Biodiversity Flashcards
What is biodiversity
“ biological diversity” - the variety of life on earth
Define habitat
A place where organisms live
Define community
A collection of all populations of species in an ecosystem
What is habitat diversity
The number of different habitats per unit area that a particular ecosystem/biome contains
Habitat diversity what this might lead to an increased of?
Genetic diversity
Species diversity
What is genetic diversity
The range of genetic material present in a gene pool or population of a species
Define gene
A section of DNA that is considered the basic unit of inheritance
Define gene pool
A collection of genes and the alleles with population
Why is a high genetic diversity important
Diversity is essential for survival
Define species
A group of organisms who share similar features who can inter breed to produce fertile offspring
Define endemism + example
An organism that is found in one place but nowhere else for example (lemurs are only found in Madagascar)
Define species diversity
The variety of species within a given area, habitat or region
What are the three aspects to biodiversity
Habitat diversity
Genetic diversity
Species diversity
What can we use to work out the species diversity of community or ecosystem
The Simpsons diversity index
What is the equation for the Simpsons diversity index
D = N(N-1)/sumn(n-1)
D = diversity index
N = number of organisms total
n = number of organisms in each species
Define evenness
The relative abundance of a species (the number of individuals in a species)
Define species richness
The number of different species that are present
In the ecosystem there are five species and 20 animals. There are seven sparrows, six blackbirds, four hummingbirds, two doves and one pigeon. Calculate the species diversity of this ecosystem
7 - sparrow
6 - blackbirds
4 - hummingbirds
2 - doves
1 - pigeon
D = N(N-1)/sumn(n-1)
N(N-1) = (20)(19) = 380
sumn(n-1) = (7x6) + (6x5) + (4x3) + (2x1) + (1x0) = 86
380/86 = 4.42
What is a biodiversity hotspot
A hotspot is a region with a high-level of biodiversity that is under threat from human activities. (Around 30 or so recognised)
Name three facts about biodiversity hotspots
– generally tend to be closer to the tropics
– cover only 2.3% of our globe
– 10 are in tropical rainforest
Name five biodiversity hotspots
– Japan
– New Zealand
– Philippines
– Caribbean islands
– corner of Africa
Name one positive and five negative of a biodiversity hotspot model
Positive:
– it is a useful model
Negative:
– focuses on vascular plants and ignores animals
– does not represent species diversity
– doesn’t consider genetic diversity
– does not consider the value of services (for example water resources)
– focuses on regions where habitats have already been lost, rather than the habitats that are being lost currently
What is evolution
The gradual change in species over millions of years
What is natural selection
Nature selecting which individuals are the best adapted for survival
What is artificial selection
a process in which humans intentionally breed plants or animals to enhance desired traits
What are the seven stages in speciation
– Within a population of one species there is genetic variation
– individuals are isolated from the population to a new area with different selection pressures
– due to natural variation, some individuals will be better at surviving than others
– fitter individuals have an advantage and are more likely to survive
– these individuals reproduce and their offspring may inherit the advantageous gene
– those who do not carry these advantageous jeans maybe unlikely to survive long enough to reproduce
– this is why this process is called survival of the fittest because it leads to evolution by diversity and species overtime
Name three examples of a geological barrier
– River
– mountain range (millions of years)
– clearing in a forest
Explain the four step process of how geographic isolation can lead to 2 new species
- At the start of the process there are no geological barriers so all individuals can reproduce with each another
– mutations cause variation differences, so the species become better adapted to their environment
– natural selection occurs when the individuals best suited to their environment survive and reproduce
– when the geographical barrier is removed the populations colonise the area cannot reproduce as they are now different species
What are selection pressures
External factors that determine which individuals will do best at surviving and reproducing, i.e. new predators
Explain geographical isolation + example
When physical geographical barriers cause a population to split into two where mutations and natural selection occur to create two new species where the individuals in their species are best suited to their new environment. One example is the freshwater fish Char, which lives in lakes in Scandinavia, Switzerland and the UK. The population of this fish have been separated by the land between them meaning they can no longer interbreed
Explain behavioural isolation
Behavioural isolation refers the fact that many species perform different mating rituals and this is a common barrier between animals.
For example certain species of crickets will only meet with males that produce a particular mating song
Temporal isolation
When species that could interbreed do not because the different species breed at different different times. For example 2 different species of field crickets become sexually mature different seasons one in the spring and the other in autumn
Explain ecological/ habitat isolation
This occurs when two species that could interbreed do not because the species live in different different areas. For example in India both the lion and tiger exist and are capable of breeding however the lion lives in grasslands and the tiger lives in the forest. The species live in different habitats and will not encounter one another is isolated from the other species
Mechanical isolation
This is caused by structures that keep species isolated from one another. For example domestic dogs all belong to the same species. Dogs like the Chihuahua and the great Pyrenees hound would be unable to reproduce due to the difference in size
Chemical isolation
This is caused by chemical barriers that keep the species isolated from one another. For example some chemical barriers will only allow sperm from the correct species to fertilise the egg
Outline how the brown bear and the polar bear became two separate species
– A whole population of bears lived in one place originally
– a geological factors for example a mountain range or a river may have caused them to become isolated
– each new population has individuals that mutate for example mutation in their features
– natural selection chooses the better-adapted animal to survive and reproduce
– these animals reproduce and pass on the advantageous jeans to their offspring so that two different populations that differ so greatly that they can no longer breed even if the whole population comes together again
What is speciation
The formation of a new distinct species in the course of evolution
What is adaptive radiation
an event that causes a rapid increase in the number of species with a common ancestor, characterized by great ecological diversity
What is one example of adaptive radiation
Galapagos finches -> Some of these adaptations included size, beak shape or claw size and this was all dependent on what was available in each area
How can continental drift and plate tectonic theory contribute to adaptive radiation and speciation
As plates move they create geological barriers (for example: rivers, mountains, gorges, new islands), which can separate populations of organisms and create new species
What is the background extinction rate
It is the natural extinction rate of all species
What was the background extinction rate expected to be, and what is it currently?
It was estimated to be one species per species per year, however it is currently 100 to 1000 times more than that
Which mass extinction are we in now
We are in the sixth mass extinction, this is called the Holocene
What happens to the number of groups of organisms when there are mass extinctions
there are drastic dips in the number of families
Name three causes of mass extinction
– Overpopulation (the global population is expected to reach 9 billion by 2050))
– Global warming and climate change
– Catastrophic one-off events (astroids hitting the earth)
Name a previous mass extinction
The KT extinction (cretaceous tertiary). This is the mass extinction of the dinosaurs
Name two differences between prehistorical mass extinctions and current mass extinctions
Prehistorical disasters took over thousands or hundreds of thousands of years to take place, whereas the Holocene took over a few decades/hundreds of years. The Holocene occurs due to anthropogenic reasons, for example climate change due to the enhanced greenhouse effect, whereas prehistorical mass extinctions are not human-caused
Distinguish between the mass extinctions evident in the fossil records and extinctions within historic times (4 mark question)
Fossil record extinctions occurred over relatively long time skills, whereas present-day extinctions occurred over short time skills (decades). Inked irons within historic periods are largely attributable to human causes, for example overhunting. Past mass extinctions are linked to natural courses, for example, meteorite impacts
What is the Lincoln index + what assumption does it rely on?
The Lincoln index provides a way to measure population sizes of individual animal species which is related to capture-recapture methods.
It relies on the assumption that the proportion of marked animals in the second sample is the same as the proportion of marked to non-marked animals in a whole population
What are four limitations of the Lincoln index?
Any 4 from:
– Capturing the animal may harm them or alter its behaviour
– the mark used may harm the animal, for example, toxic paint on an animal may harm them therefore tests need to be done prior
– marks may be removed before recapture accidentally
– Marks may make individuals less or more visible to predators/mates
– the method assumes that all animals in the population are equally catchable
– this method depends on open/systems. Usually, there are no closed systems therefore readings have to be taken over shorter time to reduce changes and pop size (in an open system individuals can migrate in and out of an area skewing results)
– trapping responses may vary: individuals being trap shy (avoiding the traps), or being trapped happy (individuals may go looking for the traps as they know it is an opportunity for food)
Does trap shyness or trap happiness lead to an overestimation or underestimation
Trap shyness leads to an overestimation, whereas trap happiness leads to an underestimation
Name at least five factors that make specific animals more prone to extinction than others
Any five from:
– Natural disasters
– deforestation
– monoculture
– overfishing
– urbanisation
– altering habitat shape
– pollution (air and water)
– captivity
– antibiotics/battery farming
What three factors help to maintain biodiversity
– Inertia
– limiting factors
– stage of succession
What is inertia
The property of an organism to delay or resist change when certain factors change
What are limiting factors
If the abiotic factors are in abundance the system can survive longer even if one is reduced
Why are later stages of succession better to maintain biodiversity
Later stages are more resilient and stable than younger ecosystems because they have more niches, therefore if one organism dies, another can take its role. This is because of the complexity of ecosystems in the later stages will have more complex food webs
Name three causes of reducing biodiversity in tropical rainforest
- deforestation and logging
- ranching
- shifting cultivation
What is shifting cultivation
where the land is cleared and the vegetation burnt, crops are grown for a few years until yields decline due to decreasing fertility of the soil. The farmers then move on to a new clearing
What is ranching
Ranching involves raising livestock (e.g., cattle, sheep, goats) on large areas of land for meat, milk, wool, or other products.
Name three effects of reduced by diversity and tropical rainforest
– Production of habitats
– fewer abundance of ecological niches
– lower rates of biomass and photosynthesis
Outline the ways in which natural selection leads to biodiversity (4)
– natural selection occurs when a population of individuals has adapted better to selection pressures
– they are more likely to reproduce and pass on advantageous alleles to their offspring
– this will increase allele frequency and genetic diversity
– more niches will be created and overall a new and better-adapted species
Explain the role that plate activity has in the diversity of an ecosystem (3)
– When plates converge, this forms new land. this creates natural barriers such as mountain ranges
– another example is when plates diverge creating gorgeous or river forms
– there are now new selection pressures in different environments
– organisms that have adapted successfully pass on their alleles, increasing genes diversity and speciation
Name 3 factors that destroy biodiversity
any 3 from:
- natural hazards
- pollution
- habitat fragmentation
- the spread of disease
- alien species invasion
- modern agricultural practices
- over-exploitation
with reference to an example, state how natural hazards can affect biodiversity
- Natural hazards can destroy habitats and caused forced migration of species reducing biodiversity in one area .One example is floods, such as the Yangtze river floods in China (2007), that left 14 million people homeless
what is meant by habitat fragmentation?
The process whereby a large area is divided up into different sections. This is because of separation by roads, towns, etc. This causes the edge effect, causing conditions to change
what is the edge effect in habitat fragmentation
when systems are divided into sections, the edge of these sections have less ideal conditions then the conditions in the core of each divided section
what is the IUCN Red List?
A list that collates information regarding the global conservation status of animal, fungi and plant species
name 5 factors that the IUCN use to judge the conservation of a species with
- habitat risk
- population size
- reproductive potential
- amount of food sources
- whether an introduction of an alien species has occurred (i.e. a competitor)
name 3 factors that influence a species status on the IUCN Red List
- whether the species is endemic or not
- its desirability to humans, i.e food, fashion
- the quality of its habitat (is it affected by pollution)
name 2 explained examples of two species on the IUCN Red List (one mammal and one plant)
Caquetá Titi Monkey:
- assessed for the first time since 2012 to be critically endangered
- endemic to easter Colombia - an area of intense human colonisation
- there is widespread habitat destruction and fragmentation
The Rafflesia Plant:
- Tropical parasitic plant found in the jungles of South Asia
- vulnerable -> needs specific conditions to survive and carry out their life cycle
- vulnerable to deforestation and logging
- it is therefore destroyed by humans and has a decreased chance of breeding
give three ways in which efforts are made to protect endangered species
- breeding programs
- policies made against poaching
- laws against deforestation
give two possible effects that extinctions of species may have on human quality of life
-> Reducing Pollination – we rely on pollinators for most of our crops. Losing pollinators could lead to less production and ultimately the extinction of plants.
-> Loss of Medicine – many medications come from plants or animals.
name a species that has become extinct due to human activity and describe one reason why it became extinct
The dodo bird 🦤
-> deforestation, hunting, and destruction of their nests by animals brought to the island by the Dutch
name and explain 2 direct vales of biodiversity
- Food sources: animals are over-exploited to provide food for humans (i.e. swordfish, passenger pigeon)
- natural products: fur seals were nearly hunted to extinction in the 1900s for fur coats
name and explain 2 indirect vales of biodiversity
- environmental services: waste is broken down and recycled by decomposers
- human health: the first antibiotics were obtained from fungi (penicillin)
what is conservation
Making an effort to sustainable use and manage natural resources
what is preservation
protecting what is in a system by not touching it
name 2 issues with conservation and preservation
- often tensions exist between ‘good for the economy and human needs’ and good for the environment
- conservation and preservation are reliant on citizens and governments to do something
name three influences that humans can have to help protect biodiversity
- less plastic packaging
- acting to help local nature reserves
- reducing fossil fuels
what is sustainable development
meeting the needs of the present without negatively impacting the needs of future generations and biodiversity
what are the 2 categories of organisations
- Non-governmental organisations (NGO)
- Intergovernmental organisations (IGO)
what is an example of an IGO?
UNEP
Name 3 characteristics of UNEP as an IGO
- Use of media -> often use media liaison officers to release informative videos and statements
- Response is usually slow as it is difficult to reach a consensus, but they have great political influence with direct access to governments
- Able to pass national laws through international agreements. However, countries do not have to be involved
what are 2 examples of an NGO
- WWF
- Greenpeace
name 2 characteristics of WWF as an NGO
- rely on public pressure rather than legal power
- Participate in leaflets and events (such as Earth Hour where the WWF asked households and business to turn off their electricity for one hour)
name 2 characteristics of Greenpeace as an NGO
- Use media stunts to get their message across to the masses (On July 2019, activists interrupted chancellor Philip Hammond as he gave a speech to the UK’s top city bosses, by drowning out his speech with climate emergency alarms of live TV)
- activities conducted may be illegal
what 3 characteristics of NGOs
- can respond to crises immediately, as organisations are independent and can make their own decisions
- generally unaffected by politics
- advertise on popular channels using footage of own protest activities
what 3 characteristics of IGOs
- has real power to enforce its policy or approach through international agreements and laws
- slow to act - must meet an international consensus and legal requirements amongst all partaking countries
- many nations cannot give opinions on a matter without consulting lawyers and other countries because they represent many nations
what are the 2 types of conservation?
- species-based conservation
- area/habitat-based conservation
Name the 2 government-led strategies to reduce climate change + brief description
-> The Kyoto Protocol (1997, COP): Countries were allocated amounts of C02, and they were allowed to emit
-> The “three amigos” summit (2016): the leaders of USA, Mexico and Canada met and agreed on a set of initiatives to achieve 50% clean energy by 2050
what is species-based conservation?
the conservation of a single species
what factors can cause species to be singled out for species-based conservation?
- threatened
- ecologically important (key-stone species: bees, beavers)
- useful for humans (medicinal plants: willow)
- species with non-use value (aethetics)
what is the CITES?
Conservation of International Trade in Endangered Species of Wild Flora and Fauna
-> looks at illegal wildlife trade
name 4 examples of animals that the CITES looks into that have been illegally traded + brief explanation as to why they were traded
- elephant ivory -> used for the keys of a piano, however, it is not illegal to kill elephants for their ivory. If the object, made from elephant ivory, was made before it was illegal, it is allowed
- parrots -> for pets
- tiger -> for fur
- pangolins -> for food
how many appendixes does the CITES look at and what do they cover?
3 appendixes:
-> 1st appendix: a species cannot be traded internationally
-> 2nd appendix: species can be traded internationally but within strict regulations ensuring sustainability (however, sometimes some species are mistaken for endangered ones and are traded internationally)
-> 3rd appendix: a species is protected in one country that asks for assistance for a law to protect them (i.e. walrus in Canada)
name 2 adv of the CITES
-> it has dramatically reduced the trade in endangered wild species
-> it is an international agreement set up between governments to protect many species becoming extinct
name 2 d.adv of the CITES
-> Governments sign up voluntarily and can opt out at any time
-> Penalties don’t always match the gravity of the crime
name an endangered species
the leatherback sea turtle
name 2 facts about the leatherback sea turtle
-> It is a circumglobal species that can range throughout almost all the world’s oceans. This is because their leatherback can help regulate their temperature
-> In a nesting beach in Mexico (1986) -> 6,500 nests were recorded, but in 1993 only 50 nests were left
name 2 causes for the leatherback sea turtle’s endangerment + explain
- Sea turtles and their eggs are used as food, medicine, tourist products and in numerous cultural practices globally. One example is the growing popularity of turtle soup as a delicacy in Europe
- 55,000 sea turtles die from shrimp trawling every year. This is when large nets are dragged across the sea floor, to scoop up shrimp, but end up catching thousands of turtles as by-catch. This means many turtles die as they are snagged and drown in the nets
name and explain 3 conservation methods for the leatherback sea turtle
-> Reducing mortality in fish nets: (1989) - The US require the use of Turtle Excluder Devices (TED) that have small grates to allow shrimp through but not turtles, restricting them as by-catch. However, some people wire them close, therefore there is no proper way to enforce this by law
-> Headstarting projects: The act of collecting wild turtle eggs, and rearing them in captivity for almost one year. Once they are at a size where their risk of predation decreases, they are released onto their natal beaches
-> Education: Japan is the largest importer and exporter of turtle products, as they refuse to agree to international trade bans. Therefore, Japanese children are told an ancient Japanese folklore about a boy who saves a turtle and is rewarded for his compassion, as an effort to alter attitudes on sea turtles
