SPM Biology 2012

Question

4 . Diagram 4.1 shows the sequence of changes in a pond ecosystem.

Rajah 4.1 menunjukkan urutan perubahan pada ekosistem sebuah kolam.

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(a) Name process K and process L.

Namakan proses K dan proses L.

 

(b)(i) Explain how stage III is formed from Stage II through Process L.

Terangkan bagaimana Peringkat III terbentuk daripada Peringkat II melalui Proses L.

(ii) At stage III, farming activities are carried out near the pond. Explain how the farming activity affects the ecosystem.

Pada peringkat III, aktiviti perladangan telah dijalankan berhampiran kolam. Terangkan bagaimana aktiviti perladangan mempengaruhi ekosistem.

(iii) State two differences between Stage I and Stage IV.

Nyatakan dua perbezaan antara Peringkat I dengan Peringkat IV.

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(c) A group of students carried out an activity to estimate the population of plant P and plant Q in a school compound using the following procedure:

Sekumpulan pelajar telah menjalankan satu aktiviti untul menganggarkan populasi tumbuhan P dan tumbuhan Q di Kawasan sekolah menggunakan prosedur berikut:

  1. A quadrat (1m x 1m) is placed randomly at a site.

Kuadrat (1m x 1m) diletakkan secara rawak di Kawasan itu.

  1. Plant P and plant Q which are within the boundary of the quadrat are counted.

Tumbuhan P dan tumbuhan Q di dalam kuadrat dikira.

iii. Steps I and ii are repeated five times as show in Diagram 4.2

Langkah I dan ii ditulang lima kali seperti ditunjukkan dalam Rajah 4.2.

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(i) Record the total number of plant P and plant Q in the five quadrats into Table 4.

Rekod jumlah bilangan tumbuhan P dan tumbuhan Q dalam kelima-lima kuadrat ke dalam Jadual 4.

(ii) Based on the result in 4(c)(i), which plant is dominant?

Berdasarkan keputusan dalam 4(c)(i), tumbuhan manakah yang dominan?

(iii) Give one reason for the answer in 4(c)(ii).

Berikan satu sebab bagi jawapan dalam 4(c)(ii).

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Answer ( 1 )

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    2021-02-28T16:57:47+08:00

    4.a) Process K: colonisation

    Process L: succession

     

    b)i)-As humus and soil collects at the bottom of the pond, the environment becomes unfavourable for the submerged plants. (Stage II)

    -However, it is suitable for floating plants, thus the pioneer species (submerged plants) are replaced by floating plants via succession.  (Stage III)

    ii)Farming activities use fertilizer which contains phosphates and nitrates. When soil from the farming land is leached into the pond, the excess nutrients causes the growth of algae.

    -Eutrophication and algal bloom occurs. The entire pond surface gets covered in algae.

    iii)-In Stage I there is not much plant life while in Stage IV as more nutrients accumulate there are emergent plants.

    -In Stage IV there is more soil eroding and nutrients which accumulate at the bottom of pond compared to Stage I.

    -In Stage IV the ecosystem becomes covered more with terrestrial plant life compared to Stage I which has more of an aquatic ecosystem.

     

    c)i)P-16

    Q-5

    ii)Plant P

    iii)It is possible that the environment and the nutrients provided create a habitat which is more suitable for the growth of Plant P rather than Q thus there is a larger number of Plant P (dominant).

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