TOPIC 3: Passing It On Everywhere you look, there are examples of organisms that look just like their parents. How does this happen???

Reproduction Is ONE of the characteristics of living things Is ESSENTIAL to the survival of the SPECIES but NOT the INDIVIDUAL Reproduction can be either sexual or asexual

How are traits passed on? Traits are said to be inherited or heritable and are passed on in the genetic material (DNA)

Asexual Reproduction DEFINITION: Asexual reproduction occurs when only one parent supplies the information to the offspring A formation of a new individual from a SINGLE organism

Inherited traits are like the parents OFFSPRING LOOKS LIKE: Inherited traits are like the parents Looks IDENTICAL to the parent ORGANISM EXAMPLES: Common among bacteria and fungi

ADVANTAGES: No energy wasted in finding a mate Does not require a specialized cell or way of getting the gametes together Can occur rapidly (bacteria-20 min) Large numbers Good only in that type of environment

DISADVANTAGES: Cannot survive if the environment changes NO variation among species

Types of asexual reproduction Binary Fission Spore reproduction Budding Vegetative reproduction

Binary fission Many one celled organisms such as the amoeba reproduce asexually by binary fission. Binary fission: the first cell duplicates its organelles and then splits creating a second organism with a copy of the same genetic material

Asexual Spores Some fungi and mushrooms can reproduce asexually using spores. Spores are single celled, reproductive structures Usually spores are produced in high numbers to ensure at least some survive Some other algae produce zoospores which move with a tail-like structure

Budding In budding, an organism will grow a new group of cells near its base (BUD) and then the ____bud_____________detaches as a new growth to start a new organism b. Examples: Sea sponge

Asexual reproduction in Plants Plants don’t produce spores, but they still reproduce asexually. 1. Meristem Meristem cells are able to repair damage to the plants Meristem cells are also used for ‘cuttings’ when planting new plants. 2. Runners and suckers Runners are sent out by strawberry plants above ground Suckers are sent out by poplar trees and lilacs above or below ground

3. Tubers 4. Bulbs Potatoes and yams When they are put into the ground they will grow a new plant 4. Bulbs Onions and daffodils When put into the ground they will grow a new plant http://study.com/academy/lesson/asexual-plant- reproduction-vegetative-propagation-and-bulbs.html

Asexual plants – clones???? In asexual reproduction in plants, the offspring are clones (exact copies) of the parent. You may recall Dolly the sheep. She was the first organism to be successfully cloned. What do you think about cloning? https://www.youtube.com/watch?v=tELZEPcgKkE

Sexual Reproduction Definition: Offspring Looks like? Reproductive process involving two sexes or mating types and resulting in a combination of genes Offspring Looks like? Both parents supply genetic material so the offspring will display a combination of both parents

Organism Examples: Advantages: Disadvantages: Plants, Animals Get a variety of living things Disadvantages: Takes a lot of energy Needs to provide a way for gametes to meet Protect and nurture young Limited offspring

Sexual Reproduction in Plants Pistil – female reproductive part of the plant Consists of the ovary, style and stigma Stamen – male reproductive part of the plant Consists of the anther and filament Ovule – contains the female gamete Anther – contains the male gamete

Steps of Pollination 1. Pollen gets stuck to the stigma 2. Pollen tube grows to the ovule 3. Pollen grain (sperm) Travels to the ovule to fertilize egg 4. Zygote is formed and it undergoes many cell divisions to form an embryo 5. Embryo is supplied with food by one or two cotyledons - seed

Sexual Reproduction in Plants Plants have diverse reproductive strategies 35,000 spore bearing 700 species are gymnosperms (produce seeds in cones) 200,000 species of angiosperms (flowering plants) Some are self pollinating and some are cross pollinating

DEFINITON ADVANTAGES DISADVANTAGES Self Pollination - male and female gamete comes from the same plant Ensures pollination and SURVIVAL Obtain an “pure breed” or clone -No variation to survive in an ever changing environment Cross Pollination - Male and female gametes come from different plants Allows for variation and survival in the ever changing environment - Less chance to get pollinated (needs insects)

Avoiding Self Pollination Stamen and pistils mature at different times Stamen is shorter than pistils Wind-pollinated flowers usually bear the pistil and stamen in separate flowers Some have pistil and stamens on different parts of the same plant (corn)

Sexual Reproduction in Animals For sexual reproduction to be successful: Male and female gametes must arrive at the same time at the same place Zygote requires specific conditions to develop nutrients Moisture Warmth and Protection

Unite to form a ZYGOTE (a fertilized egg) What happens? ). Sexual reproduction combines: TWO _________________________ (sex cells = sperm, egg) to form ONE _________________________ (fertilized cell = a new individual A male sex cell is called a SPERM A female sex cell is called an EGG Unite to form a ZYGOTE (a fertilized egg)

Bacterial Conjugation Bacterial Conjugation is a PRIMITIVE form of sexual reproduction. Two parents are still involved. In bacterial conjugation, a connection is formed between two cells. A one-way transfer of genetic material from one cell to another can then occur

EXTERNAL FERTILIZATION - Most worms, many fish, and amphibians Sperm meets the egg outside of the body Moisture is needed for the sperm to swim Lots of energy is spent to produce large numbers of eggs and sperm INTERNAL FERTILIZATION -Insects, reptiles, birds, mammals and some fish and amphibians - Sperm meets the egg inside the body - Reduces the harsh climate and predators Provides a moist environment for the sperm to swim Smaller number of sperm and eggs needed

Interesting Tid-Bits Monotremes are mammals that lay eggs. Ie: Platapus and spinny anteater

Hermaphrodites can produce both egg and sperm Individuals can change their sex over time The female opossum gives birth to offspring that are smaller than a honeybee.