C2 - Biodiversity

biodiversity

the number of species and the number of individuals in each species in a specified region

How does light intensity cause spatial variation? (4)

more plants can grow in high light intensity than low light intensity, so supports herbivores, in turn carnivores, greater biodiversity in a bright environment than a dull environment

How does energy cause spatial variation? (3)

more energy in an ecosystem produces more species and more individuals, a high light intensity produces a high energy input, equatorial regions have higher biodiversity than polar regions

biodiversity hotspots

positions of major areas of biodiversity

succession (3)

change in the composition of a community over time, caused by the community of organisms changing it, increasing animal biodiversity which ultimately decreases plant biodiversity

How does human influence affect biodiversity? (2)

human influence makes environments less hospitable to living organisms, which can lead to extinction

How has biodiversity been reduced in the tropical rainforests of Brazil and Costa Rica? (2)

farming, roads and industry destroy habitats, reducing the number of individuals and driving them to extinction many species found nowhere else in the world

How has biodiversity been reduced in the oceans? (4)

over-fishing has depleted fish stocks and very productive, diverse areas like coral reefs and estuaries are severely stressed, trawlers dredging the ocean floor disrupts habitats, damages populations of invertebrates, fish and sea mammals

How has biodiversity been reduced by misuse of land? (4)

trampling by cattle, alongside temperature increase due to climate change, increases the surface area of deserts, e.g. expanding Sahara Desert

How has biodiversity been reduced by water pollution? (2)

industrial chemicals, e.g. baji dolphin was declared extinct in 2006 also with capture and collisions with river traffic in Yangtze River

What instance did human influence increase biodiversity? (2)

building sewers in the River Thames, allowing the river to accommodate salmon, sea horses, heron, kingfishers, dolphins, porpoises and a seal

Which staple foods do plant species provide humans? (2)

wheat, rice

Which medicinal drugs are provided by plants and fungi? (3)

aspirin, statins, antibiotics

Which raw materials do living organisms provide? (2)

cotton, rubber

What is the selfish human-centred argument for the significance of reduced biodiversity? (3)

humans become more endangered as biodiversity decreases, losing potential new food and sources of new and useful characteristics to breed into crops, compromises potential for discovering new medicinal drugs and raw materials

What is the non-selfish argument for the significance of reduced biodiversity? (2)

organisms are unique, we have to preserve their uniqueness due to their intrinsic value

biodiversity index (2)

monitor biodiversity of a habitat over time, for comparing biodiversity in different habitats

What does Simpson’s biodiversity index describe?

biodiversity of motile organisms

What does a higher value outcome of Simpson’s biodiversity index correspond with?

higher biodiversity

Calculation of Simpson’s Diversity Index

Diversity = 1 - sum of number in each species(number in each species - 1)/total number of organisms present(total number of organisms present -1)

How can you assess biodiversity using polymorphic loci? (2)

examining genes and alleles, focuses on alleles present in the gene pool of the population

polymorphism (2)

the occurrence of more than one phenotype in a population, with the rarer phenotypes at frequencies greater than can be accounted for by mutation alone

locus

a gene’s position on a chromosome

polymorphic

when a loci has two or more alleles

Finish the sentence: For a particular gene, the greater the variation of alleles present in a population…

the greater the biodiversity in relation to the characteristic associated with that gene

DNA fingerprinting

organisms that are more closely related to each other have DNA base sequences that are more similar

What causes individuals to acquire different base sequences?

non-coding sequences of DNA undergo mutation

SNPs

single base sequences

What does SNP stand for?

single nucleotide polymorphisms

HVRs and STRs

regions of DNA that vary about 20-40 base sequences long

What does HVR and STR stand for?

hyper-variable regions, short tandem repeats

genetic or DNA fingerprint or profile (3)

terms for a pattern unique for each individual, related to the base sequences of their DNA, including the number of times the lengths of non-coding DNA are repeated

How can you find out how similar or different a population’s DNA sequences are?

by comparing the number and position of the bands in the DNA profiles of the population

What would a biodiverse population show on a genetic or DNA fingerprint or profile?

DNA fingerprints showing a lot of variation

natural selection (3)

gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of individuals possessing those characteristics, introduced by mutations

Outline the order of natural selection (6)

mutation, variation, competitive advantage, survival of the fittest, reproduction, pass advantageous alleles to offspring

Stage 1 of natural selection (2)

mutation, differences in DNA

Stage 2 of natural selection (2)

variation, different physical appearance, biochemical function or behaviour

Stage 3 of natural selection (2)

competitive advantage, some are more suited to the environment than others and outcompete rivals for resources

Stage 4 of natural selection (2)

survival of the fittest, those more suited to the environment survive better

Stage 5 of natural selection (2)

reproduction, those more suited to the environment have more offspring

Stage 6 of natural selection (3)

pass advantageous alleles to offspring, offspring inherit advantageous alleles, so they are also more suited to the environment

What happens in a habitat that undergoes change such as getting warmer and then gets wetter? (2)

over many generations individuals with alleles more suited to warmer climate will produce more efficiently until the majority of the population has those features, if it gets wetter other alleles will increase

In what situations would natural selection decrease biodiversity? (6)

when a selective insecticide kills all aphids in a habitat, when an asteroid crashes into the earth it throws dust into the atmosphere, reducing light intensity, so the plants cannot survive, causing herbivores to die so carnivores die, may cause extinction of species e.g. dinosaurs

adaptation

the change in a species as a useful characteristic becomes more common

adaptive trait

useful characteristic

How are sharks, dolphins and penguins adapted? (2)

streamlined bodies, without this they would be less efficient at catching food or escaping predators

How are beelines an adaptation of some plants? (3)

they indicate the centre of the flower, the source of nectar and pollen for visiting insects, a flower without beelines would attract fewer pollinators

What physiological traits do mammals and birds have, using hedgehogs as an example? (4)

they are endothermic, so must not waste energy and maintain body temperature in the cold, hedgehogs hibernating decrease body temperature from 34 degrees celsius to 30 degrees celsius, so it requires less energy

What physiological traits do deciduous plants have? (5)

when temperature and light intensity decrease in autumn, leaves fall off, in order to not lose water by evaporation, to prevent dehydration through winter when water may be frozen, so they can survive cold weather

What behavioural traits do many plants have? (2)

plants flower in spring when its pollinating insects have emerged, if it flowered earlier it would not be pollinated

How are mating rituals behavioural traits? (3)

increase animal’s chance of reproducing, such as the display of peacock’s tail, elaborate dances performed by birds such as flamingos