l09 new species

8/12/2019 L09 New Species

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BAGAIMANA SPESIESBAHARU MUNCUL?

Apa asal usulbiodiversiti sekarang ?



“biodiversiti” – hasil proses evolusi

dan speciasi

HOW we define species also has amassive impact on our view of'biodiversity’ - the study ofTAXONOMY



kita boleh melihat perbezaan paten variasispesies dan cuba memahami bagaimana ia berlaku

Darwin explains evolution …..

Those animalsthat survive

and reproduce ……. are those animals

that survive

and reproduce ….



Proses Asas…….

tumbuhan dan haiwan menghasilkan banyakanak untuk pengekalan populasi

biasanya berlaku persaingan untuk mandiri

kerana sumber terhad

anak- anak mempunyai ciri-ciri berbeza

Individu akan cuba menyesuaikan diri denganpersekitaran.



Individu yang dapat menyesuaikan diridengan persekitaran akan dapat hidupdaripada yang tidak dapat menyesuaikan diri

individu ini akan membiak danmemindahkan sifat-sifatnya kepada generasi

seterusnya.

and so on……….



Andaian proses yang berlaku

kebanyakan speciasi di kawasan terasing(geografi)

speciasi berlaku di mana desakan untukpemilihan adalah tinggi (ie .hanya beberapaindividu hidup- individu dengan variasimemberi kelebihan persaingan



Ini berlaku apabila sumber (air, nutrien ?)terhad

Individu yang hidup merupakan pengasaskepada generasi seterusnya

kumpulan baru akan terpisah secara genetik,(terutamanya terasing secara geografi) dantidak boleh membiak antara satu sama lain akan

membentuk spesies baru Bagaimana ini berlaku dan bolehkah kita

lihat kesannya?



PATEN pada ARAS SPESIES

komuniti hutan hujan mempunyaikepelbagaian pada aras FAMILI tetapi beberapaspesies dalam setiap famili

Jadi komuniti hutan hujan mempunyaibanyak spesies, kebanyakan tidak berkaitanantara satu sama lain dan datang daripadafamili berbeza.



Hutan hujan



di kawasan tanah lapang, vegetasi

mempunyai kepelbagaian SPECIES yangtinggi tetapi hanya beberapa famili yang adaeg in W.A.

89 families

5 families = 56% of species

egProteaceae ( Grevil lea, Bank sia )

Myrtaceae ( Eucalyp tus , Lep tosp erm um )Mimosaceae ( Acacia )



on the sand plain north of Perth at Eneabba

in a 1m X 1m quadrat can get 48species

in a 10m X 10m quadrat can get 110species



Sand Plain north of Perth



- alpha diversity- species richness within a habitat

- species richness within forest, or swamp etc

- beta diversity- species difference between habitats

nearby quadrats might have only 60%species in common

- species difference between swamp area andadjacent forest

DIVERSITY PATTERNS



- gamma diversity- difference within habitats between regions

difference within rainforest habitat betweenOtway rainforest and East Gippsland rainforest

DIVERSITY PATTERNS



DIVERSITY PATTERNS



south west Western Australia has aremarkable number of species in a small area

high levels of species r ichness and

endemism

> 8,000 species, 75% endemic

the Fitzgerald River area alone has moreplant species than the whole of the British Isles

Case Study: the Western Australian flora



Fitzgerald River NP



GENUS NUMBER of SPECIES Acacia 400+Eucalyp tus 300+Grevil lea 200+Sty l id ium 150+

Melaleuca 150+Hakea 100+Caladenia 100+

there are some 'centres of diversity’ or“diversity hot spots”



Fitzgerald River1750+ species

Mt Leseur820+ species

Stirling Range

Murchison Gorge



plantdiversity“hot spots”



Eucalyp tus



often have largeor showy fruits



Banksia

26 21



Verticordia



Acacia



In W.A. there is high ' -diversity' (gamma-diversity)

ie variation ACROSS the landscape

even relatively close areas havedifferent suites of species

how did this diversity arise ?



EXPLAINING DIVERSITYvegetation types

forest

arid zone



divide W.A. into three rainfall zones

HIGH (800 - 1500 mm)

TRANSITIONAL (300 - 800 mm)

ARID

(< 300 mm)

decreasingrainfall



Arid Zone



nutrient poor soils

these are some of the least

fertile soils in the world(low P)

plants have evolvedmany adaptations to be ableto compete

proteoid roots,symbiotic relationships

the landscape has barely changed since thePermian



erosion of laterites resulted in mosaic ofsoil types

typically laterite 'islands' in a sea of salinevalley floors



adaptation to these nutrient poor soilshas resulted in 'adaptive radiation'

(each species adopts a different survival strategywhich reduces direct competition)

some individuals have shallow extensive roots

some have deep roots

some exploit the surface to target brief rainfall

eventssome have both deep roots and extensive shallow

roots



reducesdirectcompetition



plants growing together have different survivalstrategies



in the Transitional Rainfall Zone climatic changeresulted in significant rainfall fluctuations

mean !

“high”

rainfall

“low”rainfall year



FREQUENT and UNPREDICTABLE

environmental stresses for a long period

variable climatic conditions result in strong

selection pressure strong selection pressure

results in high levels of speciation



following a fire

CONDITIONS SEEDLING SURVIVALDrought 780 seedlings nearly zeroArtificial watering 90% survivalWet depressions 90% survival'Good' year 40% survival

strong selection acting on populations isolated bysoil type (“island” effect)

results in different species on different soil“islands”



SUMMARY

factors contributing to the development of highdiversity in W.A. are:

nutrient scarcity result of long period of environmental

stability and leaching

geographic isolation (eg by arid Nullarbor Plain)mosaic of landforms and soils

(small scale isolation and “island” effect)



cycles of strong selection pressure following disturbances such as

drought, fire 'flush-crash' cycles



so we can see that many of our ideasabout speciation are supported by this casestudy

read about some other well knownexample such as Darwin’s finches in thereferences !!



many species are now at risk of extinction due tofragmented habitat



composition of roadside patches is very variable



if we know that our biodiversity isdistributed across the landscape, no single

reserve can conserve all of the speciespresent in the region

every “patch” has a different suite of species

how many patches can we protect ?

with limited resources which patches willwe choose to protect ?

....see the prac exercises !!!!

l09 new species

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