Topic 4: Biodiversity and Natural Resources Part 1 Flashcards
define biodiversity
the number of different species and the genetic variety within a given species
define species
organisms of the same type are said to belong to the same species. it is a group of organisms that can reproduce with one another to produce fertile offspring
define community
all the different species in a habitat
define habitat
the place where an organism lives
what is species richness
the number of species in a given habitat, the greater the no. of species, the greater the species richness
what is species evenness
determines the abundance of each species in a community, a high species evenness would mean there are similar abundances of species
What is simpson’s index of biodiversity
N vs n
describes relationship between no. species present and how each species contributes to the total no. of organisms present in that community
n = total no. of one species
N = total organisms in community
when using n you have to do it for each different species then add together, that’s why sigma is used
why is biodiversity measured?
to compare different areas at the same time
to compare the same area at different times
what is species diversity
a measure of how many different species are present in an area and how many individuals of these species (the population) that there are in the community being studied
what is habitat diversity
a measure of how many different habitats are present in an area including biotic and abiotic factors
what is genetic diversity
the variety of alleles in the gene pool (complete allele set in a species of population) of a species
what factors are considered in measuring genetic diversity
phenotype - look at the observable features
genotype - measure the number of alleles a species has for one characteristic, take DNA and analyse the order of bases, look at the heterozygosity index
what is endemism
when a species evolves in isolation and is found in only one place worldwide
how do you calculate the heterozygosity index
H = no. of heterozygotes/no. of individuals in population
it’s used to measure the genetic diversity of a species
what does a heterozygosity index measure
a measure of genetic diversity within a species/population
what is the hardy-weinberg principle
it states that if:
• Mating is random between individuals
• The population is infinitely large
• There is no migration, mutation or natural selection
allele frequencies of a gene within a population will not change from one generation to the next
what are some adaptations of a polar bear vs a camel
polar bear - thick white fur, thick blubber layer, large feet, small SA/V ratio, black skin
a camel - long eyelashes, large feet, nostrils close, fat store in hump so there’s little around limbs, long legs, pedestal
what is a niche
the way an organism exploits (uses) it’s environment, it’s interactions with living organisms ( ie what it eats or gets eaten by), interactions with non-living environment, it’s shelter site
competition can occur between individuals with a similar niche
outline the kinds of adaptations can an organism have
anatomical - adaptations of structures that can be seen or observed when dissecting an organism eg. bumble bees have baskets for collecting and transporting pollen
behavioural - actions carried out by the organism to help them survive or reproduce eg. plants turning their leaves to the sun
physiological - internal workings within the organism that help them to survive or reproduce eg. fish, birds and whales can drink salt water but humans can’t
there can be overlap between these categories
describe the chi-squared test
‘goodness of fit test’
it is used to see how closely experimental results fit expected results; it can useful in Genetics to see if observed ratios match expected ratios
- set up a null hypothesis
- calculate the chi-squared value (add columns to your table for each step) DECIMALS OKAY!!!!
- NO. OF CATEGORIES - 1 = DEGREES OF FREEDOM
- use this and a p value of 0.05 to find the critical value
critical value < calculated = significant
chi squared equation is given;
O = observed value
E = expected value
outline how evolution occurs
- a population has some naturally occurring genetic variation with new alleles created through mutations
- a change in environment causes a change in the selection pressures acting on the population
- an allele that was previously of no certain advantage now becomes an advantageous allele
- organisms with the allele become more likely to survive, reproduce and so produce offspring
- their offspring are more likely to have the allele
- they reproduce and so it becomes more prevalent in the population
what is genetic drift
a random change in allele frequency
it affects smaller populations more than big ones
what affects a population’s ability to adapt to new conditions
- selection pressure
- size of the gene pool
- the reproductive rate of the organism
define speciation
the evolution of 2 or more species from an existing species
explain speciation
- occurs when populations of a species are split by an isolation mechanism
- there are now 2 reproductively isolated populations of one species
- so there is no genetic change between them
- sufficient selection pressures acting to change the gene pools and allele frequencies within both populations will allow the 2 populations to eventually diverge and form different species
- a change in alleles and gene pools influences phenotype which will cause them to differ physiologically, behaviourally and anatomically over time
what is allopatric speciation
the evolution of new species as a result of geographical isolation, features like mountains, rivers and lakes can separate populations and the feature acts as a barrier to gene flow in the population
what is sympatric speciation
evolution that occurs while the populations inhabit the same geographical location as a result of reproductive isolation because of mutations changing certain characteristics
what are some causes of reproductive isolation
- seasonal changes; individuals from the same population can develop different flowering/mating seasons or may become sexually active at different times of year
- mechanical changes; changes in genitalia prevent successful mating
- behavioural changes; a group of individuals develop courtship rituals that aren’t attractive to the main population
what is taxonomy
the science of classification, organisms are named and put into groups based on similarities and differences, making it easier for scientists to identify and study them
how does the binomial naming system work
the first name is the Genus of the organism; it’s the general one
the second name is the Species of the organism; its the specific name
I allows scientists to agree universally on the names of organisms
the genus depicts more similarity than the species
what is the hierarchical system
kingdom
phylum
class
order
family
genus
species
what is a taxonomic hierarchy
a series of nested groups/taxa in which the members all share 1 or more common features, or homologies
it is based on phenotype
(king prawn curry)
are all similar looking organisms related
organisms can superficially look similar and not be closely related, they only look similar because they’ve adapted to similar conditions
what is the 3 domain system
a newer classification system based on molecular phylogeny; it included archaea, bacteria and eukarya
molecular phylogeny relies on similarities/differences of DNA and amino acid sequences between groups of organisms to determine how closely they’re related
the more similar the molecules, the more closely they are related
it provides more evolutionary evidence by analysing common genome amino acid sequences
what are the 5 kingdoms
prokaryotae
protoctista
fungi
plantae
animalia
outline the prokaryotae kingdom
eg. bacteria
they are prokaryotes and are unicellular with no nucleus
usually <5μm
outline the protoctista kingdom
eg. algae, protozoa
eukaryotic cells that don’t fit in the other kingdoms so there’s variation
usually in water, can be single celled/simple multicellular organisms
outline the fungi kingdom
eg. moulds, yeasts, mushrooms
eukaryotic, chitin cell wall, saptrotrophic (absorb substances from dead/decaying organisms)
outline the plantae kingdom
eg. mosses, ferns, flowering plants
eukaryotic, multicellular, cellulose cell wall, able to photosynthesise, contain chlorophyll, autotrophic (produce their own food)
outline the Animalia kingdom
eg. nematodes, molluscs, insects, fish, reptiles, birds, mammals
eukaryotes, multicellular, no cell walls, heterotrophic (consume plants and animals)
what is in situ conservation vs ex situ conservation
in situ is ideal, it protects ecosystems and maintains fragile habitats
ex situ is when vulnerable populations in the wild are supported through the work of zoos and seedbanks
how can zoos contribute to the conservation of endangered species and their genetic diversity
carry out scientific research - it can be in the zoo or on expeditions to an animals natural habitat to help inform conservation
captive breeding programmes - they aim to increase the no. of individuals in the species if numbers are low, maintain genetic diversity in the captive population and reintroduce animals into the wild if possible
zoos share animals and use IVF to prevent small gene pools (keep studbooks to log info)
reintroduction programmes
education programmes - promote endangered species, raise conservation funds, change human behaviours, share expertise
studbooks log which zoo animals are at and who they are related to to prevent inbreeding and maintain/increase the genetic pool
what do seedbanks do and how do they store
store seeds from various endangered plants to help conserve biodiversity in case of extinction
store a range of seeds from different seeds bc they have different alleles
stored in cold and dry conditions, seeds have to be tested for viability (their ability to grow into a plant), seeds are planted and grown and new seeds are harvested to put back into storage
evaluate seed banks
+ storing seeds is cheaper than fully grown plants
+ more can be stored than plants
+ less labour used than with plants
+ can be stored anywhere cool and dry, plants would need their original habitat
+ seeds are less likely to be damaged by disease, natural disaster or vandalism
– can be expensive and time consuming to test for viability
– it would be too expensive to store all types of seed and test them for viability regularly
– some plants may grow in remote places, making seed collection difficult
what adaptations do seeds have
- ensure protection of the embryo
- aid dispersal
- provide nutrition for the new plant
what happens after seed dormancy is broken
the seed takes in water through a small pore in the seed coat
absorbing water triggers a metabolic change in the seed and enzymes that mobilise stored food reserves are produced
maltase and amylase break starch down to glucose which is converted to sucrose for transport to the radicle (young root) and plumule (young shoot)
proteases break protein down to amino acids
lipases break stored lipids down into glycerol and fatty acids
outline some uses of starch from seeds
thickening - heating starch granules in water makes them suddenly swell, absorb water and thicken the liquid; this is gelatinisation and is used in custard and wallpaper paste
stiffening fabrics - sizing is the stiffening of cloth/paper, its used very often and done by applying a starch mixture to the surface which is gelatinised and cooled, allowing bonds to form between the starch molecules. adding water reverses the stiffening (plasticisation) and this allows the shape to be changed
super-absorbents - chemically cross linking starch before gelatinisation forms particles which can be dried and rehydrated so that they can take up large amounts of water and can be found in nappies
starch foam - the more water in the starch mix, the lower the gelatinisation temperature will be; raising the pressure at the same time makes the starch form a plastic mass and then releasing the pressure suddenly will form steam and make the starch puff into an expanded structure; this technique is used to make foam packaging
describe the cell wall and it’s function in plants
its a rigid structure that surrounds plant cells, it is mainly made of the carbohydrate cellulose
it supports plant cells
describe the middle lamella and it’s function
it is the outermost cell layer
it acts as an adhesive and sticks adjacent plant cells together, giving the plant stability
describe the plasmodesmata and it’s function
they are channels in cell walls that link adjacent cells together
a cytoplasmic connection between cells
they allow communication and transport of substances between cells
describe pits
regions of the cell wall where it is very thin, they’re arranged in pairs meaning that the pit in one cell is lined up with the adjacent cell’s pit
allows substabc transport between cells
describe a chloroplast and their function
it is a small, flattened structure that is surrounded by a double membrane and thylakoid membranes are stacked to form grana, these are linked together by lamellae which are thin, flat pieces of thylakoid membrane
the many layers increase surface area to absorb light
they contain chlorophyll to absorb light
they have electron carrier molecules in the thylakoid molecules for ATP production
it is the site of photosynthesis, some of it occurs in the grana and some occurs in the stroma, which is a thick fluid found in chloroplasts
describe an amyloplast and their function
it is a small organelle enclosed by a membrane, they contain starch granules
stores starch grain and converts starch back into glucose for release when requires by the plant
what is the vacuole and tonoplast and describe the function
the vacuole is a compartment surrounded by a membrane called the tonoplast
vacuole contains: the cell sap (which is made of water), enzymes, minerals and waste products
vacuoles keep the cell turgid, preventing the wilting of plants and are involved in the breakdown and isolation of unwanted chemicals in the cell
the tonoplast controls what enters and leaves the vacuole
outline starch in plants
it is the main energy storage molecule in plants; excess glucose is stored as starch in chloroplasts and amyloplasts
starch is made of2 a-glucose polysaccharides: amylose + amylopectin
amylose - long, unbranched chain, 1-4 glycosidic bonds angle give it a coiled structure, making it compact and good for storage
amylopectin - a long, branched a-glucose chain, 1-4 and 1-6 glycosidic bonds leave a branched molecule
so many terminal glucose molecules that can be easily hydrolysed for respiration and added to for storage
what’s the difference between alpha and beta glucose
ABBA
alpha below, beta above
in reference to the CH2OH side chain
add pic?
outline cellulose
it is a polysaccharide and the main component of plant cell walls
it is made of long, unbranched, ß-glucose chains that are joined by 1-4 glycosidic bonds (each ß-glucose is inverted 180˚to allow these bonds to form; the bonds are straight so the cellulose chains are straight
50-80 cellulose chains are linked together with hydrogen bonds between cellulose chains, to form strong threads known as microfibrils, these allow cellulose to provide structural support for cells
compare and contrast cellulose and starch
- both are glucose
- one is a beta-glucose polysaccharide and the other is alpha-glucose
- starch is an energy storage molecule and cellulose is a structural molecule of plant cell walls
- starch has alpha-1,4 and alpha-1,6 glycosidic bonds, cellulose has ß-1,4 glycosidic bonds
- starch is made of branched and unbranched glucose, cellulose is made of only unbranched glucose
- cellulose is stronger than starch
label this eukaryotic plant cell
outline an experiment on plant mineral deficiencies
- make up 3 nutrient broths, each with a different concentration of calcium ions; high, medium and low
- split 9 test tubes into 3 groups and fill the tubes of each group with one of the broths
- take 9 seedlings of the same plant and measure and record the mass of each. place into the top of a test tube so that the root is suspended in the nutrient broth, support the. seedling using cotton wool in the tube’s opening
- cover the outside of each test tube in aluminium foil so that light can’t get to the broth and cause the growth of other organisms like algae
- place them all near the same light source, a windowsill and leave for the same amount of time, 2 weeks. top up the nutrient broths when necessary to keep the roots suspended
- remove each plant gently and blot dry, measure and record the new mass and calculate the mean change in mass for each nutrient broth; also note down visual differences between groups
what are error bars
they help indicate uncertainty and how precise a measurement is
a short error bar means the values are concentrated and a long one means that they are more spread out and are less reliable
skewed data will make the bars inequal; they won’t be the same length above and below
an overlap in error bars means that the difference is significant
they can represent standard deviation
PCITURE
how are seeds selected for storage in a seed bank
choose seeds from various plants in a species to provide genetic variation
X-ray the seeds to check for viable embryos
how is water transported in a plant
transpiration is the water loss from leaves by evaporation
- water moves up the xylem bc of a hydrostatic pressure difference (lower at top), this lowers hydrostatic pressure in the root, so water constantly diffuses from the root tissues and the soil
- movement of water from soil to plant = transpiration stream
- the column of water being pulled up the xylem is prevented by falling from gravity because of upward pull + adhesion forces between lignin and water
- the pull plus adhesion to wall puts water columns in the xylem under tensions so they’re stretched; cohesion-tension theory of water transport
- water potential of cells in the leaf is lowered by water leaving, so a gradient of water potential is created that draws water from the xylem in the leaf veins (cohesion??)
water can diffuse from cell to cell, via the plasmodesmata or in the cell walls - water vapour diffuses through air spaces in the leaf and out of the stomata, down the diffusion gradient (transpiration)
- leaf absorbs heat energy from sun and water evaporates constantly from leaf cell’s cell walls
what are the ways that water can move through cells
apoplastic route - moves within porous cell walls
- water moves passively and freely through the cellulose walls of cells as a result of the cohesion tension that transpiration creates; cohesive forces between water molecules ensure that water is drawn from across adjacent cell walls
symplastic route - through the plasmodesmata and cytoplasm
- water diffuses along water potential gradient through the cytoplasm of adjacent cells and plasmodesmata
describe xylem vessels
function
transport water and mineral ions up the plant, provide support
structure
- very long, tube-like structures formed from dead cells joined end to end, found together in bundles
- longer than width with a hollow lumen, no cytoplasm and no end walls; forms an uninterrupted tube
- walls are thickened with lignin, which helps to support the plant
- the walls have pits where there’s no lignin water and mineral ions move in and out of the vessels here
pictyre
describe schlerenchyma fibres
function - provide support
made of bundles of dead cells, running vertically up the cell
cells are longer than wide, have a hollow lumen and have end walls
cells are thickened with lignin with No pits, they have more cellulose than other plant cells
pciyre
describe phloem tissue
function - transporting organic solutes from where the plant makes them to where they’re needed; translocation
it is purely a transport tissue (not involved in support)
contains sieve tube elements and companion cells (different cell types)
sieve tube elements - living cells joined end to end to form sieve tubes
they are the end walls, the solute can pass through the many holes
- unlike most living cells; sieve tube elements have no nucleus, a very thin cytoplasm layer and few organelles
- this means they can’t survive alone, so there is a companion cell for every sieve tube element
- the cytoplasm of adjacent cells is connected through sieve plate holes
companion cells - carry out living functions in sieve and themselves, eg. provide energy for solute active transport
vascular bundle
pic
how are organic molecules transported in a plant
translocation moves dissolved substances like sucrose and amino acids from where the substance is made (the source) in the plant to where it is needed (the sink)
it occurs in the phloem and is an active process that requires energy
describe adaptations of leaves that prevent excess water loss
- waxy cuticle is impermeable to water loss
- stomata are on the underside of the leaf where it’s cooler
- thick leaves reduce water loss
- spines/hair increases the boundary layer (undisturbed air layer)
- stomata close at certain times of day
- stomata may be sunken and found in pits`
devise an experiment to measure tensile strength of plant fibres
tensile strength = force/cross-sectional area
measure diameter using callipers
- attach the fibre to a clamp stand and hang a weight on the other end
- keep adding weights in regular intervals until the fibre breaks
- record the mass needed to break the fibre - the higher the mass, the higher the tensile strength
- repeat with different samples of the same fibre to calculate the mean and reduce random error
- calculate tensile strength
controls:
length of fibre
temperature
humidity
safety:
wear goggles for eye protection
don’t stand where toes will get squashed by weights
what is the Hardy Weinberg equation
p + q = 1 (frequency of all alleles)
p^2 + 2pq + q^2 = 1 (frequency of all genotypes)
p = dominant, q = recessive
you generally have to use the genotype equation first
seedbank seed storage conditions
cold and dry
what is a mutation
a change to a DNA base sequence that may result in a change in the amino acid sequence and thus, different alleles forming
what do you do if mutations are mentioned
DEFINE!!!!
how can two organisms be confirmed to be different species
- compare DNA sequences
- compare amino acid sequences
- compare mRNA sequences
- see if they breed to form fertile offspring
how does reproductive isolation occur
- mutations result in new alleles forming
- selection pressures can make the alleles advantageous
- more individuals with advantageous alleles survive and reproduce
- over time the population would no longer be able to reproduce with the other population to form fertile offspring
how closely related are the three domains
how do you write binomial nomenclature
where does the light independent reaction take place
stroma
positions of xylem, phloem and schlerenchyma
xylem: inner side of vascular bundle
phloem: middle of vascular bundle
schlerenchyma: outer side of vascular bundle
how do you assess the diversity in an area
measure biodiversity using a diversity index, higher index means greater biodiversity
assess species richness
assess genetic diversity of the species present
assess whether any endemic/rare species are present
how are mineral ions taken into a plant
by active transport through carrier proteins, requiring ATP
what can a mutation cause
A CHANGE In THE SEQUENCE OF BASES IN DNA —> CHANGE IN AMINO ACID SEQUENCE —> different r groups and diff bonds and folding
what happens if endemic species are lost in an area
that species is extinct! the loss of them will significantly reduce biodiversity
why may two species not interbreed with on another
reproductive isolation due to:
physio anatomical beh. etc
