AP Bio- Interactions 2: Reproduction

Reproduction

Big Questions:

Why wouldn't you want more of us?

How are the reproductive systems of multicellular organisms adapted for sexual reproduction?

How do the constraints of the environment determine the adaptations in organismal reproductive systems?

How are the reproductive systems of animals and plants similar? How are the different?

General Points

Two Major Modes:

• Asexual (mitosis, binary fission, etc.)
• Sexual (n + n = 2n)

We'll mostly focus on sexual here.

Brief Review of Sexual Life Cycles

The "Sexual Handicap"...So why do it?

Fungi

Animals

Plants

Note: Plant Sex is analogous to Animal Sex (NOT HOMOLOGOUS!!!)

Mostly n, occasionally 2n

Mostly 2n, occasionally n

"Alternation of generations"

Parthenogenesis in Lizards

(sexual behavior still required!)

Preformationism...

Because everyone knows there's a little dude inside every sperm cell.

Asexual Reproduction in Aspen Trees

Sexual Reproduction in orchids

Asexual Reproduction in Anemones

Actually, This is a bit more typical for fungi:

Penicillium Mold

Many "Options"

How Much Parental Care?

Many plants reproduce asexually with ease

You are familiar with the reproductive structures of mushrooms (which is, to say, the "mushroom")

fruiting bodies producing spores!

Most plants require pollination for sexual reproduction

Sexual Reproduction in Sea Slugs

Evolutionary Trends in Plant Reproduction

Internal vs. External Fertilization

Sexual life cycle of a gymnosperm

Human Reproductive Systems

General Fungal Life Cycle

Need to know all structures and functions

Evolutionary history

Floral anatomy

Angiosperm gamete production

Spermatogenesis

Oogenesis

Sexual life cycle of an angiosperm

Hormonal control of ovum production

Actual Fungal Life Cycle Examples

Hormonal control of sperm production

What separates "sperm" from "egg"?

• size & motility (that's it!)

fuse with one pollen sperm to make triploid (3n) endosperm tissue for seed (food source)

An "idealized" monoecious flower.

Many angiosperms produce dioecious flowers.

Rhizopus, the Black Bread Mold (a zygomycete)

Oyster Mushroom (a basidiomycete or "club fungus")

fuse with other pollen sperm to make diploid zygote

Hundreds of millions/day

Begins at puberty

Ends at Death (viability does decrease in old age)

1 spermatagonium produces 4 mature sperm cells

Creates the pollen tube to deliver 2 sperm (from generative cell) to ovule

1/month

Begins at puberty

Ends at menopause (why?)

1 oogonium produces 1 mature ovum & 2 polar bodies

Contraception

More Pollinator Adaptations

Coevolution!

Mechanisms to prevent self-pollination

Pollinator Adaptations

a. dioecious plants have "male" and "female" flowers.

b. arrangement of styles and stamens can prevent self-fertilization (or at least minimize its chances)

Could there be other mechanisms? Examples?

structure & function!

Seed Development

Fruit Development

"Double Fertilization"

Why seeds?

Why fruit?

Seed Dispersal mechanisms

Stem Cells

Cloning

What gets fertilized, and why?

Germination

Stem cells are the regenerative cell populations in the body.

Different types vary in their degree of "potency."

At current, embryonic stem (ES) cells are the most potent.

Various therapies are in clinical trials, but none are widely available yet.

Various techniques have been developed to produce genetically identical offspring of parents.

These techniques have been used in all animal lineages

The clone is not completely identical to the parent (why?)

Legal restrictions prevent the reproductive cloning of humans in most of the world.

What are some of the differences in monocot and dicot germination?

Somatic Cell Nuclear Transfer-

The process used to create

Dolly & CC (the first cloned cat!)

Monocots vs. Dicots

Learn These!!!

Remember:

Monocots-

• One Cotyledon
• Grasses, mostly

Dicots-

• Two Cotyledons
• All other Angiosperms

Fun with Plant Reproduction

Make Sure You Can:

Any Questions?

Protoplasts

Artificial Selection: Teosinte vs. Maize

Cloning of Plants is so easy!!!

Compare sexual reproduction in fungi, animals, and plants.

Label all parts of the male and female reproductive systems and explain how they contribute to the functions of the systems.

Label all parts of a typical flower and explain how they contribute to sexual reproduction.

Demonstrate how reproductive technologies might have moral and ethical implications for society

Explain the causes of reproductive system disruptions and how disruptions of the reproductive system can lead to disruptions of homeostasis.

Explain how plant breeding technologies take advantage of the reproductive strategies of particular plants.