diversity etc etc etc Flashcards
(18 cards)
importance of courtship
to ensure successful reproduction
how can farming techniques reduce biodiversity
-destruction of hedgerows
-selective breeding
-monocultures
-over-grazing
-filling in ponds and draining wetlands
hierarchal system
D Don’t Domain
K Kill. Kingdom
P People Phylum
C Colby. Class
O Or Order
F Friend. Family
G Golbach. Genus
S Sam Species
how does biodiversity help humans
-Provides variety of foods, medicines, shelter&protection, materials, spiritual and cultural value
What conflicts can land use cause?
means people are unsure of how to use land and must review the impacts that building may bring
Explain how grazing and managed burning can be used to prevent succession and conserve ecosystems
When horses eat grass it allows flowers to come through- inc biodiversity of ecosystem- more insects
Better quality plants- more nutrients for animals- hep thriving environment
Burning heather- firebreaks- prevents cause of fire- succession starts again+new plants grow
Succession
Primary succession begins with bare rock that was previously uncolonised. Secondary succession begins with are soil that was previously colonised.
-The pioneer species are able to colonise an environment with hostile abiotic conditions.
-These take root and change the abiotic conditions of the soil making it less hostile and more suitable for ‘new’ species to colonise the environment.
-‘New’ species outcompete the ‘earlier’ species eg for sunlight and the earlier species die off adding humus to the soil.
-This further changes the abiotic conditions making them less hostile and more suitable for new species
-These outcompete the previous species and the cycle continues until climax community reached.
genetic diversity
the total number of different alleles of genes in a species or population.
key for natural selection qs
mutation
reproduction
selection
alleles
selection pressures
things within organisms environments which give some phenotypes a selective advantage and others selective disadvantage.
index of diversity
the relationship between the species richness and number of individuals present in a community
4 reasons why courtship behaviour is necessary
-to recognise members of their own species
-to identify a mate that is capable of breeding
-to form a pair bond that will lead to successful mating and raising offspring
-to synchronise mating ensuring the maximum probability that a sperm and an egg will meet
courtship behaviours
-visual displays e.g. puffing up chest
-vocal displays
-scent spreading
-nest building
suggest how selective breeding might affect genetic diversity of a polyulation
select certain particular individuals only those specific alleles are being passed on reducing genetic diversity.
genetic bottlenecks
events that cause a big reduction in a population. this reduces alleles in gene pool and so reduces genetic diversity.
founders effect
describes what happens when just a few organisms from a population start a new colony and there are only a small number of different alleles in initial gene pool.
directional selection n
where individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce and pass on these alleles to future generations
stabilising selection
where individuals with alleles for cgaracterutus towards middle range are more likely to survive reproduce and pass alleles to offspring for future gens
