a3.1 Flashcards
Variation can be
genetic or environmental
- visual
- behvaioural
- biochemistrty
where does variation occur
- between individuals within a species (no two individuals are ever identical)
- between members of different species, to identify how closely related they are
discontinuous variation
- characteristics that fall into characteristics “black flur” “blood a”
continous variation
mesureable “hights” “weights”
species
- a group of individuals with shared traits
taxomy
organising species based on logical groups
father of taxomy
carl linnaeus
morphological concept
- based on physical traits
- outwards form and inner strucuture
- linneaus based classfication on species on their observae traits eg
- mice across europe who have similar traits but dont have seggs
binomial naming sytem
- system of nomenclature
- universal system of naming
- first word : GENUS
- second word: species
features of naming system
- first word the Genus must be with CAPITAL LETTER
- second word must be lower letter
- use italics
biological species concept
- a different method of grouping species
- this relies on interbreeding and that interbreeding generation after generation maintains characteristics and prevents diverging
biological species concept
a species is a group of organisms that can sucessfully breed and produce fertile offspring
downsides of biological species concept
- fertile hybrids, when two different species produce a fertile off sprint however its usually sterile
- asexual reproduction
- extinct species cannot be tested for reporduction
characteristics used to help determine species
- morphology
- dna comparison
- biochemistry
- ecology (where they live)
- evulutionary lineage
speciation
- when species give rise to two new species
when does speciation occur
- when populations aare isolated
- they cannot breed and flow their genes
- natural selection may act causing species to evolve
- they can then no longer breed
difficulties with speciation
- wether species in different populations are different species
- the ability to reproduce is a gradual priocess
- the rate of changes can be slow to rapid
speciation word
the descion when to sperate a species to two populations is arbitary - random or on a whim
chromosone numbers
- diplod are adult cells with 2N
- haploid are gammates with n and fuse in fertilization to form a gamate
- all cell have the same set of dna in an organism the 2n but each genes are different expressed
human chromosone numbers
- diploid 46
- haploid 23
chimpanzee chromosones
- 48 diploid
- 24 haploid
gene
a section of dna that codes for a polypeptide
metacentric cromosomes
the centromere is in the middle
acrocentric chromosomes
centromere not in the middle
karyotype
apperance of a complete set of an individuals chromosones including number size shape and banding
karyogram
an image that shows all the chromosones of an organism in homologous pairs and decreasing lentgh
what are karyograms useful for
- evolutionary studies
- karyotypes studies
homolgous pairs in a karyotype
they have
- centromere in the same place
- banding in the same place
- same size
making a kayogram
- made during metaphase
- stains used to highlight certain bases
hypothesis of chimpanzee - human development
they say that chromosones 12 and 13 of the chimpanzee fused to form chromosone 2 on humans
evidence for chimpanzee theory
- 12 + 13 make the length of 2 with a slight overlap
- bandings match
- 12 and 2 share a same placed centromere
- in the middle of human 2, there is an area of telometric dna usually found at the ends of DNA, whcih would have been found at the end of chromosone 13 and 13
- there is satelite dna - none coding - wich could be the reminice of the centromere of chromosone 12
genome
all the genetic information of an organism
unitiy and diveristy shown by dna sequencing
- sepcies tend to share all their the same genes wich allows for crossing over and variation
- due to species sharing post dna, SNPs wich is single base changes are used to show differences between species
- snps are the main factor making humans different from one another
heterozygous vs homozygous for an SNP
- homozygous is when both ur parents have the SNP
- heterozygous is when just one parent has it
variation in genomes across different species
- size
- the total size
- this tends ot vary lots between eukaryotes
- genomes very lots in their none coding dna1 - base sequences
- two species bases will be in different postitions
- these differences will accumulate over time
- some genes will remain if they have specific functions
- closley related species tend to have similar genes
measuring genomes
- mass in picograms wich is 10^-12 g
- number os bases in megabseses wich is 10^6 bases
uses of dna sequencing
- evolutionary relations : the more similar they are the more decent the divide of species
- personal medicine : identify vulnerability to diease, prevent side effects of treatment, target specific proteins
cell respiration
releases enegery when molecules such as glucose are oxydised
gas exhange is dependant on
size of diffusion distance
concentration gradients
surface area to volume ratios
gas exhange provides
oxygen for respiration wich is used to break down glucose into ATP
terrrestial gas exchange
in the lunge
auquatic gas echange
gills in fish
features that aid gas exchange
1) permeable: oxygen and carbon dioxide can diffuse freely
2) large surface area in relation to volume of organism
3)moisture: allows for gasses to dissolve
4) thin celled: small surface to diffuse across
gassses and concentration gradients
gasses dissolve down a concentration gradient, eg gasses diffuse into leaves cause they have a lower SA
diffusion can stop concentration gradients
small organisms and concentration gradients
small organisms only respire with oxygen (arerobically) so maintains a concentration gradient
how do large organisms maintain concentration gradients
- dense network of blood vesseles
- a large surface area of diffusing gassses - continous flow
- oxygen is consatnly flowed away and co2 is constantl flowing towards - ventilation
- movement of co2 and oxygen keeps oxygen high and co2 low
lungs are where
in the thorax
trachea
supported by rings of cartilage and to ensure it stays open with the movement of the body
(cilliated epithelium removes particles trapped in mucus)
bronchi
two brinchus strengthened with cartiladge to contract and relax
(cilliated epithelium removes particles trapped in mucus)
bronchioles
lined with smoothe muscle to alter diameters
alveoli
at the ends of bronchioles and surrounded by cappialaries for gas exhange
inhaling (inspiration)
- volume of chest increases
- air pressure inside decreases to lower than the atmosphere outside
- air rushes in the lunge (down the concentration gradient) util it reaches atmospheric
- intercostal external muscles contract and ribcage moves up and out
- diagram contracts and flattens
exhaling (expiration)
- volume of chest decreases
- air pressure inside increases to higher than atmospheric
- air moves out the lungs into atmosphere
- intercostal internal muscles contract and pull ribs down and in
- diagpram is contracted and moves into a dome
lung adaptions
airways:
branching bronchioles
- surface area, thin walls, smooth muscles, not cartilage
alveolar ducts and alveoli
surface area:
there are so many alveoli that the surface area is like 40X larger than the area of the body
capppilary beds
pretty musch surround the entire alvoli
diffusoion distance:
alveoli and cappilaries are thin
moist
cells secrete fluids to keep capillaries moist wich includes pulmonary surfactant to prevent the walls sticking
sperometry
- a chamber filled with air over water
- when filled with air lung capacity can be measures
- when filled with oxygen and soda lime - oxygen consumption can be measures
- HEALTH TESTS
- cystic fibrosisv
- asthma
ventilation rate
air drawn in and expelled per minute
tidal volume
fresh air drawn in and exhaled at normal levels
vital capacity
total amount of air ecxhaled after full inhalation
big breathe in and fast exhale
inspiration/exhilation reserve
the total amount of volume inhaled or exhaled minus the tidal volume
epidermis in leaf
- there is a upper and lower epidermis
- single layer of tightly packed cells
- contains stoma and gaurd cells
- when the guard cells have water they go turgid - open stoma
- when they have no water they go flaccid and close
- allows for oxygen and co2 in and out
- there is a waxy cuticle outside the epidermis wich is impermeable as protection
mesophyll tissue
- parenchyma cells (chloroplast) for photosynthesis
- palisade mesophyll, below the upper epidermis
- spongy mesophyll, large air spaces between cells for gas exhange
vascular tissue
- vascular bundles responsbily for substance transport
- veins in leaves
-roots in plant
waxy culticle
- stops water losss
- prevents gas exhange
adaptions in leaves
- stoma allow gas exchange in epidermis
- stoma clsoes at night
- stoma closes during
- air spaces allows for co2 and 02 diffusion
- spongy mesophyll has a large surface area of o and co2 to diffuse maintining co2 gradiets
- photosynthesis maintians gradients
transpiration
consequence of gas exchange when the stoma opens to give carbon dioxide for photosynthesis water vapour is also allowed to leave
advantages of transpiration
- cools the plant down
- uptakes minera;s from soi;
- water pressure increases `
air movement - transpiration
- more air movement, more transpiration
- the air outside is usually less concentracted than within the plant
- this increases concentration gradinent and water loss
- when air is still water accumulates there is a ‘local high humidity’ so less water loss due to concentration gradient
more wind, less water, more loss
less wind, more water, low concentration
temperature - transpiration
- more temperature, more transpiration, until the stomata closes
- more kinetic energy, bond break faster and evaporation happens faster and easer
- this leads to the closing of stomata
light intensity - transpiration
- more light, more transpiration
- stomata closes in the night and opens in the day
- when its open water is lost
- if all stoma are open and there is more light, there will be no effect
humidty transpiration
- more humidity less transpiration
- air surrounding has water
- no concentration gradient
- may reach equillibrium
determining stoma density
1) a sample of epidermis peeled off put in water on a slide and examined
2) nail polished on the leaf forming a cast of the surface
3) leaf is photographed and a micrograph is used for a stoma count
mm-2 mean number/area in feild view
