Animal Reproduction

Memory Check Answers: 1. Explain how certain animals can reproduce asexually. Give one example A mature individual will produce a bud that develops directly on the parent. When the bud is mature, it breaks off and becomes independent. Example: Sponges and Hydras

2. Why must the spermatozoa and ova combine in a moist environment? Both the male and female gametes are very fragile cells that will die if they dry out. Moisture also keeps the egg membrane more supple, which allows the spermatozoa to penetrate more easily. Lastly the spermatozoa can only move in a moist environment

3. What is the difference between: A) Mating and Fertilization Mating: when two individuals of an animal species unite to combine gametes Fertilization: When the male and female gametes combine B) Internal and External Fertilization External: Gametes combine outside the bodies of both parents Internal: Spermatozoa enter the female and migrate to the ovum or ova C) A Cloaca and a Penis Cloaca: Where sperm, urine and feces are released Penis: Where sperm and urine are released

4. During a full moon, the entire population of a colony of sea anemones release their spermatozoa and eggs at the same time. Why? This helps increase the probability that the eggs will be fertilized since there will be more spermatozoa present

5. Turtles lay hundreds of eggs at a time 5. Turtles lay hundreds of eggs at a time. Birds usually lay fewer than 10. How can you explain the difference. When turtles hatch, they are able to find their own food and defend themselves; they do not require further parental care. When birds hatch they must be fed, protected and taught how to fly so mothers could not handle too many at one time

6. Describe the fertilization process of hermaphrodites. Both members of the species produce both an egg and sperm. When they mate each injects semen into the genital opening of the other to fertilize the other’s egg. They cannot “self-fertilize”

Reproduction in Animals Asexual Reproduction: A single living organism that can produce one or more identical individuals Sexual Reproduction: The combination of male and female gametes, each of which contain half of the genetic material necessary to the future offspring.

Gamete: The male or female reproductive cell that can unite with another, similar cell from the opposite sex, through a process called fertilization Sperm: The male reproductive cell, which includes a “tail” for movement (the whole structure is called a spermatozoa) http://www.youtube.com/watch?v=6rauO_M9tb4

Ovum: The female reproductive cell, the plural is “ova” Ovum: The female reproductive cell, the plural is “ova”. Commonly called an egg. http://www.youtube.com/watch?v=2-VKgdhfNpY&feature=related

Steps of Vertebrate Reproduction 1. Male gamete fuses with a female gamete 2. Fusion produces a cell called a zygote that contains complete genetic material 3. The zygote divides and transforms into an embryo with many cells

4. The embryo develops into a small animal 5. When the animal becomes an adult it will produce gametes and reproduce

Conditions for Sexual Reproduction 1. Male and female gametes must be at the same place at the same time 2. The zygote must obtain the nutrients and protection it needs to survive including warmth and moisture

Oviparous: Lays eggs- reptiles, birds, amphibians, insects and fish Viviparous: Fertilized ovum develops completly inside the mother’s body- almost all mammals Ovoviparous: Produce eggs but do not lay them, instead keep them inside their body- snakes