GRADE 9 - BIOLOGY

UNIT 4: REPRODUCTION

NOTE

DO NOT READ THE WORDS IN RED - ONLY FOR GRAPHICS PURPOSES

THE WORDS WRITTEN IN BLUE SHOULD BE READ AND USED IN

GRAPHICS

በዚህ የ Cells የመጨረሻ part video ላይ፣ የ Grade 9 ን እና Grade 10 ን cell

reproduction topics አንድ ላይ ለ entrance examination እንዲሆናቹ አድርገን
የምናቀርብላቹ ይሆናል።

Asexual reproduction እና Types of asexual reproduction የሚሉትን

Topics cover የምናደርግ ይሆናል።

OUTLINE:

 Introduction to reproduction
 Asexual reproduction
 Types of asexual reproduction
o Fission
o Fragmentation
o Budding
o Vegetative propagation
 Stolons (Runners)

በመጀመሪያውኑስ What is reproduction?

Reproduction

Reproduction is a fundamental biological process through which

organisms produce offspring of their own kind.

ዛሬ፣ የ grade nine Biology አራተኛ unit የሆነውን reproduction ን እንጀምራለን።

በዚህ unit ላይ mainly sexual reproduction ላይ focus የምናደርግ ሲሆን፣ ጨምረንም

Asexual reproduction ን እንማራለን።

[INTRO]

Reproduction is the process by which living organisms produce

new organisms or off-spring.
አንድ organism ራሱን የሚተካበት፣ ወይም reproduce የሚያደርግባቸው Asexual እንዲሁም
sexual reproduction የተሰኙ ሁለት modes አሉን።

Asexual reproduction is a mode of asexual reproduction where a

single parent produces offspring that are genetically identical to
itself, without the fusion of gametes.

Asexual reproduction ስንል፣ አንድ parent organism ብቻ involve የሚያደርግ፣ ማለትም

ምንም አይነት sperm ም ሆነ egg cells ወይንም gamete cells involvement የሌለበት፣

መጨረሻ ላይ ከ parent ጋር identical የሆነ genetic makeup ያለው offspring የሚፈጥርልን

type of reproduction ነው።

Asexual reproduction is a mode of reproduction that:

 Only involves one parent

 Produces offsprings that are genetically identical to the
parent
 Doesn't involve the use of gametes which are either egg or
sperm cells
 Each organism is capable of producing identical copies of
itself as soon as it becomes an adult.

የ asexual reproduction advantages የሆኑትን እንመልከት፣

No need for a mate or gametes, making it a simple and efficient process.

Offspring are genetically identical to the parent, ensuring all favorable

traits are passed on.

Rapid population growth in stable and favourable environments.

Plants that reproduce asezually often store large amounts of food, aiding
survival.

Disadvantages of asexual reproduction

Lack of genetic variation limits adaptability to changing environments

If the parent lacks resistance to a disease, all ffspring will also be

susceptible.

Overcrowding can occur due to lack of dispersal, leading to competition

for resources like nutrients, water, and light.

Examples of asexual reproduction

Bacteria reproduce through binary fission.

Hydra reproduces through budding

Starfish can regenerate from fragments

Plants like potatoes and strawberries reproduce through vegetative

propagation.

Types of asexual reproduction

Common in bacteria, algae, and protozoa.

The parent cell divides into two nearly equal parts through mitosis.

Before division, the nucleus is replicated to endure each daughter cell

receives an identical copy.

The nucleus divides repeatedly, and each daughter nucleus breaks away
with a small portion of the cytoplasm.

Results in the production of many daughter cells.

ይሄንን የ Asexual mode of reproduction ከሚከተሉ organisms መሃከል፣ bacteria፣

yeast፣ sharks, mosses እና liverworts በጥቂቱ ተጠቃሽ ናቸው።

ስለዚህም፣ አሁን ቀጥለን ደግሞ፣ ከ asexual reproduction types major የሚባሉትን፣

discuss እናደርጋለን፣

FISSION

ስለዚህም በመጀመሪያ ላይ የምናገኘውን፣ Fission ን discuss በማድረግ እንጀምር።

Fission is a reproduction process that involves the division of an

organism into two or more equal parts.

ይሄ type of reproduction በ bacteria፣ algea protozoa ላይ በብዛት observe

የሚደረግ ሲሆን፣

ለምሳሌ ይሄንን bacterial cell ወስደን ብንመለከት፣ በ reproduciton ወቅት በ binary fission፣
cell division አማካኝነት እንደዚህ ለሁለት equal parts ይከፈላል።

እነዚህ ሁለት separate parts each develop into individual cells that are
similar to the parent cell.

አሁን እንዳልነው፣ ለሁለት cell ከመሆን ይልቅ ለብዙ ቦታ የሚከፋፈል ከሆነ ደግሞ፣ Multiple fission
ይሰኛል፣ multiple fission is commonly observed among parasitic
protozoans such as malaria parasites.

FRAGMENTATION
ቀጥለን የምንመለከተው type of asexual reproduction የሆነው ደግሞ፣ Fragmentation
ይሰኛል።

Fragmentation is a common mode of asexual reproduction

involving the formation of spores.

ይሄ fragmentation process አንድን parent organism ለብዙ tiny parts fragment

በማድረግ ወይም ደግሞ በመሰባበር፣ እነዚህን tiny fragments ደግሞ separately independent
እንዲሁም ለ parent organism exactly identical ወደሆኑ parts የመቀየር ሲሆን፣

Plants fungi algea እንዲሁም የተወሰኑ animals ይሄንን አይነት reproduction ያካሂዳሉ፣

For instance, spirogyra የተሰኙት algea፣ በዚሁ fragmentation ሲሆን reproduce

የሚያደርጉት፣ እንደምናየውም፣

እነዚህ filaments የሆኑት algea በ fragmentation process ጊዜ፣ ለብዙ በመከፋፈል፣ each
filament ለ parent spirogyra cell genetically identical ወደሆኑ mature
filaments ያድጋሉ።

Even የተለያዩ multicellular የሆኑ worm species እንደዚሁ ለብዙ part በመከፋፈል፣
በተመሳሳይ መልኩ ለብቻቸው develop ማድረግ ይችላሉ።

BUDDING

ልክ እንደ fragmentation እና fission ሁሉ፣ Budding is a type of asexual

reproduction which involves an organism dividing into two
unequal parts

ይሄ type of asexual reproduction ልክ እንደ fission ሁሉ በ mitosis ቢሆንም divide

የሚያደርጉት፣ ከ fission በተቃራኒው ደግሞ፣ ለሁለት እኩል part ሳይሆን፣ አንድ አነስተኛ የሆነች
daughter cell directly ከ parent ላይ የሚገነጠልበት process ነው።

Budding is most commonly observed among fungal species such

as yeasts and some invertebrates use budding as a way of
asexual reproduction.

ስለ asexual reproduction ስናወራ፣ ሳንጠቅስ የማናልፈው ሌላኛው type የሆነው ደግሞ፣

Sporulation ነው።

SPORULATION

Sporulation is an efficient means of asexual reproduction that

allows fungi to colonize different habitats rapidly and effectively.

Fungi እንዲሁም ሌሎች organisms ይሄንን type of reproduction carry ion carry out
የሚያደርጉት፣ spores የተባሉ reproductive material produce በማድረግ ነው።

Spores are light weight reproductive structures that can be easily

dispersed by air currents, water or other means.
እነዚህ spores ባላቸው ከፍተኛ የሆነ ሙቀት እና lack of nutrient resistance ምክኒያት፣
ለ growth suitable የሆነ environment እስከሚያገኙ ጊዜ dormant ሆነው ለረጅም ጊዜ
የመቆየት ability አላቸው።

Suitable የሆነ environment encounter በሚያደርጉበት ጊዜ ደግሞ በቀላሉ እንዲሁም በፍጥነት፣

mycelliar networks በመዘርጋት እና አካባቢያቸውን exploit በማድረግ independently
develop ማድረግ ይችላሉ።

Spores are,

 Can remain dominant for extended periods of time until they

encounter a suitable environment.
 Resistant to adverse environmental conditions such as
extreme temperature or lack of nutrients
 Develop to form a mycellium which inturn exploits the
environment and produce other spores to reproduce by
itself.

ይሄንን seciton በዚህ ከጨረስን፣ ቀጥለን plants ለ asexual reproduction የሚጠቀሙባቸውን

methods ማለትም፣ የ vegetative reproduction ን concept cover የምናደርግ ይሆናል።

VEGETATIVE PROPAGATION

Vegetative propagation in plants involves asexual reproduction

through structures like roots, stems, buds and leaves, giving rise
to new independent individuals.

ይሄ የ asexual reproduction technique ደግሞ፣ based on the level of human

involvement፣ natural እና artificial vegetative propagation በማለት ለሁለት
እንከፍለዋለን።

በ natural vegetative propagation ስር፣ Stolons፣ Rhizomes፣ corm፣ tuber እና

bulb የተሰኙትን reproduction modes ስናገኛቸው፣

Artificially ደግሞ የሰው ልጆች፣ Grafting፣ cutting እና Layering ን በመጠቀም plant ስን

asexually reproduce እንዲያደርጉ ይረዳሉ።

በዚህ video ደግሞም፣ ከ natural vegetative propagation type ውስጥ አንዱ የሆነውን
Stolol ወይም ደግሞ Runners ን ለይተን እንመለከታለን።

STOLON

A stolon is a specialized stem structure in plants that grows

horizontally along the soil surface, which serves as a means of
vegetative propagation.

እነዚህ Stolons፣ generally በ strawberries፣ Ginger፣ mint፣ እንዲሁም በተወሰኑ

grasses ላይ prominent የሆኑ modes of reproduciton ናቸው።
እስቲ ይሄንን strawberry plant በማየት፣ የ stolon reproduction process ን ለመረዳት
እንሞክር፣

ይሄ parent plant፣ በስሩ በሚገኙ auxillary buds አማካኝነት፣ እንደዚህ stolons ወይም ደግሞ
runners የተሰኙትን stem like structures produce ያደርጋሉ፣

These stolons thicken at every two nodes and produce

adventitious roots and a new shoot።

የዚህ stolon root እና shoot የማውጣት attempt sucessful ከሆነ፣ ከስሩ ላይ ሙሉ ለሙሉ
developed የሆነ plant form በማድረግ ይሄ stolon eventually በመድረቅ ከአጠገቡ እንደዚህ
independent የሆነ ሌላ plant ይፈጠራል።

የዚህ reproduction main steps የሚባሉትን summarize ለማድረግ፣

Stolons originate from auxiliary buds

They Grow and extend along the surface of the soil and develop
nodes at every second node

The new plant gets independent from the parent plant.

በቀጣይ video ስንገናኝ፣ በ vegetative propagation ስር የተቀስናቸውን methods of

reproduction፣ parthenogenesis እንዲሁም Sexual reproduction in Humans
እንመለከታለን።