Flowers Honor

Nature Study

Requirements

  1. What is the large group of plants that has flowers?

    Answer: The large group of plants that has flowers is that of the ANGIOSPERMS, from the Greek 'angeios' (container) + 'sperma' (seed), referring to the unique feature of producing seeds protected inside a fruit formed by the mature ovary. — Angiosperms emerged in the Cretaceous period (about 140 million years ago) and dominated terrestrial flora through their coevolutionary relationship with pollinators; another group with seeds (gymnosperms: pines, cypresses) does NOT produce flowers or fruit — a fundamental taxonomic difference.

  2. What is the function of a flower in a plant?

    Answer: The main function of the flower is the REPRODUCTION of the plant — it is the reproductive organ of the angiosperms. In the flower, the production of the male gametes (pollen grains, in the androecium) and female gametes (ovules, in the gynoecium) takes place; after pollination (transfer of the pollen from the anther to the stigma) and fertilization, seeds are formed, enclosed by the fruit. — Charles Darwin called the evolution of angiosperms and their pollinators an 'abominable mystery' because of its evolutionary speed (140 million years ago); the flower-pollinator coevolution is a classic example of mutual adaptation — flowers produce nectar as a reward, and pollinators transport pollen.

  3. Photograph, draw, or collect images of 25 types of flowers and identify them by their common name and, if possible, scientific name.

    Answer: You must assemble a collection of 25 different flowers (photographing them yourself, drawing them, or cutting them out from magazines) with the identification of each one by its common name and, if possible, scientific name. — The floral diversity requested (25 species) forces the Pathfinder to observe variations in shape (regular vs irregular), number of petals (3, 4, 5, +), colors, and environment — basic botanical knowledge; the binomial scientific name (genus + species) has been the international standard since Linnaeus (1753).

  4. Know the functions of the following parts of a flower:
    • Petal
    • Sepal
    • Androecium
    • Gynoecium

    Answer: 1) Petal: colored parts that, together, form the corolla; their function is to attract pollinators (insects, birds) through their colors and fragrance. 2) Sepal: generally green parts that, together, form the calyx; they protect the flower bud before it opens and support the flower. 3) Androecium: the male part of the flower, formed by the set of stamens; each stamen has the filament (stalk) and the anther, where the pollen grains are produced. 4) Gynoecium: the female part of the flower, formed by one or more carpels; each carpel has the ovary (where the ovules are), the style (stalk), and the stigma (the top that receives the pollen). After fertilization, the ovary turns into a fruit and the ovules into seeds. — The classic division into floral whorls — calyx (sepals), corolla (petals), androecium, gynoecium — has been described since Linnaeus (18th century); the relative position of the gynoecium (above, within, or below the other parts) classifies flowers as hypogynous, perigynous, and epigynous, an important division in botanical taxonomy.

  5. Draw and correctly classify, based on a real flower, the following parts: peduncle, receptacle, sepals, petals, calyx, corolla, androecium, gynoecium, stamen (filament and anther), carpel (ovary, stigma, style).

    Answer: You must collect a real flower (a rose, hibiscus, or tulip work well) and draw it, identifying: peduncle (the small stalk that connects the flower to the stem); receptacle (the base where the other parts attach); sepals (the outer green parts, which form the calyx); petals (the colored parts, which form the corolla). — The hibiscus (Hibiscus rosa-sinensis) is the preferred flower for this exercise because of its large size and parts clearly visible to the naked eye; roses have multiple carpels (one per inner petal), which makes the drawing more complex. The division into whorls was formalized by Linnaeus (1735) and follows the same pattern to this day.

  6. Describe the life cycle of a particular flower, including the role of insects or wind in pollination.

    Answer: Let us take the rose (Rosa sp.) as an example: the cycle begins with the bud/sprout protected by the sepals; upon receiving light and water, the bud opens, revealing the colored corolla that attracts pollinators. Insects (bees, bumblebees, butterflies) land on the flower attracted by its color and fragrance, feed on nectar/pollen, and carry pollen grains stuck to their body to another flower — depositing them on the stigma, with pollination occurring. — The flower-pollinator coevolution is one of the most elegant examples of natural selection — flowers produce nectar as a reward while pollinators transfer pollen between flowers; anemophilous species (wind-pollinated, such as grasses) dispense with showy petals and produce small, abundant pollen grains.

  7. Explain what pollination is.

    Answer: Pollination is the process of transferring pollen grains from the anthers (male part, in the androecium) to the stigma (female part, in the gynoecium) of a flower. It can be self-pollination (the pollen goes to the stigma of the same flower or of another flower of the same plant) or cross-pollination (between flowers of different plants of the same species). — Approximately 75% of the world's food crops depend on animal pollination (FAO 2016) — without bees, we would lose coffee, cocoa, apple, mango, and dozens of other foods; this is why the Conference of the Parties of the CBD (Convention on Biological Diversity) has a global program for the protection of pollinators.

  8. Do 2 of the following items:
    • Draw, collect images of, or photograph a series of at least 6 flowers, showing, in order, the colors of the rainbow: red, orange, yellow, green, blue, violet.
    • Present fresh, dried or pressed flowers that have: five petals, four petals, three petals, no petals.
    • Blindfolded, distinguish and name 2 out of 5 wild or cultivated flowers, using only the sense of smell.
    • Make a list of flowers that you observed and that were visited by different animals.
    • Observe a flower for at least 10 minutes in sunlight and for at least 10 minutes after nightfall, and report the insects that visited it. Mention the number of visitors and the name of the flower.

    Answer: You must choose and complete at least 2 of the 5 proposed items: (1) a collection of 6 flowers in the colors of the rainbow (red, orange, yellow, green, blue, violet) — green is the rarest, but it exists (Helleborus, certain orchids). — The item about observing 10 min in the sun + 10 min at night teaches the difference between diurnal pollinators (bees, butterflies, hummingbirds) and nocturnal ones (moths, bats); nocturnal flowers tend to be white and fragrant (night-blooming jasmine, jasmine) because they are easily seen in the dark and attract nocturnal pollinators.

  9. Give 1 example of flowers that are pollinated by:
    • Insects
    • Wind
    • Birds

    Answer: (1) Pollinated by insects (entomophily): rose (Rosa sp.), sunflower (Helianthus annuus), lavender (Lavandula), passionflower (Passiflora) — flowers that are typically colorful, fragrant, and with nectar, attracting bees, butterflies, and wasps. (2) Pollinated by wind (anemophily): grasses such as corn (Zea mays), wheat (Triticum), rice, pines, and oaks — discreet flowers, without showy petals, with light and abundant pollen. — Coevolution is evident: entomophilous flowers have colors visible to the insect spectrum (UV highlighted), anemophilous ones dispense with beauty and nectar (a metabolic cost) and produce abundant pollen, and ornithophilous ones have colors in the red range (visible to birds, barely perceived by insects) and a tubular shape adapted to the long beak of the hummingbird.