Unit 5 Section 4: Animal Reproduction and Fertilization

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Unit 5 Section 4: Animal Reproduction and Fertilization

The orange worm moth lays its eggs in nuts. When the eggs hatch, they eat their way out and destroy the nut, causing devastation to farmers who depend on the plants for their livelihood.
In 2009, 11-year-old Gabriel Leal experimented to determine which species of nut the moth prefers. While most scientists had previously told farmers that almonds were the most at risk, Gabriel repeatedly found that the moths would choose pistachios when given the option. These findings have helped farmers determine how to arrange and protect their fields

Multiple Choice

Germination will not happen unless a seed

• is dispersed far from the plant that produced it.

• absorbs water.

• uses its stored food.

• grows stamens and a pistil.

Multiple Choice

The stages of a plant’s life cycle are

• sporophyte and spore.

• sporophyte and gametophyte

• spore and gametophyte.

• egg and gametophyte.

Multiple Choice

The female parts on a plant are called

• pistils.

• stamen.

• metamorphosis.

• petals.

Lesson Objectives

• Discuss the ways animals can reproduce

• Compare asexual and sexual reproduction occurs in both vertebrates and invertebrates

• Compare and contrast external and internal fertilization

How do Animals Reproduce?

• All living things reproduce in some way

  • Reproduction is essential for the survival of a species

• Animals undergo either asexual or sexual reproduction to make more of their own species

What about Bacteria?

• Bacteria are not animals

• They do reproduce

• Mostly do asexual reproduction, where one bacteria divides to form two new bacterial cells

• Some types do a form of reproduction similar to sexual reproduction, but not quite the same

Asexual Reproduction

• Involves one parent creating an identical offspring

• Can occur in different ways

  • Budding: a new animal grows out of the parent and breaks off when full grown

  • Some species can grow a new individual from lost limbs

• Can be the only means of reproduction or occur along side sexual reproduction

Asexual Reproduction Advantages vs Disadvantage

• Advantages

  • One parent can quickly produce many offspring

  • Sometimes a mate is not available

• Disadvantages

  • Each individual is identical and the population can be easily killed off by a change in the environment

  • Takes more energy from one individual

Sexual Reproduction

• Two gametes give half of the genetic material to an offspring

  • DNA determines the physical characteristics, and offspring may not look exactly like parents

• Most Vertebrates need two parents in order to get both gametes

• In some species an individual can produce both gametes and reproduce

  • Not common, and can be harmful

  • Most still mate with another of the same species

Sexual Reproduction Advantage vs Disadvantage

• Advantage

  • Each individual is unique, helping the overall population survive

  • More opportunities for mutations in a population

• Disadvantage

  • Need a mate, which may not be available

  • Offspring take longer to grow and develop

Drag and Drop

Most vertebrates and invertebrates reproduce​

Placeholder

Drag these tiles and drop them in the correct blank above

Sexually

Asexually

Both Asexually and Sexually

Multiple Choice

Which type of reproduction requires a mate?

• Sexual

• Asexual

• Both Sexual and Asexual

Multiple Choice

True or False: Offspring from asexual reproduction have different DNA than the parents

• True

• False

Multiple Choice

Budding is a form of

• sexual reproduction.

• asexual reproduction.

• gestation.

• complete metamorphosis.

Reproductive Cycles of Invertebrates: Sponges

• Reproduce both sexually and asexually

  • Do not have separate sexes, and produce both gametes

    • Release Sperm into the ocean, which lands in another sponge and fertilizes an egg

  • Larva: the fertilized egg of a sponge

    • Is carried away by the water until it lands in a spot where it can grow

Reproductive Cycles of Invertebrates: Cnidarians

• Cnidarians: Phylum of aquatic animals containing jellyfish

  • alternate between two body forms

    • Polyp: younger life stage of cnidarians that looks like an upside-down vase

      • reproduce asexually by budding and separation

    • Medusa: Life stage of cnidarians that looks like an open umbrella

      • Reproduce sexually by releasing sperm

External Fertiliazation

• Fertilization can occur both inside and outside of the female body

• Many fish, amphibians, and aquatic invertebrates use external fertilization, outside of the body

  • Water protects eggs from drying out

  • Females release the eggs, then males release the sperm over them

Internal Fertiliazation

• All land animals use internal fertilization

  • Sperm is released directly into the female body

  • Some species produce hard-shelled eggs that develop

• for most mammals: the young develop inside the female's body until it can be born

  • Gestation Period: The Length of time between fertilization and birth

Fill in the Blanks

Draw

Draw the shape of the medusa stage in a cnidarian life cycle