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Natuurwetenskappe

Graad 8

Biodiversiteit: aanpassings en oorlewing

Module 23

Prehistoriese lewe

Vir miljoene jare was die enigste lewe op aarde klein mikroskopiese eensellige organismes. Sowat 700 miljoen jaar gelede het die regte diere soos jellievisse en sponse in die see verskyn.

Hulle het sagte liggame gehad maar omdat diere skulpe, tande en kloue ontwikkel het, kan ons vandag nog bepaal hoe hulle gelyk het. Hoe? Deur die bestudering van nuutontdekte fossiele.

Van die begin van die Kambriaanse tydperk of periode sluit die fossielfondse diere soos krokodille en haaie in.

Sommige diere het gou uitgesterf toe toestande verander het. Ander het aanpassings gemaak en het oorleef. Verskeie kere in die aarde se geskiedenis was daar massale uitsterwings.

Die aarde is biljoene jare oud.

Vind meer hieroor uit: Besoek www.ucamp.berkeley.edu/exhibit/geology.html

Net soos ’n horlosie in ure, minute en sekondes verdeel word, so kan die aarde se geskiedenis in vier groot blokke verdeel word. Ons noem dit EONS. Die eerste drie saam staan bekend as die Prekambriaanse tydperk. Ons inligting oor dié tydperk is skraps vanweë min fossiele wat oorgebly het en waarvan ons sou kon leer.

Die laaste tydperk staan bekend as die Proterosoïese eon. Dié eon het sowat 540 miljoen jaar gelede begin en word in vier eras verdeel.

Hierdie eras is in periodes verdeel wat elk tussen 2 en 80 miljoen jaar kon geduur het.

Aktiwiteit: begripstoets en navorsing

1. Wat dink jy is geologiese tyd?

2. Gebruik die sirkel om die indeling van geologiese tyd soos hierbo beskryf, voor te stel.

3. Wat sou die massale uitsterwings waarna in die stuk verwys word veroorsaak het?

4. Wat is fossiele?

  1. Hoe dink jy bepaal wetenskaplikes die ouderdom van die aarde? Vind meer uit oor koolstofdatering.

NAVORSING: KOOLSTOFDATERING:

6. Vind meer uit oor EVOLUSIE soos wat dit gedokumenteer is.

  • Onthou dat hierdie ’n sensitiewe onderwerp is en dat almal nie dieselfde sienings huldig nie. Dit is egter ’n wetenskaplike se plig om alle verskynsels en teorieë te ondersoek en sy gevolgtrekkings met ander te deel. Elke individu kan dan besluit of hy saamstem of nie. Neem dus ’n ingeligte besluit!

NAVORSING: EVOLUSIE:

  • Soek op google.com

Assessering van navorsing:

Kon jy enigiets uitvind oor koolstofdatering en evolusie?

[LU 1.2]

Assessering

LU 1

Wetenskaplike Ondersoek

Die leerder is in staat om met selfvertroue op weetgierigheid oor natuurlike verskynsels te reageer, en om binne die konteks van wetenskap, tegnologie en die omgewing verbande te ondersoek en probleme op te los.

Dit is bewys as die leerder:

1.1 ondersoeke kan beplan;

1.2 ondersoeke kan uitvoer en data kan insamel;

1.3 data kan evalueer en bevindinge kan kommunikeer.

Memorandum

Prehistoriese lewe

Aktiwiteit: begripstoets en navorsing

  • Berei voor – lees self op oor koolstofdatering en kry bronne oor evolusie
  • Ook massauitsterwings
  • Soek toepaslike videomateriaal

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
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Sherica
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Sherica
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Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
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Nancy Reply
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ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
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Rachael Reply
yes
Asali
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Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
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Damian Reply
China
Cied
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abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
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Porter
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Yasmin
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Cesar
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Ramkumar Reply
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Sravani Reply
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AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
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AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Natuurwetenskappe graad 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11049/1.1
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