Download Erica-Mae N. Alim ABM-106 PERPETUATION OF LIFE Summary

Erica-Mae N. Alim
ABM-106
PERPETUATION OF LIFE
Summary.
Earth is inhabited by a wide variety of living things from smallest bacteria to the biggest animals.
plants are said to be one of the earliest inhabitants on earth. fossils imprints of some ancient ferns
serve as evidence of the existence of plants during prehistoric times. the survival of the present
day organisms rely on their abilities to survive and reproduce. organisms perpetuate through
reproduction and each organism is part of a reproductive continuum that goes back countless
generations.
the plant reproduction is the process of generating new plant individuals or offspring. plants
reproduce in two ways: the sexual reproduction and the asexual reproduction. Sexual reproduction
in plants involves the fussion of the parents gametes, which give rise to an individual that has the
genes of both parents. thus, the offspring is not genetically identical with either or both of the
parents. instead, it carries combined genes. sexual reproduction in plants starts with pollination.
pollination is the transfer of pollen from the anther to the stigma of the flower. the pollen grains
absorbs moisture in the stigma and sprouts, producing a pollen tubes that burrows deep into the
style of the pistil until it reaches the ovary. the two male gametes travel down the pollen tube into
the ovary. once inside the ovary, the two sperm nuclei enter the ovule. one sperm fertilizes the egg
and becomes the embryo, a diploid (2n). the other sperm fertilizes the two polar bodies and
becomes the endosperm, a triploid (3n). the endosperm is a nutrient-rich tissue which serves as
nourishments for the growing embryo. this process is called double fertilization. after fertilization,
the ovule becomes the seed and the matured or ripened ovary becomes the fruit. The Asexual
reproduction is a type of reproduction that creates genetically identical offsprings. the offspring
that arise from asexual reproduction can be considered clones. in most plants, asexual
reproduction is an advantageous adaptation. asexual reproduction in plants usually arises from the
vegetative parts (stem, roots, and leaves) of the plant. this is also called vegetative reproduction.
some plants gives rise to new plant using their modified or specialized stems, such as stolons,
tubers, bulbs and corms. stolons or runners are specialized stems of some plants such as the
strawberry. rhizomes are stems which grow horizontally under the ground. tubers, are used both
for starch storage and give rise to new plants. an example is potato plants. bulbs are underground
stems that gives rise to a new plant, such as in the case of onions and lilies. corms differs from the
bulb since it is also used for storage of food of the plant, sometimes reffered to as the bulbotuber.
corms give rise to new small corms in their nodes called cormels. some plants such as the
bryophyllum reproduce asexually on their leaves. new plants arise from their specialized leaves
that can later on be planted on the ground and become new individuals.
A flower consists of highly specialized male and female reproductive organs. the female
reproductive part of the flower or pistil has stigma, style, and ovary. the ovary contains the ovule
that has the egg nuclei. the stamen on the other hands, is the male part of the flower. it has the
anther that produces pollen grains, which contain the sperms.
The seed usually consists of a seed coat, embryo, and endosperm. The seed coat protects the
internal parts of the seed againts external factors. it also helps in the dormancy of the seed. The
endosperm serves as the food for the growing embryo. eudicot seeds such as beans, nango and
jackfruit have two cotyledons, while monocots like the corn, wheat and rise have one cotyledon.
The embryo has three parts: hypocotyl, epicotyl, and radicle. The hypocotyl becomes the lower
part of the stem. the radicle or the embryonic roots become the primary root and the first organ to
emerge in plants. The epicotyl becomes the upper part of the stem and gives rise to the shoot. after
the seeds are formed and become matured,they are usually scattered in the environment where
they can grow as new plant.this scattering of seeds is known as seed dispersal.this process is very
important in the survival and distribution of the plants speciea. there are different ways by which
seeds are dispersed.external factors such as wind,animals,humans,and water help in the succesful
dispersal of seeds.some seeds such as dandelion and mahogany have specialized structures
intended for easy dispersal.some have thorns or sticky surface that can cling on to sone
animals.most human and animals eat fruits.they throw the seeds on the ground where they become
new plants.germination is the early growth stage of a plant embryo.germination leads to
maturity,which leads to reproduction.
Reproduction in animals, like plants, animals also reproduce. by reproducing, an animal can be
sure that there is another individual of its kind that can take its place on earth when it dies. During
sexual reproduction in animals, a haploid sperm cell and a haploid egg cell unite to form a diploid
zygote. the process wherein a sperm and egg unite is called fertilization. the zygotes divides and
differentiates into an embryo. The embryo then grows and develos until the time of birth or
hatching. most animals exhibits cross-fertilization, meaning, fertilization involves two separate
individuals of the same species (a male and female) in reproduction. even earthworms which has
two sexes (hermaphrodite), do cross-fertilization. in the event that mating of two individuals is not
possible, for instance, when no other organisms is in the vicinity or the union of egg and sperm is
not possible, some species of animals undergo self-fertilization like that of the tapeworms in the
intestine. frogs, crabs, coral and most fishes undergo external fertilization. that is, meeting of
gametes does not happen inside the body of the female animal, but in the open environment or
outside the body. notice that most of them are aquatic animals, while others can stay in water (in
case of some amphibians). their aquatic or wet environment makes it possible for the sperm and
egg to meet for the fertilization process. these animals release large number of eggs and sperm to
increase the rate of successful fertilization. environmental factors such as predators, drying up of
the environment, abd flactuating temperatures may hinder the fertiluzation of some gametes. after
a successful fertilization, the zygote grows and develops. most vertebrates, such as birds, fish, and
most amphibians and reptiles, lay eggs. the egg is surrounded and protected by a tough membrane
or shells.
Human Reproduction,most fertilization happens inside the body of the female species,wherein the
male deposits the sperm in the female's reproductive organ during mating.this is called internal
fertilization.internal firtilization is said to be one adaptation of land animals which led to succesful
reproduction of species .the growth and development of the offspring happen in the uterus of the
mother.while inside the mother,the mother embryo is nourished through the umbilical cord.
Asexual reproduction in animals, some animals are also capable of asexual reproduction, which
usually occurs when sexual reproduction is not possible. asexual reproduction in animals occurs in
invertebrates and can be done through budding or fragmentation.
Budding involves the splitting of new individuals from an existing organisms by forming small
projections, called buds, from the parents body.
Fragmentation and regeneration is a type of asexual reproduction wherein a single parent breaks
into parts that give rise to new individuals. sponges, planaria, and starfish are examples of animals
that exhibit this type of asexual reproduction.
Parthenogenesis is a form of asexual reproduction in some animals that give rise to the growth and
development of an embryo without fertilization.
One role of reproduction is the transfer of hereditary materials from the parents of their offsprings.
genes are the molecular unit of heredity of all organisms. organisms that reoroduce through
asexual reproduction tend to grow in large numbers but have a disadvantage when it comes to
species vulnerabilities. asexually reproduced offspring tend to have very similar characteristics
from its parents. hence, they inherit even its way of adaptation. gene variation only happens in
simple mutation. one parent alone passes on a duplicate of all its genes to the newly-produced
individual.
Reaction.
I learned how the plants, animals and other organisms started to live and build their own family. i
also learned the process on how they grow using their own organ. In this chapter i learned and
know what the value of all the things that sorround us and also what we should do and should not
we do. because, if we do not determine the value and worth of each organism it can cause harmful
accident to all of us. many of us have the possibility to suffer any kind of disease and illness. so
that, in this chapter we should always remember that we must need to avoid destroying plants or
even kill any organisms around us, because, like us, they also have the potentials to live and
reproduce. all the lesson i got in this chapter., i use it in my everyday life and also i would share it
with my brothers and friends.