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Reproduction. Sexual vs Asexual. Plants and animals can reproduce in one of two ways Sexually Asexually. Sexual Reproduction. Sexual reproduction requires two individuals of opposite sex to exchange genetic material. Genetic material is exchanged using gametes
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Sexual vs Asexual • Plants and animals can reproduce in one of two ways • Sexually • Asexually
Sexual Reproduction • Sexual reproduction requires two individuals of opposite sex to exchange genetic material. • Genetic material is exchanged using gametes • Ex Sperm, egg, pollen and ovum • The gametes hold half of the genetic material of each parent. • When combined, they form a complete individual.
Asexual Reproduction This involves one individual replicating himself. This offspring contains the exact same genetic material as the parent. This offspring is considered to be a clone of the parent.
Reproduction in Plants • Plants are able to reproduce sexually and asexually. • Asexual reproduction • There are two methods of asexual reproduction
Asexual Reproduction • Budding • Plants create small copies of itself which then float off and can grow again. • Through stems • When the stem of a plant reaches the ground, it starts growing roots and creates a brand new plant.
Sexual Reproduction Sexual reproduction in plants involves pollen coming into contact with the ovum. Plants are usually both male and female at the same time. They have different parts that are male and female. We will discuss the different parts of the plants.
Stamen The stamen is the male part of a flower. The anther is where pollen is produced and stored in the flower. Pollen grains contain the male gametes (Plant sperm). Filament is the thin stalk that supports the anther.
Pistil Stigma is the sticky surface that captures the pollen. Style is the long thin tube that supports the stigma. Ovary is the swollen base of the pistil that contains the female gametes (ovules) Ovules are the female gametes.
Seed Dispersal Since plants cannot walk around, they need another way to spread their seeds. Too many plants in one area leads to competition and makes it harder for anything to grow. There are 4 methods which we will discuss.
Fruits Fruits can be used to spread seeds. As animals eat the fruits and the seeds pass through their digestive system. The seeds end up in their droppings further away from parent plant.
Barbs In the burdock fruits, the hooks attach themselves to passing animals. The seeds then fall off of the animal far away from the parent plant.
Wind Some plants, produce seeds with long silky filaments. Examples of this are dandelions and milkweed. Again, wind takes the seeds far away from the parent plants to spread.
Water Water can also take away seeds further down the river. This takes the seeds further away to avoid too much competition.
Reproduction in Animals Much like with plants, animals can reproduce asexually as well as sexually. Asexual reproduction is less common and happens more with simple organisms such as hydras and sea sponges. Sexual reproduction requires two individuals and is far more common.
Sexual Reproduction • There are 5 steps to vertebrate reproduction • 1- A male gamete fuses with a female gamete. • 2- This fusion produces an initial cell called a zygote that contains complete genetic material. • 3- The zygote divides and transforms into an embryo consisting of many cells. • 4- The embryo develops into a small animal. • 5- When the animal becomes an adult, it produces gametes and therefore also capable of reproducing.
Sexual Reproduction • In mating, two individuals of an animal species unite to combine gametes and achieve fertilization. • Fertilization occurs when a spermatozoon an ovum of a single species combine. • There are two types of fertilization: • External • Internal
External Fertilization As the name implies, this type of fertilization takes place outside the body of the female. This is done by most aquatic animals. In this type of fertilization, the spermatozoon and ovum are released into the water. After they meet, they develop and grow as normal.
Internal Fertilization Most species of land animals reproduce by internal fertilization. This involves the sperm meeting the ovum inside the female. Depending on the type of animal, the methods are slightly different.
Internal Fertilization Most reptiles and birds use a cloaca. Both males and females both have a cloaca and join them up to exchange sperm. All mammals have a vagina and penis where the penis gets inserted into the vagina to exchange the sperm.
Hermaphrodites Hermaphrodites are animals which have both male and female reproductive organs. Some animals start out as one sex and change during their lives. Some are both at the same time. In worms, who are both sexes, mate with another worm and exchange sperm. They both lay eggs too.
Human Reproduction In human reproduction, the spermatozoon are produced in the testicles. During intercourse, the sperm enters the vagina. The eggs are released by the ovaries. Fertilization takes place in the fallopian tubes.
