Why is there so much variation?

SEX

Today’s Tasks

• Sexual reproduction in plants

• Flower dissection

• Asexual reproduction

Reminder: Quiz tomorrow on scientific method, symbiotic relationships, heritability (everything except today’s stuff)

Textbook: pg 33-35

…whose seeds are enclosed in a protective covering

Why do I care?1. Seasonal allergies

Why do I care?

2. Oxygen

Why do I care?

3. An ovary a day keeps the doctor away

Plant Ovaries

Learning goal

• Examine and identify parts of a flower to understand their functions and importance for reproducing

Sexual Reproduction in Plants

• Just like with animal reproduction, there are male and female parts

Female part (Pistil)

Male part (Stamen)

Sexual Reproduction in Plants

• An angiosperm has an egg and sperm that will fuse:

– The male sperm is called pollen

– The female eggs are called ovules

Self-Pollination

• Basically plant incest

• Self pollination occurs when pollen is transferred to the ovule of the same plant

• Most angiosperms have ways to prevent self-pollination because it’s bad for the gene pool

Cross-Pollination• Occurs when the pollen of one plant is carried

by wind, water, or animals, to the stigma of another plant

Fertilization• occurs after pollination, when the sperm (pollen)

travels down the style and fuses with the egg (ovule)

• a new baby fruit is conceived

Bell Pepper Time Lapse

Click image to watch

Cross-Fertilization

• Occurs when pollen of one plant joins with the ovule of another plant.

• A baby plant will develop

• The offspring will be a genetic combination of both parents

Mom Dad

Click image to watch

Flower Dissection Lab

• Question: Can you locate and identify the reproductive structures of an alstroemeriaflower?

Asexual Reproduction

Making babies without having sex

• Only one parent

• No fusion of egg and sperm

• Offspring are identical to parent

We’ll talk about 4 types

of asexual reproduction

1. Binary Fission

• a single-celled organism splits into two new organisms

• Examples of organisms that do binary fission:

• many species of bacteria

• Amoebae

• Paramecium

• Streptococcus pneumoniae

2. Budding

• a bud forms on an organism, grows, and eventually breaks away to become a new organism independent of the parent

Examples: Yeast cell, hydra

3. Spore Production

• Similar to small seeds, spores are single-celledreproductive structures that give rise to new offspring

• Examples: Plants, algae, and fungi produce spores

– Spores are similar to seeds

4. Vegetative Reproduction

• No seed required; plants can reproduce from leaves, stems etc.

CuttingsTubers Runners

Plickers Practice

Why can’t mules have babies?

• https://youtu.be/6Hfelo_qAw0 (discusses sex cells and meiosis)