Happy Thursday!Happy Thursday!Please do the following:•pick up the handouts•pick up glue & a highlighter •have out your notebook

Reproduction Reproduction in Bacteria, in Bacteria, Plants and Plants and Animals Animals

Types of Reproduction:Types of Reproduction:ASEXUAL:Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells

Examples: Mitosis, binary fission, and budding

SEXUAL:Sexual reproduction involves two cells (egg & sperm) joining to make a new cell (zygote) that is NOT identical to the original cells

Example: Meiosis

Asexual Reproduction in Asexual Reproduction in BacteriaBacteria Prokaryotes such as bacteria divide into 2 identical cells by the process of binary fission

Parent Parent cellcell

2 identical daughter cells2 identical daughter cells

Chromosome Chromosome replicatesreplicates

Cell splitsCell splits

Sexual Reproduction of the Flowering Plant

Structure of the flower

Function of floral parts

Sepal : To protect the flower (and to prevent it from drying out

Petals : To attract insects to the flower for pollination

Function of floral parts

Stamen : To produce the pollen grains in the anthers. (Each pollen grain produces two male gametes/sperm, one of which can fertilize an egg cell)

Function of floral parts -Stamen

Anther

• Produces pollen

Filament

• Holds the anther in place

Function of floral parts

Pistil : To produce the ovules (Each ovule contains an egg cell inside an embryo sac)

Function of floral parts - Pistil

Stigma

• Where pollen lands after pollination

Style

• Pollen travels down this

Ovary

• Contains ovules (eggs)

Pollination

Transfer of pollen from the anther to the stigma of a flower of the same species

Pollination

Self pollination

• Transfer of pollen from an anther to a stigma of the same plant

Cross pollination

• Transfer of pollen from the anther to the stigma of a different plant of the same species

Petals brightly colored, scented with nectar

Small amounts of sticky pollen

Anthers inside petals Stigmas sticky, inside

petals

Animal (insect) pollination

Petals small, not colored brightly

Anthers outside petals Stigmas large, feathery

and outside petals Pollen large numbers,

light, dry and small

Wind pollination

Fertilization Fertilization is the

fusion of the male (n) and female (n) gametes to produce a zygote (2n)

The pollen grain produces the male gametes

Embryo sac produces an egg cell

Seed Formation in Flowering Plants • Sperm + Egg Zygote

• The zygote grows repeatedly by mitosis to form an embryo which is found within a seed

Fruit Formation

The ovule becomes the seed The ovary becomes the fruit

Fruit Formation

A fruit is a mature ovary that may contain seeds

The process of fruit formation is stimulated by growth regulators produced by the seeds

Fruit and Seed Dispersal

Need for dispersal Minimizes competition

for light, water etc. Avoids overcrowding Colonizes new areas Increases chances of

survival

1. Wind

2. Water

3. Animal

4. Self

Types of Dispersal

Germination The re-growth of the

embryo after a period of dormancy, if the environmental conditions are suitable

Water Oxygen Suitable temperature

Events in germination cease when the plants leaves have developed and the plant has started to photosynthesize

Review of the stages of sexual reproduction in plants…

4

Asexual Reproduction in PlantsAsexual reproduction

Does not involve gametes, flowers, seeds or fruits examples: binary fission, fragmentation, spore formation

and budding It involves only one parent and offspring are

genetically identical (have the same genetic content) to the parent

So what happens? So what happens? Part of the plant becomes separated from the parent

plant and divides by mitosis to grow into a new plant

Plant Reproduction via Spores Spore - a reproductive cell capable of developing into a new individual without fusion with another reproductive cell

Spores are different than seeds, they do not contain plant embryos or food stores

A structure called sporangia produce the very tiny spores When the sporangia break open, the spores are released and

dispersed by water or wind…if the spore lands in a suitable environment, it can grow into a tiny plant

Found in non-seed bearing plants such as mosses, algaes, and ferns

Fertilization: the fusion of two haploid gametes (sperm and egg) forms a diploid zygote

One set of chromosomes from mom combines with one set of chromosomes from dad to create a complete set of chromosomes The zygote is a The zygote is a

unique genetic unique genetic mixture of both mixture of both

parents.parents.

The zygote is a The zygote is a unique genetic unique genetic mixture of both mixture of both

parents.parents.

Sexual Reproduction in Animals (Humans)

Male and Female Reproductive Systems Male Reproductive System

Testes – gamete-producing organs Sperm travel from testes to the vas deferens and into

the urethra

Female Reproductive System Ovaries – gamete-producing organs Ovum (mature egg) moves from an ovary into a

fallopian tube Takes about 3-4 days to travel through the fallopian tube –

if the ovum is not fertilized within 24-48 hours it dies

If fertilization occurs, the fertilized ovum (embryo) develops in the uterus where it is provided nutritional support