DP Biology (first assessment 2025)

Test builder »

Question SPM.2.HL.TZ0.8c

Select a Test
Date May Specimen-2023 Marks available [Maximum mark: 4] Reference code SPM.2.HL.TZ0.8c
Level HL Paper 2 Time zone TZ0
Command term Describe Question number c Adapted from N/A
c.
[Maximum mark: 4]
SPM.2.HL.TZ0.8c
(c)

Describe the barriers that exist to hybridization between species.

[4]

Markscheme
  1.  courtship behaviour is often complex and unique to a species;
  2.  (at several stages in courtship ritual) rejection occurs if characteristic behaviour not exhibited;
  3.  species-specific egg fertilization;
  4.  compatibility of acrosome with vitelline layer;
  5.  inability of successfully attached wrong species sperm to develop continuity with egg membrane;
  6.  sterility of interspecific hybrids;
  7.  due to differences in chromosome number;

Syllabus sections