Warm-up Critical thinking journaling question #1: Illustrate what a plant looks like when it has adequate water and sunlight. Illustrate what a plant looks like when it does not have adequate water and sunlight. Describe what happens to the cells that causes the different appearance in the organism.

Learning Target: I can dissect the reproductive organs of a plant to be able to describe how plant reproduction occurs I can demonstrate this by creating a diagram of the structures of a flower with labels and abbreviated functions.

Multicellular eukaryotes Photosynthetic autotrophs with green pigments chlorophyll α and β Cell wall made of cellulose Nonmotile or sessile (do not move)

Evolved 450 million years ago, and are closely related to green algae (protist).

Reproduction Alternation of Generations – life cycle in which a diploid sporophyte generation alternates with a haploid gametophyte generation

Gametophyte – haploid gamete (sex cell) that reproduces by fertilization through pollination (pollen and ovule)  hidden deep within tissues of the sporophyte plant 1.gymnosperms – found in cones 2.angiosperms – found inside flowers

Life Cycle of Gymnosperms (Ex: Pine trees)  diploid sporophytes  reproduction takes place in cones 1.pollen cones (male) – produce pollen grains 2.seed cones (female) – produce female gametophytes a. much larger than pollen cones b. base of each scale contains two ovules (eggs)

 pollination 1.takes about 2 years to complete life cycle 2.begins in the spring 3.pollen is carried by wind 4.sticky material (pollination drop) ensures that pollen grains will stay on the female cone 5. when pollen lands near ovule (egg), grain splits open and begins to grow a pollen tube which contains 2 sperm nuclei (one disintegrates, other fertilizes)

 flowers – seed bearing structures of Angiosperms

reproductive structure of an angiosperm composed of 4 specialized parts: sepals, petals, stamens, and carpals Structure of a Flower

 Sepal – leaf-like, usually green, encloses the flower bud, at the bottom of a flower  Petals – leaf-like, found just inside the sepal, brightly colored to attract insects and other pollinators  Stamens – male reproductive parts (produce pollen)  Carpels (Pistil) – female reproductive structure

Stamen(male)  Anther – oval sac which produces pollen (sperm)  Filament – long, thin stalk that supports the anther  Pollen – male sex cell of plant

Carpels/Pistil (female) Stigma – sticky top that collects pollen grains Style – narrow stalk that connects the top to the base Ovary – base that contains the ovules (eggs) Ovules – female sex cell of a flower

Life Cycle of Angiosperms  Reproduction takes place within the flower  Following pollination seeds develop inside protective structures

POLLINATION AND FERTILIZATION Pollination is the transfer of pollen from an anther to the stigma  Self - pollination is when pollen fertilizes an egg cell on the same flower (how most plants normally reproduce)  Cross - pollination is when the pollen from the flower on one plant fertilizes the egg cells of a flower on another plant (2 plants as parents)

Anemphilous - wind pollination  rely on favorable weather and sheer numbers to get pollen from one plant to another  less efficient

 bright colors and sweet nectar attract insects, birds or bats to spread pollen grains from plant to plant  more efficient  Entomophilous - animal pollination

Fruit and Seed Development As angiosperm seeds mature, ovary walls thicken to form a fruit that encloses the developing seeds  Seeds – reproductive structure found in a protective tissue (ovary)  Endosperm – food rich tissue that nourishes the seedling as it grows  Fruit – structure that contains the seeds

Animal Dispersion  Seeds are covered with a tough coating that protects them from digestive chemicals, enabling them to pass through animals unharmed  Seeds are contained in fleshy, nutritious fruits

Wind Dispersion Seeds are typically light weight, allowing them to be carried in the air or to float on the surface of water (ex: maple trees, coconuts)

Seed Dormancy Dormancy – period of time in which an embryo is alive but not growing Length of time varies depending on environmental conditions (i.e. temperature or moisture levels) Allow for long-distance dispersal Allow seeds to grow under ideal environmental conditions (ex: in the spring)

Seed Germination Germination – early growth stage of the plant embryo  Seeds absorb water, causing the food storage tissue to swell, cracking open the seed coat, and the young root emerges and begins to grow  In monocots – the single cotyledon remains underground  In dicots – the cotyledons emerge above ground, protecting the stem and first foliage leaves

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