biology notes assignment

7/23/2019 Biology Notes Assignment

1/13

Biology Notes- Evolution of Australia Biota

- Distinguish between the processes if meiosis and mitosis in terms

of the daughter cells produced.

Meiosis MitosisDenition A type of cellular

reproduction in where the

numbers of

chromosomes are

reduced by half by the

separation of

homologous

chromosomes, producing

haploid cells!

A type of ase"ual

reproduction in where the

cells are divided into #

producing replicas with

the same number of

chromosomes in each

diploid cells

$ype of %eproduction &e"ual Ase"ual

'here does it occur( )umans, animals, plants, fungiAll organisms'hen cells are separated Di*erent +denticalrossing over es, mi"ing of chromosomesNo.unction /enetic diversity, se"ual

reproduction!

ellular reproduction for

growth and repair!Number of daughter cells haploid cells # diploid cellsNo! of Division # 0hromosome Number %educed by half &ame

reates &e" cells for female egg

cells or male sperm cells

Ma1es everything other than se"

cells

B 23+ &2423+ M& DA56


2/13

B 23+ &2423+ M& DA56


3/13

Mitosis

Interphase

- +nitialising cell division- ells prepare to divide 7 genetic materials double

Prophase

- 8airing of chromosomes- hromosomes thic1en and shorten! entrioles move to the opposite sides

of nucleus! Nucleus disappears and nuclear membrane disintegrates!

Metaphase

- Meeting of chromosomes in the middle- hromosomes arrange in the middle of cell, become attached to spindle

bres by centromeres! )omologous chromosomes do not associate!

Anaphase

- hromosomes are pulled apart- &pindle bres contract pulling chromatids to the opposite poles of the cell!

Telophase

- $wo cells- hromosomes uncoil! &pindle bres disintegrate! entrioles replicate!

Nuclear membrane forms! ells divide!

$he division of the cytoplasm 9yto1inesis: after mitosis is necessary to

ensure the cells have the correct number of chromosomes! Mitosis doubles

the numbers of chromosomes in a single cell so the cell divides in two to

preserve the chromosome number 9#n:!

Meiosis

B 23+ &2423+ M& DA56


4/13

Prophase- hromosomes separate into homologous pairs- Nuclear membrane brea1s down- rossing over occurs- hromosomes split into chromatids

Metaphase 1- hromosomes align in pairs towards the middle of

cell- hromosomes attached by centromere- &pindle forms at centre of cell ma1ing the

chromosomes pull away

Anaphase 1- hromosomes pairs separate, moves to opposite

end of cell

Telophase 1- # Daughter cells form- hromosome number halved

Cytoinesis 1- Daughter cells not identical, have half of the

original number of chromosomes

Metaphase !- hromosomes align at the centre- &pindle forms on the poles of the cell, pulling away

the chromatids

Anaphase !- hromatids move apart, to opposite poles

Cytoinesis !- daughter cells, not identical to each other, have

half the original chromosome number

B 23+ &2423+ M& DA56


5/13

Meiosis produces "ametes. "ametes are se" calls andhave half the normal number of chromosomes! Mitosis isthe process where the cell nucleus divides into #!+n multicellular organisms mitosis occurs in the body cells#somatic cells: for growth, repair and maintenance whilemeiosis occurs in the "onads #testes and o$aries% forse"ual reproduction!

&umans ha$e '( chromosomes nown as thediploid number #!n)'(* !+ pairs of chromosomes%.

,ach haploid cell produced by meiosis has !+chromosomes.

ariation in Meiosis- Crossing o$er occurs where the arms of

homologous chromosomes e"change geneticmaterial!

- $his occurs in the rst stage of meiosis- +n this process the ad;acent chromatids twist, split, and ;oin up with di*erent pieces!- New combinations are made, by lin1ed genes separated!- 5ariation is produced in se"ual reproduction

- Meiosis produced into haploid cells which show variation produced randomsegregation of the chromosomes pairs when crossing over!

- Due to all the variations between individual gametes, there are many potential

combinations that can occur to form a uent reproduction =ess fre>uent reproduction

B 23+ &2423+ M& DA56


6/13

0imilarities

Both male and female gametes re>uired for fertilisation

/ametes are provided with a watery environment where fertilisation will occur!

All possible fertilisations will grow to form uatic environment, allowing the gametes and young producedafter fertilisation to spread and live in large bodies of water!

Internal ertilisation- 6ccurs inside the body of the female in animalsfemale part of the plants!- .urther development of the new organism still needs water!

- Direct transfer greatly increases the chance of successful fertilisation!- $his is done by se"ual intercourse 9copulation:

- +n Cowering plants the male gamete is the pollen and once the pollen lands onthe stigma in the female part of the plant* the pollen goes down the ovary andthe male gamete is transferred and the ovum is fertilised!

- Male reproduction organ is called the stamen, with # parts the anther and thelament!

- Meiosis occurs inside the anther, resulting in the formation of haploid pollen grains!onsists of # haploid nuclei!

- .emale reproductive organ is called a pistil.onsisting of 0 or more Carpels found

at the centre of the Cower! +t consists of the 0tigma* style and o$ary! +nside the

B 23+ &2423+ M& DA56


7/13

ovary are ovules and this is where meiosis occurs resulting in the formation of haploid cells, one is the o$um #egg%.

Di/erence between seual and aseualreproduction #and conditions under which aseual reproduction is anad$antage%.

# or more 0 or more

B 23+ &2423+ M& DA56

Ase"ualreproduction

&e"ualreproduction

N

umberoforga

nisms

0

parentneeded

#

parentstomate

elldivisio

n

ellsdividebymitosis

,budding,ssion,orregeneration

ellsdividebyMeios

is

$ime

5eryshortperiodoftime

&everalmonths

/ame

tesarenotproduced

/am

etesproducedbyth


8/13

Number ofo*spring

Advantage No mate needed!Many o*spring

produced >uic1ly!$ime eFcient! =essenergy!0tableen$ironments $erylittle change.

/enetic variationin the o*spring!

6rganism isprotected! 2ni>ue!reates anevolution!

Disadvantage

No variation in theo*spring! /eneticdisease, o*spring willhave too!+f change happens, it

is hard for them tosurvive!

%e>uires bothse"es toparticipate! Moreenergy

E"amples &pider plants,bacteria, yeast,

;ellysh

Mammal, sh,reptiles, birds,insects

- Discuss the relati$e success of these forms of fertilisation in relation tothe colonisation of terrestrial and a2uatic organisms

- 6rganisms in a>uatic environments are successful in reproduction and survival asthey have adaptions suited to reproducing in this type of environment!

- $his means they have to completely rely on their environment in providing its waterfor fertilisation!

- 'ater protects the gametes from drying or heat stressed- dead!

- )owever, in order to survive on land, organisms needed to overcome thedependence on a>uatic environments for fertilisation by providing their

own enclosed moist environment within the female reproductive territory,protected from the dry terrestrial environment!

B 23+ &2423+ M& DA56


9/13

,ternal ertilisation

+n an a>uatic environment

- 6rganisms attempting to carry out e"ternal fertilisation in a>uaticenvironments are highly successful!

- /ametes do not dry out or dehydrate and they are able to survive inwater!

- But at the same time they must produce large amounts of gametes tocompensate from other factors such as predators, disease, and dispersalto unsuitable environments 9temperature, currents:!

+n a terrestrial environment 9land:

- 6rganisms attempting to carry out e"ternal fertilisation on land are notsuccessful at all due to the reliance upon a water environment forfertilisation and to transfer the gametes before they dry out!

Internal ertilisation

+n an a>uatic environment

- +nternal fertilisation is not necessary adaptation for most a>uatic speciesas there is already water for fertilisation!

- )owever it is successful in this environment!- .ewer gametes are re>uired because of the higher chance of the gametes

uniting!

+n a terrestrial environment

- +nternal fertilisation has only been possible on land because it does notneed water environment for fertilisation as they already is a moistenvironment for the transfer of gametes!

- 5ery successful as it is the mechanism for direct transfer of gametes whichavoids factors such as dehydration of gametes and loss by dispersal,therefore fewer gametes are re>uired!

- Environment is enclosed in a conned space, protecting from predationand disease!

- Describe some mechanisms found in Australian 3ora for4pollination

seed dispersal

aseual reproduction

#with reference to local eamples%

Pollination

B 23+ &2423+ M& DA56


10/13

- 8ollination is the transfer of pollen from the anther 9male part: to thestigma 9female part: in Cowering plants 9angiosperms: where fertilisationand reproduction can ta1e place!

- $here are # types of pollinationo &elf-pollination

- &elf-pollination is when the pollen matures and the anthers splitopen releasing the pollen which usually deposits in its ownstigma!

- +n many species the stigma and anthers of the Cower mature atdi*erent stages to prevent the self-pollination!

- E!g! Daisy and sun orchids self-pollinate!- .ertilisation occurs after self-pollination, the gametes will have

come from a single parent!o ross-pollination

- ross-pollination is when pollen from a CowerGs anther pollinatesa CowerGs stigma from a di*erent plant!

- /ymnosperms 9conifers: have only one method of cross

pollination, by wind!- 'ind pollination occurs when the anther release very light

pollen! And then large stigmas are well e"posed in order to catchthe airborne pollen!

- E!g! Native pines and grasses use wind pollination!- .ertilisation occurs after cross-pollination, the gametes will have

come from di*erent parents! $here will be a greater variationshown by the o*spring of plants because their parents aredi*erent!

0eed dispersal- After successful pollination and fertilisation of the Cower, the seed

develops- +t is an advantage for a plant to spread or disperse its seeds over a wide

distance!- $his prevents overcrowding from occurring within the same plant species

and increases the chances of survival in situations of environmentalchange such as re!

- &eed dispersed by wind, animal, re, water, or e"plosion!- 'ind- some seeds are designed to blow long distances li1e parachutes

9e!g! Dandelions have feathery parachutes to catch the wind and Coataway!:

- Animal- seeds in fruitsberries after being eaten, the seed passes out in

faeces which also provide nutrients to the plant! 9Mistletoe berries areeaten by mistletoe birds and they deposit by faeces in a new area!

- .ire- Eucalyptus only release their seeds after occurrence of a re,e"posing the capsules which release seeds for dispersal- advantages asthe seeds grow in uncompetitive environment!

- 'ater-seeds dropped by mangroves or water gums Coat in a protectiveshell along rivers to other areas where it will grow!

Aseual 5eproduction

B 23+ &2423+ M& DA56


11/13

- Ma1ing a new individual without the use of se" cells or gametes! 6nly oneparent is re>uired for the mitotic cell divisions to occur!

- &ome types of ase"ual reproduction areo Binary .ission - Bacteria

o Budding 7 oral and east

o

&pore formation 7 .ungi and mosso 5egetative propagation 7 roses 9plant cuttings regenerate:

o .ragmentation and %egeneration 7 &tarsh

o 8arthenogenesis 7 )oneybees and /ec1o

5egetative propagation is a form of ase"ual reproductionof a plant! 6nly oneplant is involved and the o*spring is the result of one parent! $he new plant isgenetically identical to the parent! New plants grow from parts of the parentplant!

8arthenogenesis is the development of unfertilised eggs into adults 9esp honeybees:! +n honey bees every egg laid by the >ueen will develop whether or not

they are fertilised!- %eproduction without fertilisation- e!g reptiles, li


12/13

,plain how the e$olution of these reproducti$e adaptations has increasedthe chanced of continuity of the species in the Australian ,n$ironment

- Aseual reproduction

- 0eual reproduction- ,ternal fertilisation- Internal fertilisation- Parental care- Plants 9self-pollination, etc!:

,ample for ,ternal fertilisation

$he chances of successful e"ternal fertilisation are increased by the synchronisation of the release

of gametes, reproductive cycles and the mating behaviours of each species! E"ternal fertilisation

and development means that parents spend less time loo1ing after the young, but more gametes

have to be produced to ensure that some eggs get fertilised! $he ad$antageof this method is the

high dispersal of young! $he gametes are thrown into the sea and fertilised eggs are carried away

to settle in an area di*erent to their parents! $his reduces competition for food and living space for

the parent generation, and allows >uic1 recovery of populations away from damaged areas!

Plants

&elf pollination- less energy in production, grow in areas where the 1inds of insectsanimals that

might visit are little or absent! $hese plants species contain high proportions of individuals,

adapted to their environment!

ross pollinators, such as insects, birds, mammals have become more e*ective and useful in

transferring pollen to the stigma for increasing population of that plant! As plants become more

speciali


13/13

- $hrough natural selection many Australian species have developedspecic adaptations to the environment, increasing the chance ofcontinuity and the successful survival of the species!

Bibliography

$utor5ista!com- N& 8earson 9#H0I:! Biology-ells-Ase"ual

%eproductionJ+nternetK 'orld 'ide! Available from

httpbiology!tutorvista!comcellase"ual-reproduction!html9Assessed

##HL#H0I:

&par1 Notes- BN 9#H0I:! +ntroduction to cell reproduction J+nternetK! Australia!

Available from httpwww!spar1notes!combiologycellreproduction9Accessed

0HL#H0I:

)artnell ollege- Nancy 'heat 9#H0:! Biology J+nternetK! America! Available

from httpwww!hartnell!edubiology-tutorials9Accessed 0HL#H0I:

Boo1 3ate,M and Oudith,B 9#HHH:! Biology J$e"tboo1K! Melbourne Australia

)einemann

Boo1 Diane Alford and Oennifer )ill 9#HH: Biology J$e"tboo1K Australia EPE=

MitosisMeiosis images from

httpbioap!wi1ispaces!comhQ0?QcollaborationQ#H0H-#H00

.lower image from httpimage!tutorvista!comcontentfeedu0H@Cower!;pg

B 23+ &2423+ M& DA56
http://biology.tutorvista.com/cell/asexual-reproduction.htmlhttp://www.sparknotes.com/biology/cellreproductionhttp://www.hartnell.edu/biology-tutorialshttp://bioap.wikispaces.com/Ch+13+collaboration+2010-2011http://image.tutorvista.com/content/feed/u1406/flower.jpghttp://www.sparknotes.com/biology/cellreproductionhttp://www.hartnell.edu/biology-tutorialshttp://bioap.wikispaces.com/Ch+13+collaboration+2010-2011http://image.tutorvista.com/content/feed/u1406/flower.jpghttp://biology.tutorvista.com/cell/asexual-reproduction.html

biology notes assignment

Documents