Topic 4 Flashcards
Explain endeminism and 2 types of biodiversity
-Variety of living organisms in an area
-Species diversity: number of different species in an area
-Genetic diversity: variation of alleles within a species
-Endemism: a species is unique to a single place
Explain natural selection and conservation
-NS: leads to adaptation and evolution, increases biodiversity over time
-Farming + deforestation reduces species diversity, reducing biodiversity
-Conservation: help maintain biodiversity
-Crucial to endemic species as they are more susceptible to extinction
Explain measuring species diversity in a habitat
-Choose an area of habitat to sample
-Avoid bias by doing random sampling, use of a random num generator for a grid to measure
-Count individuals of each species in that area randomly chosen
-Repeat the process, gives more accurte estimate to the whole habitat
Explain niche and 3 adaptations
-Role of a species within a habitat
-Could be its interactions with living organisms (eats or eaten by) or non-living enviroment (O2 breathed in, C02 out)
-Niche can only be occupied by one species
-2 species occupying one niche creates competition
-Adapt to niches behaviourlly, physiologically or anatomically
-B: organism acts dead to avoid being eaten by a predator
-P: Brown bears hiberate to lower metabolic rate in winters
-A: Whales have thick layer of blubber (fat) to keep warm in cold sea
Explain evolution
-Mutations occur, introducing new allles into a population
-A selection pressure arises (predation, disease, competition)
-Individuals without the new advantageous alleles die off
-Individuals with, survive - they go on to reproduce
-Offspring obtain the allele, increasing n.o of individuals with the advantageous allele
-This repeats over generations leading to evolution
Explain speciation
-Species is a group of similar organisms which reproduce giving fertile offspring
-Speciation is development of new species
-Occurs when population of a species becomes reproductively isolated, changes in alleles and phenotypes prevent them breeding
-Reproductive isolation occurs due to geographical isolation or random mutations which introduce new alleles
Advantages of a seedbank
-Cheaper to store seeds than grow
-Large numbers can be stored than grown, due to less space taken
-Less labour to care for seeds
-Cool and dry place is only conditions to store, plants would need habitat conditions
-Seeds are less prone to damage from disease, disaster or vandalism
Disadvantages of a seedbank
-Testing for seed viability can be expensive and time consuming
-Can be difficult to collect seeds from endemic or remotely growing plants.
Explain cell wall
-Made from cellulose
-Rigid structure surrounding plant cells
-Supports the cell
Explain middle lamella
-Outermost layer of a cell
-Acts as an adhesive, sticking adjacent cells together
-Gives plant tissue stability
Explain plasmodesmata
-Channels in cell wall which link adjacent cells
-Allows substance transport and communication between cells
Explain pits
-Regions of cell wall where it is super thin
-Allows substance transport between cells
Explain chloroplast
-Flattened structure
-Double membraned
-Houses thylakoid membranes
-Stacks of T.M are named granum
-Site of photosynthesis
-Happens in grana or in the stroma (a thick fluid)
Explain amyloplast
-Small membraned organelle
-Houses and stores starch granules
-Converted back to glucose for release when required
Explain vacuole & tonoplast
-Vacuole is a compartment surrounded by membrane named tonoplast
-Vacuole contains cell sap, made of water, minerals and waste products
-Vacuole involved in breakdown and isolation of unwanted chemicals
-Tonoplast controls ins and outs of the cell
