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
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 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
label this eukaryotic plant cell
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
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
vascular bundle
pic
how closely related are the three domains
how do you write binomial nomenclature
