topic 7 - genetics, populations, genetics and ecosystems

Question 1

genotype defneiton

Answer 1

the genetic constituition of an organism ( the allels it has for a gene )

Question 2

phenotype deff

Answer 2

the expression of the genes and its interactoin with the environemtn

Question 3

homozygous deff

Answer 3

a pair of homologoups chormozones carryinf the same allels for a single gene

Question 4

heterozygous

Answer 4

a pair of hologous chromozones carrying two different alles for a single gene

Question 5

rescessive allels

Answer 5

an allele only expressed if no dominant allele is present

Question 6

dominant allels

Answer 6

an allele that will always be expressed in the phenotype

Question 7

codominant deff

Answer 7

both allels are equally dominant and expressed in the phenotype

Question 8

multiple allels

Answer 8

more than two allels for a single gene

Question 9

sex linkage

Answer 9

a gene whos locus is on the x chromozones

Question 10

autosomal linkage

Answer 10

genes that are locasted on the same chromozone ( not the sex chromozone )

Question 11

epistasis deff

Answer 11

when one gene modifies or masks the expression of a different gene at a different locus

Question 12

monogybrid

Answer 12

genetic inheretence cross of a charachteristic determined by one gene

Question 13

dihybrid

Answer 13

genetic inheretence cross for a chaterchterisctis determined by two genes

Question 14

what does crossing over reuslt in?

Answer 14

new combos of allels in the gametes, this means the gametws in your punnet square may differ

Question 15

autosomonal linkage impact predicted gametes

Answer 15

allels for each gene linked on the same chromozome will be inhereted together so?

Question 16

three types of selectoin

Answer 16

stabalising
selectional
disruptive

Question 17

what is disruptive selection

Answer 17

indivuduals containing alleles coding for either extreme trait are more likely to survive and pass om htier allels, the allele frwuencey changed and more individuals possess the allsle for the extreme trait
contunided disruptive selectoin can ultimately lead to speciation

Question 18

speciation is…

Answer 18

the process that results in the creation of a new species

Question 19

speciation occurs when one og population of the same species become _ iscolted

Answer 19

repodcutively iscolasted
this iscolation means there are now teo popilations of the same species but can not breed together

Question 20

speciation can result in accumulation of…

Answer 20

differences in their gene pools to the extent that two populatoins would be unable to interbreed to make fertile ofspring
therefore clasified as two different species

Question 21

what is allopatric speciation

Answer 21

populations become seperated geographically leading to reporductive iscolation
e.g mountain ranges

Question 22

what is sympatric speciation

Answer 22

populations can be repoductively iscolated due to differenced in their behaviout
this could imact reproductivr behvaiour e.g it may cause indivuals to perfom different courtship rituals for indidivuals to be fertile at different times of the year

Question 23

what is genetic drift

Answer 23

the change in allele frequence within a population between generations
there will alwayds be genetci drift from one generatoin to the next but continual substantial genetic drift results in evolution
the smaller popuation is the bigger the impact allel feuwncy changed have proportionally
this is why evolution often occurs more rapidly in smaller populations

Question 24

popualtion defenition

Answer 24

group of orgnims of the same soecies living in the same habitat

Question 25

habitat deff

Answer 25

part of an ecosystem in wich paeticilar orgnaisms live

Question 26

community deff

Answer 26

all populations of diiferent species in the same area at the same time

Question 27

ecosystem deff

Answer 27

a comunity and the non living componants of an environment ( biotic and abiotic factors ) can range in size

Question 28

niche

Answer 28

an organisms role within an ecosystem including their position in the food web and habitat. each species occupied thier own niche goverend by adaptation to both abiotic and biotic factors

Question 29

carrying capscity deff

Answer 29

the maximum population size an ecosystem can support

Question 30

difference between abiotic and biotic factors

Answer 30

abiotic - non lving components of an ecosystem

Question 31

what are biotic factors

Answer 31

biotic fasctors and the living components of an ecosystem interacting together such as interspecific and intradpecific competion and predation can also affect pop size

Question 32

interspecific competiton

Answer 32

members of different soecies are in coetion for the same rescporce that is in limited suply

Question 33

intraspecific competiton

Answer 33

when members of the same speciies are in compettion for resepoces and a mate

Question 34

why do we sample?

Answer 34

more time effiecient if impletmented correctly it can be mroe accurate

Question 35

sampels must accurately represent the pop. this is ensured by:

Answer 35

random sampling in uniform areas to eliminrate bias live transects to examine a change over distance large number of samples ( 30+ )

Question 36

steps to a random sampling method

Answer 36

1. lie two tape measures at a right angle to creat a gridded area 2. use a random number generator to generate two co ordinates 3. place the quadrat and collect the data 4. repeat at least 30x and calculate a mean

Question 37

line transpects are used to estimate?

Answer 37

populatoin size when they are unevenley distrubuted e.g populations wich chasnge over distance

Question 38

common example of where we use line transects

Answer 38

sandy / rockey shores across a path or river

Question 39

two types of transect

Answer 39

belt transect - the quadrat is palced at every position along the tape measure interrupted transect - the quadrat is placed at unifrom intervals along the tape measure e.g every 5 mitres

Question 40

line transects method

Answer 40

1. place the tpae measure at a right angle to the shore line 2. place the quadrat every 5 mitres / every position 3. collect the data ( density / % cover / local freuqnecy 4. repet by plcing another 30 transects along the beach at right angled to the shore line