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 )
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
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 )
Growth patterns Sigmoid Growth Curves 3
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
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 phaseand the adolescent phase. • A slower growth phase is known as the childhood phasecan be found in between these two rapid growth phases.
Growth patterns Human Growth Curves 3 infant phase childhood phase adolescent phase B A C D
Growth patterns Human Growth Curves 4 • Human growth curve: i. Prenatal growth ( before birth ) ii. Postnatal growth ( after birth )
Growth patterns Human Growth Curves 5 Prenatal growth Postnatal growth
Growth patterns Human Growth Curves 6 Prenatal growth • In embryos, the brain and the head will both start growth and development together in the early phase of life, while;
Growth patterns Human Growth Curves 6 Prenatal growth • The complete development of hands and feet only occurs in the later phase.
Growth patterns Human Growth Curves Postnatal growth 7
Growth patterns Human Growth Curves 8 • Infant phase: • Very rapid growth rate • Irrespective in both male or female babies.
Growth patterns 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
Growth patterns Human Growth Curves 10 • 3. Adolescent phase: • 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.
Growth patterns Human Growth Curves 11 • 3. Adolescent phase: • 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.
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.
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.
Growth patterns Human Growth Curves 13
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
Growth patterns Limited Growth Curves 14 • Growth is complete when the organism achieves its maximum size. • and then demonstrates the negative growth, senescence • A single Sigmoid growth shape
Growth patterns Limited Growth Curves 15 • e.g. most plants and animals, including human
Growth patterns Limited Growth Curves 17 Annual plant growth curve eg: Pisumsativum ( Pea plant )
Growth patterns Limited Growth Curves 16 • In annual plants, the sigmoid growth curve of dry mass versus time shows a small reduction in dry massin 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.
Growth patterns Limited Growth Curves 18 • This loss of mass is laterreplaced 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
Growth patterns Unlimited Growth Curves 19 • Refer to non-stop growth over a relatively long life span • Example organisms demonstrate unlimited growth: • Obeliacolonies, • coral reefs and • multiple season woody trees
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.
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.
Growth patterns Unlimited Growth Curves 21 Unlimited growth curve ( perennial plants )
Growth patterns Unlimited Growth Curves 22
Growth Patterns AllometricGrowth 23 Allo= Gk. different • The growth of an organism within which different organs grow at different ratesfrom each other and from the overall growth. • involves the change in size and external shape/ features of the organism
Growth Patterns AllometricGrowth 23 Allo= Gk. different • involves the change in size and external shape/ features of the organism
Growth Patterns AllometricGrowth 24 • 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
Growth Patterns AllometricGrowth 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?
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.
Growth Patterns AllometricGrowth 26
Growth Patterns AllometricGrowth 28 ALLOMETRIC GROWTH
Growth Patterns Isometric Growth 29 • 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
Growth Patterns Isometric Growth 30 • not accompanied by a change in shape of the organism
Growth Patterns Isometric Growth 31 • e.g. in grasshoppers • the relative proportion of the organs and whole body (size and shape remain the same
Growth Patterns Isometric Growth 32 • e.g. in a cucumber leaf
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 / moultingprocess takes place. • Then, growth occurs very suddenly at a rapid pace.(rate of movement) • Produces astep-like (intermittant) growth curve. • Each stage in between ecdysis is known as instar.
Growth Patterns 34 Intermittent Growth Curve • in arthropods e.g. insects adult Ecdysis @ 5th instar Ecdysis 3rd instar
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
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.
22.5 Ecdysis and Metamorphosis Ecdysis 37
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 metamorphosisoccur in holometabolic insects e.g. housefly, butterfly • incomplete metamorphosisoccur in hemimetabolic insects e.g. cockroach grasshopper
Complete Metamorphosis 39 larva