Reproduction!

• Asexual Reproduction– involves only 1 parent– offspring genetically

identical to parent– involves regular body

cells– It’s quick

• Sexual Reproduction– involves 2 parents– offspring genetic mix

of both parents– involves specialized

sex cells– It’s slow

Asexual Reproduction• Binary fission

– happens in bacteria, amoeba, some algae– one parent cell splits into 2 identical daughter

cells

Vegetative Reproduction

 

Budding•  In this method a bud like projection is

formed on the body of the organism. The bud then develops into a new

• individual. It then separates from the parent and forms an independent individual. Ex: Hydra, Yeast etc.

Budding

Buddinghappens in yeast, hydra, coralsparent produces a budbud gets detached and develops into offspring which is identical to parent

Plantlets

New plant can grow on the leaf on the parent plant.

Tubers

Tubers = enlarged part of underground stem that store food

Ex: Potatoes

Runners

Runners are side shoots which grow out from the parent plant.

Buds form at points along the runner and eventually these buds form roots and grow into new plants.

Examples: spider plant, strawberry

Cutting

They can be placed in moistsoil or water (and sometimesdipped in rootingpowder).

Cuttings are small pieces of stem with some leaves attached, the new plant grows from this.

Fragmentation

New organism from part of the parent

RegenerationRegeneration is when an organism can regrow a missing part.

Cloning

• Cloning is the production of 1 or more individual plants or animals (whole or in part) that are genetically identical to an original plant or animal.

• Some concerns are held for all forms of cloning, others are specific to one form or the other

Some Organisms do Both

• most plants that produce seeds (sexual reproduction) can also reproduce asexually by things like cuttings or runners

• this gives them an advantage for survival

sponges and hydra mosses

What is needed for Sexual Reproduction?

• Gametes: these are sex cells– Sperm Cell: holds the male DNA– Egg Cell: holds the female DNA

• Sex Cells only have ½ the set of chromosomes

• All other cells in our body are called autosomes and they have a full set of chromosomes.

Sexual Reproduction in Animals

Sexual Reproduction in

Plants

(Pistil)

Male Parts

Female Parts

pollen (male) + ovule (female) → single-celled zygote → multi-celled

embryo (contained in a seed) → new individual

Sexual Reproduction in Plants

• stamen is the male part and contains pollen

• pistil is the female part and contains ovule (eggs)

• pollen grains from the anther are transferred to the stigma by the process of pollination– self pollination (plant pollinates its own eggs)– cross pollination (pollen from one plant

pollinates another plants eggs)

Pollination

• flowers are designed to lure insects to help with the pollination process– also wind, animals, birds can transport pollen

Which is Better?It depends!

Asexual Reproduction• advantages

– does not require special cells or a lot of energy

– can produce offspring quickly

– in a stable environment creates large, thriving population

• disadvantages– limited ability to adapt– face massive die-off if

environment changes

Sexual Reproduction• advantages

– lots of variation within a species

– able to live in a variety of environmental settings

– able to adapt to changes in the environment

• disadvantages– needs time & energy– produce small

populations