chapter 3.1 : biodiversity and e olution

biodiversity

the variety of life on Earth, including species, genetic and habitat diversity

what does biodiversity consist of?

species richness, species evenness and habitat, species and genetic diversity

species richness

the number of species of different animals, plants, fungi and microorganisms in ecosystems

species evenness

the relative proportion of individuals of each species

resilience

the capacity of an ecosystem to withstand disturbance and still maintain the same functions of organisms working together to maintain a balanced sustainable ecosystem

species diversity

is the product of species richness and species evenness

diversity index (D)

gives a quantities estimate of biological variability in space or time and describes and compares communities

when should a diversity index be used

when comparing 2 similar communities

what can low biodiversity index in a similar community suggest?

pollution or recent colonisation

why isn’t species number alone a full measure of biodiversity

because it doesn’t show species evenness or change over time

why should biodiversity be measured over time?

to see if changes are natural or human caused

how can human activites affect biodiversity

they can increase or decrease it, helping evaluate conservation success

what affects the value of simpsons index (D)

higher species richness and evenness increase D. 1 is the lowest possible value

genetic diversity

the range of genetic material present in a gene pool or population of a species

how does individuals affect the genetic diversity

each individual in a species has a slightly different set of genes from any other individual in that species

what does having more individuals benefit genetic diversity

more individuals means higher genetic diversity , leading to a bigger gene pool

how does populations affect genetic diversity

if a species is made up of two or more different populations in different places, then each population will have a different total genetic make-up

why does a high population impact genetic diversity

conserving different populations of a species help ma impose genetic diversity

explain a cheetah’s genetic diversity

they have a low diversity because 10,000 years ago and recent threats of habitat loss and poaching reduced their numbers. Low diversity makes them vulnerable to extinction

habitat diversity

the range of different habitats per unit area in a particular ecosystem or biome

what does the complexity of an ecosystem impact?

the ,ore complex the food web, the more resilient is it to the loss of one species or reduction in its population size

how does the stages of succession impact biodiversity?

in the early stages, abiotic conditions are harsh and the temperature, water supply and nutrients are low; biodiversity is low because more vulnerable to disturbances and less resilient

how does limiting factors and stability impact biodiversity?

not having enough raw materials - water supply and nutrients - can limit the amount of growth leading to low resistance

how does the age of the ecosystem impact the biodiversity?

the older the ecosystem, the greater the biodiversity is likely to be

what is an example of a biome with high habitat diversity

a tropical rainforest

high biodiversity’s advantages (tropical rainforest)

high resilience and stability due to range of plants present, genetic diversity, resilience to disease

disadvantage of high biodiversity (tropical rainforest)

high diversity could lead to the break down of a habitat or degradation when species richness is due to pioneer species invading bar areas quickly