1. GROWTH PATTERNS a) sigmoid growth curve ( organism and population )
b) human growth curve
c) limited growth curve ( annual plants ) and unlimited
growth curve ( perennial plants )
d) isometric growth ( fish ) and allometric growth
( human organs )
e) intermittent growth curve ( arthropods )

2. By the end of the lesson the students should be able to:
22.3 Types of Growth Curves
Objectives 1
By the end of the lesson the students should be able to:
give the types of growth curves
describe the types of growth curves
give the example of organisms which growth pattern follow the growth curves

3. Organism that have a sigmoid growth curve are:-
Growth patterns
Sigmoid Growth Curves 2
Organism that have a sigmoid growth curve are:-
Individual organism / large size of multi cell plants / animals
Microorganisms population ( yeast, bacteria ) 3

4. Growth patterns
Sigmoid Growth Curves 3 4

5. Intermittent growth curve
Growth Patterns
The Patterns 1
patterns of growth vary from species to species
the patterns of growth in living multicellular organisms are:
human growth curve
vs.
allometric
isometric
limited
unlimited
vs.
Intermittent growth curve

6. human growth curve

7. Growth patterns
Human Growth Curves 2
In human, the growth curve after birth appears to consist of two sigmoid curves, with two main rapid growth phases, the infant phase and the adolescent phase.
A slower growth phase is known as the childhood phase can be found in between these two rapid growth phases.

8. Growth patterns Human Growth Curves 3 infant phase childhood phase
adolescent phase A B
C D 8

9. i. Prenatal growth ( before birth )
Growth patterns
Human Growth Curves 4
Human growth curve:
i. Prenatal growth ( before birth )
ii. Postnatal growth ( after birth ) 9

10. Growth patterns
Human Growth Curves 5
Prenatal growth
Postnatal growth

11. Growth patterns
Human Growth Curves
Prenatal growth 6
In embryos, the brain and the head will both start growth and development together in the early phase of life, while; 11

12. Growth patterns
Human Growth Curves
Prenatal growth 6
The complete development of hands and feet only occurs in the later phase. 12

13. Growth patterns
Human Growth Curves
Postnatal growth 7

14. Growth patterns Infant phase: Human Growth Curves8
Infant phase:
Very rapid growth rate
Irrespective in both male or female babies.

15. Growth patterns 2. Childhood phase : growth rate is slower.
Human Growth Curves 9
2. Childhood phase :
growth rate is slower.
beginning at the age of four,
the rate is slightly higher in boys than in girls

16. i.e. two years earlier than begins in males.
Growth patterns
Human Growth Curves
3. Adolescent phase: 10
growth rate is rapid.
in the earlier part of this growth phase, females demonstrate a more rapid growth rate
i.e. two years earlier than begins in males.

17. Growth patterns 3. Adolescent phase: Human Growth Curves11
At the later part of this growth phase, the male growth rate becomes higher than the female growth rate.
This difference results in the females attaining puberty at an earlier age compared to males.
Females attain puberty around the age of 12, while males attain puberty when they are about 14 years old.

18. most individuals would have attained maturity.
Growth patterns
Human Growth Curves 12
4. Adult phase:
growth rate is zero
most individuals would have attained maturity.
Males achieve this phase at the age about 18 while females at the age around 16.

19. growth rate is negative
Growth patterns
Human Growth Curves 13
5. Ageing phase
growth rate is negative
i.e. the body proportion will start to decrease starting from the age of 30.

20. Growth patterns
Human Growth Curves 13

21. Relative short life span
Growth patterns
Limited Growth Curves 14
The growth of an organism to a maximum fixed size, which depends on the type of the organism.
Relative short life span

22. Growth patterns A single Sigmoid growth shape Limited Growth Curves14
Growth is complete when the organism achieves its maximum size.
and then demonstrates the negative growth, senescence
A single Sigmoid growth shape

23. Growth patterns e.g. most plants and animals, including human
Limited Growth Curves 15
e.g. most plants and animals, including human

24. Growth patterns Limited Growth Curves17
Annual plant growth curve eg: Pisum sativum ( Pea plant )

25. Growth patterns
Limited Growth Curves 16
In annual plants, the sigmoid growth curve of dry mass versus time shows a small reduction in dry mass in the initial part of growth, due to seed germination.
During germination, food stored in the cotyledons is usually used up before the first leaves undergo photosynthesis.

26. Growth patterns Limited Growth Curves18
This loss of mass is later replaced when the first leaves develop and start photosynthesis.
Later, growth rate is very rapid, until it becomes constant at a later stage.
This rapid growth rate is maintained until the plant achieves maturity, after which the rate gradually reduces until it becomes zero.
e.g: pea plant

27. Growth patterns Unlimited Growth Curves19
Refer to non-stop growth over a relatively long life span
Example organisms demonstrate unlimited growth:
Obelia colonies,
coral reefs and
multiple season woody trees

28. Growth patterns
Unlimited Growth Curves 19
The growth curve for unlimited growth comprises a series of small sigmoid curves.
This type of curve shows that there is an increase in the mass and size every season.

29. Growth patterns
Unlimited Growth Curves 20
In plants that demonstrate unlimited growth, there is no fixed rate and the growth continues until enemies, natural catastrophe or diseases cause destructive effects on them.

30. Growth patterns Unlimited Growth Curves21
Unlimited growth curve ( perennial plants )

31. Growth patterns
Unlimited Growth Curves 22

32. Growth Patterns
Allometric Growth 23
Allo= Gk. different
The growth of an organism within which different organs grow at different rates from each other and from the overall growth.
involves the change in size and external
shape/ features of the organism

33. Growth Patterns involves the change in size and external
Allometric Growth 23
Allo= Gk. different
involves the change in size and external
shape/ features of the organism

34. Growth Patterns Allometric Growth24
It shows the correlation between the growth and development of the organism
e.g. in mammals: the growth rates of the lymphatic and reproductive tissues is different
i.e. the growth rates of both tissues are the highest at the different stages of development

35. Growth Patterns
Allometric Growth 25
the mammalian lymphatic tissues grows rapidly during the early childhood years
but during adolescence its growth rate is lower, why?
the mammalian reproductive tissues grows faster during the stage of adolescence, why?

36. This is because lymphoid tissues are required by a young
individual to give it natural immunity and defense againts
disease.This function is less needed during the adult phase.
The reproductive system only starts to grow and
develop during the adolescent phase.
Similarly, in embryos, the brain and the head will both
start growth and development together in the early
phase of life, while the complete development of hands
and feet only occurs in the later phase.

37. Growth Patterns
Allometric Growth 26

38. Growth Patterns
Allometric Growth 28
ALLOMETRIC GROWTH 38

39. Growth Patterns Isometric Growth29
The growth of an organism within the organs grow at the same rates with the other parts of the body.
the relative size of the organs is constant
i.e. the size of the organs increase, but the external features remain the same
e.g. fish, grasshoppers, cockroaches

40. Growth Patterns Isometric Growth30
not accompanied by a change in shape of the organism 40

41. Growth Patterns e.g. in grasshoppers Isometric Growth31
e.g. in grasshoppers
the relative proportion of the organs and whole body (size and shape remain the same

42. Growth Patterns
Isometric Growth 32
e.g. in a cucumber leaf

43. Intermittent Growth Curve
Growth Patterns 33
Intermittent Growth Curve
It is a discontinuous growth occurs in insects & other arthropods metamorphosis.
Growth is limited by the hard exoskeleton during certain periods until the ecdysis / moulting process takes place.
Then, growth occurs very suddenly at a rapid pace.(rate of movement)
Produces a step-like (intermittant) growth curve.
Each stage in between ecdysis is known as instar. 43

44. Intermittent Growth Curve
Growth Patterns 34
Intermittent Growth Curve
in arthropods e.g. insects
adult
5th instar
Ecdysis
3rd instar 44

45. Intermittent Growth Curve
Growth Patterns 35
Intermittent Growth Curve
Ecdysis:
also known as moulting
a process of changing the old exoskeleton of arthropods replaced with new soft layer and later becomes harden again.
occur periodically to allow growth and development.
during ecdysis, arthropod breathes in a lot of air
- body expands and break the old exoskeleton 45

46. Intermittent Growth Curve
Growth Patterns 36
Intermittent Growth Curve
Ecdysis:
when old exoskeleton is removed,
arthropod once again breathing in more air to increase it size before
newly formed layer of chitinious exoskeleton hardens.

47. 22.5 Ecdysis and Metamorphosis37

48. Metamorphosis

49. two types: complete and incomplete
Growth Patterns 38
Intermittent Growth Curve
Metamorphosis: Definition
a process of changing in shape which occur from one stage to the following stage in animals (insect).
two types: complete and incomplete
complete metamorphosis occur in holometabolic insects e.g. housefly, butterfly
incomplete metamorphosis occur in hemimetabolic insects e.g. cockroach grasshopper 49

50. Complete Metamorphosis39
larva 50

51. Incomplete Metamorphosis41 51