topic 4: biodiversity and natural resources Flashcards
species
group of organisms with similar morphology, physiology and behaviour. that can interbreed to produce fertile offspring. re productively isolated
habitat
a place with particular set of conditions that supports a distinctive combination of organisms
population
a group of interbreeding individuals of same species found in an area
community
made up by various populations in a habitat
Niche
is the distinct role of a species in an ecosystem
endemic
the specific area where a species is found.
behavioural adaptations
any actions by an organism that helps them survive and reproduce.
physiological adaptations
features of internal workings of organisms that help it survive and reproduce
anatomical adaptations
view-able structures of an organisms that helps it survive and reproduce.
co-adaptation
where two species dependent on each other becoming more closely adapted
evolution by natural selection
- introduction of selection pressure caused by change in environment, competition or predators.
- random mutations produce new alleles which is advantageous. this is caused by natural genetic variation
- individuals with the advantageous allele survive and reproduce.
- advantageous allele is passed on.
- there is a increased frequency of the advantageous allele in the population / gene pool.
gene pool
consist of all the alleles of all genes present in a population
Hardy weinberg equation
used to calculate allele frequencies
p2 + 2pq + q2 = 1
p2 frequency of homozygous dominant 2pq frequency of heterozygous q2 frequency of homozygous recessive q= frequency of dominant alleles p= frequency of recessive alleles
the ability of a population to adapt to new conditions depends on:
- strength of selection pressure
- size of gene pool (population)
- reproductive rate
can a species be perfectly adapted?
- adaption perfection makes a species too interdependent and vulnerable
why aren’t species perfectly adapted?
- there is a time lag before population starts to adapt to selection pressure by natural selection.
- even in a stable environment, mutations occur constantly some being harmful leading to an ill adapted population.
why is it beneficial to become adapted to a specific niche
this helps you avoid competition.
as if you had the same niche as another species you would compete
speciation
the formation of a new species
reproductive isolation
when a group is re productively isolated from the rest of the population
an accumulation of different alleles frequency occur
eventually the group is so genetically different they are unable to successfully breed with the rest of the population and so become 2 different species.😁
biodiversity
the wealth of different species that exist as a result of natural selection
biological diversity
variety of species that belong to every different group of organism
binomial system
each species has a unique 2 part latin name.
part 1: genus which is shared by closely related species
part 2: unique to the species
taxonomy
placing organisms into groups based on shared features
taxonomic hierarchy
series of taxa which members all share one or more common feature
- kingdom
- phylum
- class
- order
- family
- genus
- species
types of kingdoms
animali plantae fungi protoctista prokyaryotae chromista
kingdom animali
muticellular eukoryates that are heterotrophs
kingdom plantae
muticellular eukoryates that are autotrophs
kingdom fungi
muticellular eukoryates that are heterotrophs or absorb nutrients from decaying matter
kingdom protoctista
eukaryotes that photosynthesis or feed on organic matter
but not included in other kingdoms
kingdom prokaryotae
prokaryotic organisms
kingdom chromista
includes some groups of fungi plantae and protoctista. which all have tinsel like flagella. the shared features between them make them more closely related to each other than any other kingdom
the 3 domains
archaea
bacteria
eukaryota
carl woese
aimed to define the evolutionary relationship of prokaryotes
using RNA sequencing found group of bacteria caled methanogens that lacked sequence characteristics of bacteria and proposed a new domain archaea
phylogenetic trees
represent evolutionary relationship based on the best existing evidence
convergent evolution
unrelated organisms evolving similar appearances as they adapt to the same conditions.
e.g dolphins and sharks
the opposite of convergent evolution
is very common
where closely related organisms look completely different from their close relatives.
different phenotypic traits from close relatives.
e.g dogs
evaluate classification of species
it is difficult to classify without use of DNA analysis
classification enables use to look at evolutionary relationship
- useful when trying to find sources of chemicals with medicinal and other beneficial properties
what are the sources of genetic variation (6)
- gene (point) mutations
- chromosomes mutations
- idenpendent assortment
- crossing over
- mate selection
- random fertilisation
explain meosis involvement in genetic variation
independent assortment : each homologous pair is sorted independently. so it is at random which side the end up on.
crossing over: pieces of genetic material are exchanged between homologous chromosomes.
explain the role of mutation in genetic variation
gene point mutations: alternations in DNA base sequence arise usually in replication but can also arise in other parts of the cell cycle
explain the mating role in genetic variation
mate selection
random fertilisation: different combinations of alleles come together depending on the egg and sperm which is random.
species richness
a way to measure biodiversity. counting the number of species present in a habitat
species evenness
community with species of similar abundances are said to have high species evenness.
measure of the number individuals in each species
what makes a community highly diverse
high species richness and high species evenness
diversity index
calculates a score for biodiversity based on evenness and richness which can be used to compare habitats.
D = N(N-1) / total n(n-1)
N= total no. of organisms of all species
n= total no. of organisms of each species
biodiversity hot spot
an area of particularly high biodiversity.
the worlds biodiversity is not evenly distributed
25 regions covering 2% of earth’s land contains more than 50% of all species
how can you measure genetic diversity
DNA sequencing determines the alleles present.
genes from a group is sampled and alleles recorded.
database is used to calculate index that quantifies genetic diversity
conservationist use genetic diversity of population to decide which one to conserve
what are plant cell walls made of
cellulose. which is a polymer of alpha and beta glucose.
each chain contains 1000 - 10000 units. straight chain. H bonds form between OH groups of neighbouring chains forming bundles called microfibrils which are about 60 -70 cellulose molecules wound in helical arrangement stuck together with polysacharide glue
what is polysaccharide glue
composed of short branched polysaccharides known as hemicellulose and pectins. bind the surface of cellulose and to each other to hold microfibrils together.
what are pectins
are an important component in the middle lamella the region between adjacent cells as it acts as a glue to hold cells together.
what makes the cell wall so strong
the arrangement of cellulose microfibrils with matrix of hemicellulose and pectins make it very strong
what are xylem vessels
tubes for transport of water and aqueous minerals. they also have stiffened cell walls which support the plant.
how to xylem vessels form
- ligin impregnates cellulose wall. the wall becomes lignified and waterproof.
- tonoplast of cell breaks down and autolysis of cell contents leaving dead empty tube of cell.
- walls between cells are lost or highly perforated resulting in long continuous chain
- cellulose microfibrils and lignin in cell wall makes tubes very strong support
steps in transpiration stream
- water vapour diffuses out through stroma down diffusion gradient
- water evaporation from surfaces of cell lining substomatal cavity.
- water replaced by means of capillary action within cell walls.
- water is drawn out of xylem
- a continuous column of water is drawn up through xylem
explain cohesion-tension theory
adhesion: H bonds between water molecules and cell wall
cohesion: H bonds between eater molecules
surface tension: caused by cohesion
what does the movement of water through xylem also provide
a mass flow system for the transport of inorganic compounds
what are phloem sieve tube cells
a series of cells that form a long tube for the transport of organic solutes.
does not provide any support.
how are phloem sieve tubes formed
sieve tube cells remain alive
nucleus and most cell content disintegrate during development leaving most of the cell as liquid filled space (lumen)
- the end walls become perforated these are called the sieve plates and allow the transfer of materials through each cell.
- the companion cell purpose is to perform metabolic functions for the sieve tube cell
what are transfer cells
a type of parenchyma cell that transports solutes into the sieve tube. cell walls and surface membrane have many in folding to increase surface area. numerous plasmodesmata linking cells. lots of mitochondria provide energy for loading
what are the steps in mass transport
- photosynthetic products are actively loaded into phloem increasing solute concentration. which draws water into sieve tubes by osmosis from adjacent xylem vessels
- this increases hydrostatic pressure at loading end
- at sink, solutes are unloaded lowering hydrostatic pressure. the difference in pressure between loading and unloading site causes mass flow along the sieve tube from high to low pressure
what is the sink
the sink is where photosynthesis does not occur and so needed the products delivered to them. they have the role of turning sugars into starch.
sclerenchyma fibres
coloms of cells with stiffened walls which provide support
are associated with vascular bundles and are also lignifeied and die once lignified leaving a hollow fibres the strength of which depend on length and degree of lignification
why are plant fibres so usefull
- long and thin
- flexible
- strong
how do bacteria reproduce
bacteria reproduce asexually and in a processes called binary fusion
where circular DNA replicates and new cells contents are synthesised before a new cell wall forms dividing cell in half.
what are the ideal conditions for bacteria
- sufficient nutrients
- optimum temp and pH
- no build up of toxic waste
- sufficient oxygen
the stages in bacterial growth in a closed system
- lag phase
- exponential growth
- stationary phase
- death phase
what happens in lag phase
cells are adjusting to the conditions
what happens in exponential phase
also known as logarithmic growth.
cells dividing exponentially at fastest rate possible for conditions
what happens in stationary phase
growth is limited by a factor in environment e.g build up of toxic waste.
there is a balance between cell division and cell death..
what happens in the death phase
also known as logarithmic decline
the number of cell deaths is greater than cells formed
explain withering’s research into foxgloves
withering digitalus / foxgloves and dropsy
digitalin in foxgloves can treat dropsy (oedema)
studied 163 patients recorded side effects: nausea, vomiting, diarrhoea, yellow vision and large production of urine.
getting the does right was crucial. with each patient he slowly increased dose until they showed symptoms and then reduced it very slightly to get perfect dose
what are the stages in modern drug testing
- pre-clinical testing
- clinical trials phase 1
- clinical trials phase 2
- clinical trials phase 3
- after licensing
what happens in pre-clinical testing
animals and isolated cell and tissue cultures asses safety and determine the compounds effect
what happens in clinical trials phase 1
small group of healthy volunteers are given different doses to confirm whether compound is being absorbed, distributed, metabolised and excreted as predicted.
as well as looking at the effect of doses and side effects.
what happens in clinical trials phase 2
small group 100-300 of patients with disease treated with drug to look at drugs effectiveness
what happens in clinical trials phase 3
large group 1000 - 3000. with placebo. double blind randomised control trial. look for statistical improvement and adverse reactions
what happens after licensing
trials continue on effectiveness and safety
seeds are adapted to ensure
- protection for embryo
- dispersal
- provide nutrients for the new plant
how are plant seeds formed
- flowing plant produces ovule fertilised by nucleus from pollen grain.
- outer layer of ovule becomes lignified forming tough seed coat.
- surrounding ovary develops into fruit add seed dispersal.
- monocotyledons stored food in seed outside embryo in endosperm.
- in dicotyledons embryo absorbs nutrients from endosperm and food in seed leaves swell.
- distributed by wind, animal, water or self.
- when conditions are suitable dormancy broken and seed takes water in triggering metabolic changes.
what is the primary threat to species and habitats
human activity in the forms of: land development causing destruction, fragmentation and degradation. over-exploitation introduction of alien species pollution.
in situ conservation
conservation management applied on site to protect and maintain fragile habitats
ex situ conservation
vulnerable populations in the wild supported through zoos and seed banks. offsite
what is the role of zoos
- tourist attraction
- play significant role in conservation, research and education.
what are captive breeding programs
zoos try to successfully breed animals
what are the aims of captive breeding programs (3)
a. increases number of individuals of a species
b. maintaining genetic diversity in captive population
c. reintroduction of animals if possible
define genetic drift
small population, some alleles are not based down by chance.
resulting in change of allele frequencies leading to reduction of genetic variation
define inbreeding depression
small population
closely related individuals mating increases frequency of recessive homozygousity.
many recessive alleles have harmful effects leading to animals being less adapted.
what are stud books
studbooks records history and location of all captive individuals of a species.
provides the raw data from which breeding programs are drawn.
ensuring genes from founders are retained and equally represented in future generations.
poor breeders must be encouraged to breed
successful breeders must be limited
define cytogenetics
is the study of the structures of chromosomes and molecular biology
used to complete stud book data.
what is the millennium seed bank MSB
plants are threatened by habitat destruction, climate change and over harvesting.
in situ conservation remains at risk of disasters.
the MSB conserves 13% of the worlds plant species
how are seeds stored
- seeds are collected from site.
- seeds are cleaned and dried for every 1% moisture reduction the life span doubles
- seeds are placed in cold storage -20oc . every 5oc decrease in temp doubles lifespan.
- after a month a sample is taken to ensure germination.
- every 10 years a sample is taken if germination falls bellow 75% the seeds are grown out and new ones collected from them.
what are seed samples used for
- research
- habitat restoration
- species reintroduction
