Reproduce (Asexual and Sexual) — Characteristics of Life

What Are Offspring?

All living things reproduce in one way or another. It's part of the life cycle of all organisms. Reproduction is the creation of offspring by a parent or parents. Think of offspring as children (or baby versions of the parents—whatever works for you).

Types of Reproduction

There are two types of reproduction:

1. Sexual reproduction
2. Asexual reproduction

Let's consider sexual reproduction first:

Now, let's compare this to asexual reproduction:

Key Vocabulary:

1. Organism
2. Sexual reproduction
3. Asexual reproduction
4. Offspring

Reproduction

All living things produce new organisms through reproduction. Two types of reproduction exist: sexual and asexual.

• Sexual: With another partner, requiring both a male and female sex cell
• Asexual: A single parent organism reproducing by itself

Sexual Reproduction

Sexual reproduction occurs when offspring is produced by the combination of two parents' genetic information. It is the common method of creating offspring in multicellular organisms. This type of reproduction helps evolution happen faster than asexual reproduction does due to the random combination of the parents' genetic information. Changes in a population, like behavioral isolation, greatly affect this mode of reproduction.

Asexual Reproduction

Asexual reproduction occurs when there is only one parent. This is most common for unicellular organisms. Asexual reproduction can happen through budding (a bud forms on the parent and grows into another organism) or binary fission. Because the offspring is basically a clone of its parent, it takes much longer for evolution to occur in the population.

On the small scale, different types of living things use a few kinds of cellular division, as shown below. Mitosis and binary fission are types of asexual reproduction, where one parent cell divides into two daughter cells. Meiosis is a kind of sexual reproduction where the genetic information from two parent cells are combined.

$$\color{#8925AE}{\text{Vocabulary Review:}}$$

$\color{#8925AE}{\text{Cell}}$ : Smallest unit of life

$\color{#8925AE}{\text{Reproduction}}$ : Sexual reproduction is when two organisms combine their genetic information to create a unique offspring. Asexual reproduction is when one organism creates a copy of itself

$\color{#8925AE}{\text{Development}}$ : How organisms grow and mature

$\color{#8925AE}{\text{Evolve}}$ : How a species changes over time

Types of Reproduction

One defining feature of living organisms is their ability to reproduce. Reproduction is the creation of a new living organism whose genetic material is sourced from one or more parent organisms.

There are two kinds of reproduction: asexual and sexual.

Asexual Reproduction

In asexual reproduction, the genetic material comes from one parent. The offspring are genetically identical to that parent. Examples:

• Fission, when single-celled organisms split evenly into identical offspring. Each offspring is identical to the original. Occurs in bacteria and most other prokaryotes.

• Budding, where a completely new organism grows out of the side of the parent organism. Occurs in flatworms, starfish, and yeast.

• Parthenogenesis, where a parent organism that usually reproduces sexually creates offspring using only its own genetic material. Occurs in some lizards, some bees, and some fish.

Sexual Reproduction

In sexual reproduction, two or more (but usually two) parents each contribute genetic material to create offspring through use of their sexual organs. The genetic material of this offspring is a mix of that of both parents. During this process, the genetic material can recombine in new ways. Examples:

• Sex in animals, which results in sperm cells penetrating an egg cell to create an embryo that will become an offspring animal.

• Sex in plants, where genetic material (pollen) from one plant mixes with that of another to create offspring plants. Sexual reproduction in plants is called pollination.

(Video) Asexual and Sexual Reproduction

by Amoeba Sisters

Reproduction is a defining feature of life. Without organisms reproducing, we wouldn't have all the critters we have on Earth now. Non-living things can't possibly reproduce. Rocks aren't having babies.

In this video, the Amoeba Sisters describe different kinds of reproduction and how it produces offspring.

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Summary

Asexual reproduction results in offspring that are genetically identical to the parent. This process occurs in some plants and most single-celled organisms. Some examples are binary fission and budding. However, not all plants reproduce asexually. They can also reproduce sexually.

Sexual reproduction involves the combination of gametes. Gametes have half the number of chromosomes as somatic cells. Another name for gametes is haploid cells. So, human gametes have 23 chromosomes (half of the normal chromosome number). When fertilization occurs, we end up with a zygote with 46 chromsomes. The fertilized egg then goes through cell division to make more cells, eventually forming a human. Gametes are made during the process of meiosis.

In asexual populations, reproduction occurs much more quickly, but evolution happens more slowly. In sexual populations, reproduction takes more time, but it also leads to more variety.