Deriving its name from its two-winged fruit, Dipterocarpaceae includes nearly 695 species of trees ranging in size from shrubs to towering trees that emerge from the canopy.
Why are the Dipterocarps a keystone species?
Dipterocarps are keystone species, essential for ecosystem services & functions bc:
- they support a number of other forms of life
- their leaves, fruits and seeds are food sources for many herbivores
- decomposition of their falling leaves enriches the forest floor
- their roots hold the soil
- they provide a home to many forms of life including arboreal animals, birds and epiphytic plants
- their canopy forms a large portion of the total canopy, sheltering the underlying layers from the torrential rain
- they lock up large amounts of carbon, and so help in capturing and storing atmospheric carbon dioxide and hence, help fight climate change.
Why are the Dipterocarps on the brink of extinction?
Unfortunately, these forests are under threat. Trees are highly prized for their timber & are extensively felled. This has driven many dipterocarp species to brink of extinction. Yet another threat is clearing of forests for palm oil plantations. Palm oil trees (Elaeis guineensis) were brought to southeast Asia by Europeans. Planting of palm oil trees has led to deforestation & clearing of massive tracts of rainforests. Often, to clear forests, stretches are burned down releasing carbon into atmosphere.
What is the consequences of the extinction of the Dipterocarps?
Destruction of these forests means that already endangered animals such as elephants & orangutans are losing their homes. Thus, destruction of dipterocarp forests has far-reaching consequences, not only for life they support but also for humans.
What are coral reefs? And where are they found? How many species are found there?
Coral reefs found below ocean surfaces, are one of Earth’s most diverse ecosystems & are often called rainforests of the sea. Reefs are home to nearly 25% of world’s marine species, including fish, reptiles, crustaceans & seaweeds.
Coral reefs are colonies of coral polyps, with their exoskeletons forming reefs. Symbiotic algae live in tissues of these polyps & give coral its colour
What are benefits to reefs provide?
Reefs provide a myriad of benefits:
- they sustain food webs
- provide food for people
- are sources for new medicines
- protect coastline from erosion & storms.
What threats cause the reef become endangered?
However, coral reefs are under great stress & many species of corals are endangered. Threats to reefs include:
- pollution, including nutrient-rich fertiliser runoff, hot water from power plants, rubbish, plastic, oil spills
- destructive fishing activities e.g. overfishing & use of explosives & cyanide
- loss of natural habitat due to coastal development
- unsustainable tourism where careless divers damage coral reefs
- climate change results in rising ocean temperatures & ocean acidification due to increased absorption of carbon dioxide. This in turn causes corals to expel their algae, leading to bleaching (or whitening) of coral reefs
What are the effect of bleaching of corals?
Bleaching of corals impacts their viability as it stunts their growth & leaves them vulnerable to disease. It also affects other species that depend on reefs. Although coral reefs can recover from bleaching, this takes at least 10–15 years provided environmental conditions improve
What multiple sources shows evidence for a biodiversity crisis?
- IPBES
- IUCN
- Contributions by expert scientists and citizen scientists
- The Horseshoe Count
- Biodiversity surveys
What is the IPBES? What evidence do they provide for a biodiversity crisis?
Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) = intergovernmental organisation established by UN to assess & strengthen biodiversity & ecosystem services. IPBES Global Assessment Report On Biodiversity and Ecosystem Services was released in 2019. Report has been compiled by 145 expert authors from 50 diff countries over 3 yrs & states that over a mn plant & animal species are threatened with extinction
What is the IUCN? What evidence do they provide for a biodiversity crisis?
IUCN (International Union for Conservation of Nature) looks to address challenges in conserving nature & natural resources. Work of IUCN is supported by NGOs, indigenous peoples’ organisations, volunteer scientists & experts. IUCN Red List of Threatened Species & IUCN Red List of Ecosystems are conservation tools as they seek to assess current status & inform conservation action & policy. IUCN Red List of Ecosystems is a global standard for assessing conservation status of ecosystems. Based on assessments & reassessments of species, IUCN Red List of Threatened Species has nine categories: Extinct (E), Extinct in Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD) & Not Evaluated (NE). IUCN Green Status of Species, a part of IUCN Red List, measures conservation success of species.
What is the Contributions by expert scientists and citizen scientists? What evidence do they provide for a biodiversity crisis?
Besides scientists, contributions to science can also come from general public. Citizen science refers to research conducted with help of general population who aren’t professional scientists. Research is often conceived & designed by expert scientists but executed with involvement of interested citizens. Expert scientists provide relevant information about study & methods for data collection. This is used by citizen scientists to gather data. Expert scientists then work with these data to answer their research questions.
What is the Horseshoe count? What evidence do they provide for a biodiversity crisis?
Every spring, millions of horseshoe crabs (Limulus polyphemus) migrate to Delaware Bay Shore for spawning. Fossil records indicate that this has been taking place for around 350 million years. Crab spawn is also an important food source for several migratory birds e.g. red knot. Spawn is also used as bait by fishing industry & for medical purposes. To prevent spawn overharvesting, it’s vital to undertake a census to understand number of crabs. This census data are then used to limit number of horseshoe crabs harvested for human use. Annual survey is undertaken by volunteers (citizen scientists) who are specially trained to distinguish between male & female crabs & in data recording.
What is the Biodiversity surveys? What evidence do they provide for a biodiversity crisis?
Biodiversity surveys provide valuable info to decision-makers regarding use of resources & species conservation. These usually take place within a defined area & are repeated to get a better understanding of biodiversity. Repeated surveys give info about species richness & evenness, which helps experts understand changes taking place within a community.
How has the size of the human population changed in resent years?
Human pop grew exponentially from 1-7 bn in just 200 years. In 2011, human pop = 7 bn & in November 2022, it reached 8 bn
What are the impact of the rapid increase in human population?
This rapid increase in pop has widespread implications. As pop grows, demand increases for resources including food, water & space. This increasing pressure for resources leads to overexploitation of natural resources & habitat destruction. This, in turn, adversely impacts biodiversity. Current rate of extinction is 100 to 1000 times higher than past, leading to a biodiversity crisis
What is overexploitation?
Overexploitation = overuse of natural resources at rates faster than they can be replenished
How does overexploitation, e.g. overhunting and overfishing, drive biodiversity loss?
Overhunting has led to decline & even extinction of many species. E.g. hunting of Bengal tiger for both sport & for their body parts has led to a drastic decline in their pop & extinction of three subspecies. Although these animals are now a protected species, poaching & habitat destruction further dwindles their pop. Other examples where hunting has led to species being declared threatened include elephant, bison & black rhinoceros. Today, while many countries ban hunting & have stringent policies for protecting endangered species, illegal hunting (poaching) continues.
How does destruction of habitat drive biodiversity loss?
As demand for space increases, more & more of natural habitats are lost. When habitats change drastically, species adapted to life in these habitats can no longer survive there. E.g. deforestation or clearing of forests for agriculture, damming of rivers & filling of wetlands bring irrevocable changes in habitat
What is habitat fragmentation?
Division of a large continuous habitat into smaller non-contiguous areas.
How does habitat fragmentation drive biodiversity loss?
Urbanisation encroaches on existing natural habitats & can fragment them into smaller habitats. E.g. laying of railway lines through a natural habitat, fragments area into smaller isolated patches. This, in turn, restricts animal mobility, reduces access to resources & increases the risk of extinction. One solution to this is building corridors for safe passage of animals.
How does invasive species drive biodiversity loss?
As humans colonised diff regions of Earth, they introduced new species either accidentally or deliberately to these environments. These introduced species become invasive alien species when they disrupt existing food chains, reproduce quickly, spread aggressively & outcompete endemic species.
What is an example of a plant invasive species?
Japanese knotweed, Reynoutria japonica was introduced into ponds of Europe as an ornamental plant.
What is an example of a animal invasive species?
Pet Burmese pythons were introduced into Everglades of Florida. At top of food chain, pythons feed on local species, ill-equipped to handle these new predators. This has led to a reduction in pop of local species
How does pets & diseases drive biodiversity loss?
Global transport has also introduced pests as well as diseases to native species. As consumer demand increases, live animals including goats, sheep, pigs and cows or refrigerated products are transported across world. However, this increases risk of disease transmission. In another example, global trade in amphibians has led to spreading of a fungus native to southern Asia. This in turn has caused a decline in amphibian pop across world. Spread of diseases isn’t restricted to animals. Chestnut blight in chestnut trees is caused by a fungus that was present in nursery stock exported to USA from Asia. Common pests that have been transported across globe include cockroaches & rats. While regulatory mechanisms may be in place, chances of transporting pests or their eggs & disease-causing pathogens remain high.
How does pollution drive biodiversity loss?
Pollution is one of leading causes of biodiversity loss. Pollution is intro of substances into environment that adversely affect environment. Pollution can take form of air, water & land pollution. Some causes of pollution are outlined below.
What causes acid rain and what is it’s affect on biodiversity?
Release of sulfur dioxide & nitrogen oxides (a combination of NO and NO2) from industries into air results in acid rain (Rain that becomes acidic due to air pollution, usually presence of oxides sulfur & nitrogen), which has a detrimental effect on plant & animal lives.
What happens to pollutants in the water to the biodiversity?
There is more info about how pollutants released into water often enter food chain resulting in biomagnification & affecting consumers in.
What is the effect of plastic no biodiversity?
Accumulation of plastic across habitats is one of biggest threats to biodiversity. Plastic in oceans is often ingested by seabirds & marine turtles. For threatened species like Hawaiian monk seals, plastic pollution pushes them further down path of extinction.
What is the impact of dumping rubbish on biodiversity?
Dumping of rubbish not only pollutes environment, but also can be a breeding ground for pests like flies, cockroaches, rats & mice.
What is conservation?
Conservation is protection & sustainable use of resources we have. Conservation biology looks at maintenance of biodiversity by protecting species & their ecosystems. Conservation of biodiversity requires a multi-pronged approach. Diversity in species necessitates that diff measures be taken to conserve diff species
What is in situ conservation?
On-site or in situ conservation is a way of conserving animals & plants in their natural habitats while maintaining original biodiversity of area. In situ conservation involves designating, managing & maintaining areas for protection of plant & animal species.
How are national parks and wildlife sanctuaries protected? What are nature reserves?
National parks & wildlife sanctuaries are protected terrestrial areas, while marine reserves conserve marine species & habitats. Nature reserves are areas smaller than national parks & protect a particular habitat and/or plants & animals, often declared as endangered. Human activity in these areas is strictly regulated. Responsible tourism, such as conservation safaris, in these areas helps to generate funds that contribute to their maintenance as well as increasing public awareness.
What are the benefits of in situ conservation?
In situ conservation conserves plant or animal species & their habitat. It allows species to continue living in habitat to which they are adapted, preserves their normal behaviour (in case of animal species) & prevents disruptions of food chains. Thus, in situ conservation is less disruptive & more cost-efficient
What is ex situ conservation?
Off-site or ex situ conservation, plants & animals are conserved outside their natural habitats. Ex situ conservation techniques vary & include zoos, botanical gardens & aquariums.
What happens when species numbers are too small to sustain?
In some species numbers are too small to sustain species or risk of poaching is high. In these cases, scientists establish gene banks to store ‘biodiversity’, which involve storage of germplasm (or genetic resources). These collections of living material include animals in zoos, plants in botanical gardens, seeds, sperms, eggs, pollen, DNA collections & so on.
What are seed banks?
Seed banks dehydrate & cool seeds prior to storage. One such example are seed banks created to store original wild strains of food crops such as rice in an effort to conserve their genetic info.
What are tissues banks?
Tissue banks, e.g. DNA & Tissue Bank at Kew, England, store tissue samples from plants
What is the purpose of zoos?
Zoos maintain multiple species of mammals, birds, reptiles & amphibians while botanical gardens conserve plants
What is captive breeding?
Captive breeding = conservation technique for preventing extinction of species whose populations are small, often fragmented & on verge of extinction. Animals in zoos or other places are encouraged to breed & then reintroduced into wild. However, one of major drawbacks of technique is that small pop inherently have a lower genetic diversity & thereby chances increase of passing on unfit genes.
What is an example of a successful captive breeding scheme?
One successful example of this is the Arabian oryx (Oryx leucoryx). Oryx, a type of antelope, became extinct in wild in 1972; however, antelopes existed in zoos. Captive breeding followed by ‘training’ animals for release ensured that species could be released back into wild.
What is rewilding?
Rewilding = conservation technique by which wildlife & natural processes are allowed to reclaim areas, bringing back biodiversity. In other words, habitat is restored to what it would have been if human disturbance had not happened. Rewilding happens with human intervention as plant & animal species that have disappeared from habitat are reintroduced. This, in turn, helps to rebuild ecosystems. Rewilding Institute run rewilding programmes & initiatives in this area.
What is the effect of unsustainable human activity?
Unsustainable human activity often causes a degradation of land & water. Loss could be due to erosion of soil, deforestation, salination…
What are land restoration strategies?
Land restoration strategies look at recovering & reclaiming degraded ecosystems. Studies have shown that land restoration & management with support from local communities & indigenous people yields higher results as they have a deep knowledge of land. Forests are being restored across world through programmes that engage local communities.
What is EDGE?
EDGE = Evolutionarily Distinct and Globally Endangered. EDGE of Existence was launched by Zoological Society of London in 2007 as a conservation programme to prioritise conservation of evolutionarily distinct & endangered species. Most poorly known or neglected EDGE species are often selected to prevent them from silently disappearing from face of Earth.
What are EDGE species?
The EDGE species:
- are often only surviving members of their genus or even higher taxa
- are unique in their appearance, behaviour & genetic makeup
- have a unique evolutionary history
- are globally endangered
How are species selected for EDGE?
The species are selected according to their:
- Evolutionary Distinctiveness (ED) score. ED score is determined by position of the animal on phylogenetic tree. ED scores are higher for species that are evolutionarily more distinct or have fewer closer relatives.
- Globally Endangered (GE) score. This is calculated based on IUCN Red List. More endangered species, higher GE score. E.g. critically endangered species have a higher score than endangered species or vulnerable species.
Two scores are then combined to produce EDGE score for a species. Higher than average EDGE values indicate that species is threatened with extinction.
What is Simpson’s reciprocal index?
