Reproduction in Organisms Video Lecture | Biology Class 12 - NEET

0:0:0: did you know that a single queen bee has
0:0:2: the incredible ability to lay up to 2000
0:0:4: eggs per day
0:0:6: Yes you heard it right two thousand
0:0:9: that's equivalent to laying her own body
0:0:12: weight and eggs every day
0:0:14: meanwhile us humans can only hope to
0:0:17: reproduce one progeny at a time
0:0:20: so now buckle up because we are about to
0:0:22: dive into the world of reproduction and
0:0:25: explore the diverse ways in which
0:0:26: different organisms reproduce and the
0:0:29: amazing mechanisms they use to pass on
0:0:31: their genes and ensure the survival of
0:0:33: their species
0:0:35: so in this video we will cover the
0:0:38: definition and purpose of reproduction
0:0:40: lifespan of organisms basic features of
0:0:43: reproduction and all the modes of
0:0:45: reproduction
0:0:47: let's first see what is reproduction
0:0:50: so it is a fundamental biological
0:0:52: process that ensures the continuity of
0:0:55: Life on our planet
0:0:57: but have you ever wondered what is the
0:0:59: purpose of reproduction
0:1:1: what is the reason for organisms to
0:1:3: engage in the process of reproduction
0:1:6: it's crucial for several reasons
0:1:8: firstly it maintains the continuity of
0:1:11: species
0:1:13: secondly it maintains the population of
0:1:15: young adult and aged individuals
0:1:19: thirdly it introduces variations in
0:1:21: organisms which are essential for
0:1:23: adaptations and evolution
0:1:26: finally life exists on Earth due to
0:1:29: reproduction in organisms
0:1:31: if you want to learn more about how
0:1:33: living things reproduce check out the
0:1:35: awesome eduriff notes
0:1:37: these notes are written in a way that's
0:1:39: easy to understand and they follow the
0:1:42: ncrt closely as well which builds your
0:1:44: confidence even more
0:1:46: let's talk about something really
0:1:48: interesting that is the connection
0:1:50: between an organism's lifespan and its
0:1:53: ability to reproduce
0:1:55: reproduction is essential for
0:1:57: maintaining the continuity of species
0:1:59: but did you know that an organism's
0:2:1: lifespan plays a critical role in
0:2:3: achieving this goal
0:2:5: it's true
0:2:7: so let's first learn what exactly is
0:2:9: lifespan
0:2:11: it's the period from an organism's birth
0:2:13: to its natural death
0:2:15: and let me tell you the lifespan of
0:2:18: organisms varies widely from just a few
0:2:20: days to thousands of years
0:2:22: imagine being a butterfly and living for
0:2:25: only one to two weeks
0:2:27: or being a banyan tree and living for
0:2:30: thousands of years you'd be the oldest
0:2:32: thing in the neighborhood
0:2:33: but here is the kicker in general
0:2:35: organisms have a limited lifespan which
0:2:38: means they can only reproduce for a
0:2:40: certain period
0:2:42: as an organism ages its reproductive
0:2:45: capacity gradually declines and
0:2:47: eventually it becomes unable to
0:2:49: reproduce altogether
0:2:51: so the timing and frequency of
0:2:54: reproduction are crucial for the
0:2:56: survival and propagation of a species
0:2:58: now coming back to the reproduction part
0:3:0: the process of reproduction involves
0:3:3: several basic features that are common
0:3:5: to all modes of reproduction
0:3:7: synthesis of RNA proteins and
0:3:10: biochemicals necessary for new cell
0:3:12: tissue production
0:3:14: DNA replication to transmit genetic
0:3:17: information to newly formed cells
0:3:20: cell division to produce daughter cells
0:3:22: for growth and specialized cell
0:3:24: production
0:3:25: growth of cells to develop mature
0:3:27: reproductive cell structures
0:3:30: formation of reproductive units gametes
0:3:33: or spores through sexual or asexual
0:3:35: reproduction
0:3:37: formation of new individuals from
0:3:39: reproductive units through sexual or
0:3:41: asexual reproduction mechanisms
0:3:44: now as we know reproduction is a process
0:3:47: by which living organisms produce new
0:3:50: individuals of the same species
0:3:52: this can be achieved through to main
0:3:55: methods a sexual reproduction and sexual
0:3:58: reproduction
0:3:59: and let's talk about these one by one
0:4:2: talking about asexual reproduction it
0:4:5: involves one parent and creates
0:4:7: genetically identical Offspring seen in
0:4:10: simpler organisms like bacteria and some
0:4:12: plants
0:4:13: this is achieved through processes like
0:4:16: budding fragmentation and
0:4:18: parthenogenesis Etc
0:4:20: for example an amoeba divides through
0:4:22: binary fission creating to identical
0:4:25: daughter cells
0:4:27: sexual reproduction requires to parents
0:4:30: in this male and female reproductive
0:4:33: cells combine to form a new individual
0:4:36: it is seen in most animals and some
0:4:38: plants like humans dogs cats and
0:4:41: flowering plants
0:4:43: now I know what you're thinking
0:4:46: why not all organisms reproduce with
0:4:48: asexual reproduction if it's simple and
0:4:51: involves a single parent only
0:4:53: wouldn't that be easy if there is no
0:4:55: sexual reproduction well my friends
0:4:58: sexual reproduction ensures genetic
0:5:0: diversity among Offspring which is
0:5:3: essential for adaptation and evolution
0:5:6: so there you have it
0:5:8: a sexual and sexual reproduction may be
0:5:11: different but they both have their
0:5:13: unique advantages
0:5:15: now let's explore the different types of
0:5:18: asexual reproduction
0:5:20: it can take various forms including
0:5:22: budding fragmentation and
0:5:24: parthenogenesis
0:5:26: first up we have budding no not the kind
0:5:29: you do with your bestie but the one
0:5:31: where Offspring literally grow on their
0:5:33: parents body like a strange growth
0:5:36: to understand how budding Works let's
0:5:39: take an example of a Hydra
0:5:41: hydras are fascinating creatures that
0:5:44: have a tubular body with a crown of
0:5:46: tentacles at one end
0:5:48: during budding a small bulge or Bud
0:5:51: develops on the body of the Hydra
0:5:54: this bird grows and develops into a
0:5:57: miniature version of the parent organism
0:5:59: as it grows it develops all the
0:6:2: necessary structures such as a mouth
0:6:4: tentacles and a digestive system
0:6:7: once the new individual is fully formed
0:6:10: it detaches itself from the parent
0:6:12: organism and goes off to lead its own
0:6:15: independent life
0:6:17: this process can occur repeatedly
0:6:19: resulting in the formation of a cluster
0:6:21: of individuals that are genetically
0:6:23: identical
0:6:25: interestingly budding is not limited to
0:6:27: Hydra alone
0:6:29: it is also observed in other animals
0:6:32: such as corals sponges and some species
0:6:35: of insects
0:6:36: in Plants budding can occur in the form
0:6:39: of vegetative propagation where new
0:6:41: individuals develop from the stems or
0:6:44: leaves of the parent plant
0:6:46: the next process we will discuss is
0:6:49: fragmentation which involves the
0:6:51: separation of a parent organism into
0:6:53: smaller pieces Each of which can develop
0:6:55: into a new individual organism
0:6:58: this is a form of asexual reproduction
0:7:1: where the organism essentially divides
0:7:3: into multiple pieces Each of which can
0:7:5: grow and develop independently
0:7:8: to better understand fragmentation let's
0:7:11: take the example of a planarine a type
0:7:13: of flatworm that lives in fresh water
0:7:15: habitats
0:7:17: planarians are fascinating creatures
0:7:19: that can regenerate their entire body
0:7:22: from just a small piece of their body
0:7:24: when a planarian is cut into two or more
0:7:27: pieces each piece can regenerate into a
0:7:29: complete genetically identical
0:7:31: individual
0:7:33: interestingly fragmentation can also
0:7:35: occur naturally in some organisms such
0:7:38: as in the case of starfish
0:7:40: starfish have the remarkable ability to
0:7:43: regenerate their limbs allowing them to
0:7:45: survive attacks from predators or other
0:7:48: environmental stressors
0:7:50: and at the end let's discuss
0:7:52: parthenogenesis it is a fascinating form
0:7:55: of asexual reproduction that occurs when
0:7:57: a female organism produces offspring
0:8:0: without the need for fertilization by a
0:8:2: male
0:8:3: this process is observed in many species
0:8:6: including insects fishes reptiles and
0:8:9: even some birds
0:8:11: parthenogenesis occurs when an egg cell
0:8:13: is stimulated to begin developing into
0:8:15: an embryo without being fertilized by
0:8:18: sperm
0:8:19: in some species this process can occur
0:8:22: naturally while in others it may require
0:8:24: specific environmental or genetic
0:8:27: triggers
0:8:28: to better understand parthenogenesis
0:8:30: let's take the example of the whiptail
0:8:32: lizard
0:8:33: whiptail lizards are an all-female
0:8:36: species that reproduce through
0:8:37: parthenogenesis
0:8:39: during the reproductive process the
0:8:42: lizards produce eggs that are
0:8:43: genetically identical to themselves
0:8:45: without the need for fertilization by a
0:8:48: male
0:8:49: this type of asexual reproduction can be
0:8:51: helpful in certain circumstances such as
0:8:54: when males are scared or when females
0:8:56: are under stress
0:8:58: it also has the potential to increase
0:9:0: genetic diversity within a population
0:9:2: which can be advantageous in the long
0:9:5: run
0:9:6: now coming to the second method of
0:9:8: reproduction that is sexual reproduction
0:9:11: it is the process by which offspring are
0:9:14: produced through the combination of
0:9:15: genetic material from two individuals of
0:9:18: opposite sexes
0:9:19: in humans sexual reproduction involves
0:9:22: the union of a sperm cell from a male
0:9:24: and an egg cell from a female resulting
0:9:27: in the formation of a zygote which will
0:9:29: eventually develop into a new individual
0:9:32: the process of sexual reproduction can
0:9:35: be divided into three main stages
0:9:37: pre-fertilization fertilization and post
0:9:40: fertilization
0:9:42: pre-fertilization includes the formation
0:9:44: and transfer of gametes sperm and egg
0:9:47: cells in animals and also involves
0:9:49: pollination in plants
0:9:52: fertilization is the fusion of sperm and
0:9:54: excels resulting in the formation of a
0:9:56: zygote with a unique set of genetic
0:9:58: traits
0:10:0: post-fertilization involves the
0:10:2: development of the zygote into an embryo
0:10:4: which develops into a fetus in animals
0:10:6: and a mature plant in plants
0:10:9: this phase includes cell division
0:10:11: differentiation and organ formation in
0:10:14: animals and Seed formation in plants
0:10:17: these three phases are really important
0:10:19: from the need exam point of view so
0:10:22: focus more on these and go through
0:10:24: adheriff documents of these topics
0:10:27: overall sexual reproduction is essential
0:10:30: for the survival and evolution of most
0:10:32: species on Earth and has played a key
0:10:34: role in shaping the diversity of Life on
0:10:37: our planet
0:10:38: in conclusion reproduction is a vital
0:10:41: process that enables the continuity of
0:10:44: species and the diversity of life on
0:10:46: Earth
0:10:47: understanding the basic features and
0:10:49: modes of reproduction is critical for
0:10:51: various Fields including evolutionary
0:10:54: biology ecology and genetics
0:10:57: we hope this video has provided you with
0:11:0: a better understanding of the
0:11:1: fundamentals of reproduction in
0:11:3: organisms
0:11:5: now here is a secret on how you can
0:11:7: study effectively with the edurev app
0:11:10: you can learn with chapter notes watch
0:11:13: video lectures and solve ncrt based McQ
0:11:16: tests of this chapter on eduriff
0:11:19: and this is available not just for one
0:11:22: but all the chapters of class 11 and 12
0:11:24: biology and much more for your need
0:11:27: preparation
0:11:28: thank you for your attention