Sunday, August 26, 2012

Leah, Photos 20-40

(Note: I used a lot of rhododendrons in this post.  There are a lot of rhododendrons near my house and each picture is from a different individual organism.)
Anther & filament of stamen:  The stamen is the pollen-producing reproductive organ of a flower.  It is composed of the thin stalk, called the filament, and the two-lobed pollen-bearing anther on top.  There are several stamens visible in a circle within each flower.

Animal with a segmented body:  The body of an ant is divided into three distinct sections, or segments: the head, mesosoma (thorax and first abdominal segment), and the metasoma (the rest of the abdomen).

C4 plant:  C4 plants use a slightly more efficient form of carbon fixation that requires more energy, which allows them to survive better in harsh times.  This crabgrass is a C4 plant.

Cuticle layer of plant:  Plant cuticles are a protective waxy covering produced only by the epidermal cells of a plant.  It is usually thicker on top of the leaf.  The shininess of the leaf shows the thick cuticle layer on this rhododendron.

Dominant vs. recessive phenotype:  In genetics, a dominant trait will always manifest itself when paired with a recessive trait.  The four leaves on this clover are recessive compared to the much more common three-leafed clover, also seen in this picture.

Flower ovary:  The flower ovary is the part of the pistil that holds the ovules and is located around the area of the petals.  If fertilized, it later becomes the fruit.  This is a rhododendron ovary.  The rest of the pistil would have attached at the top, and the petals would have attached just below it.

Gametophytes:  A gametophyte is the single-chromosomed, multicellular phase of plants that is dominant in mosses like this one.  It also undergoes alternation of generations.  All of the small, feathery "branches" are mature haploid gametophytes.

Introduced species:  An introduced species is a nonnative species that has been brought into an area and proliferates there.  If it grows wildly enough that it is choking out native species, then it is also an invasive species.  The Himalayan Blackberry was introduced to the Americas in 1885 in an attempt to cultivate it for its large, sweet fruit.  It soon got out of control and eventually spread to the Pacific Northwest, where it is an invasive species.  It is native to Armenia.

Lichen:  A lichen is a symbiotic relationship between a fungus and a photosynthetic partner (a green alga or a cyanobacterium).  The alga or cyanobacteria provide energy for the fungus and the fungus provides water for the photosynthetic partner.  This is Parmotrema perlatum, a grey, leafy form of lichen.

Long-day plant:  Many flowering plants sense seasonal changes in night length, or photoperiod, using them as signals to flower.  Long-day plants flower when the day length exceeds their critical photoperiod, e.g. late spring or early summer.  Like most other plants, clover flowers in late spring, making it a long-day plant.

Meristem:  The meristem is the plant equivalent of stem cells, in that they are undifferentiated growing dividing cells that will give rise to multiple types of tissue.  In this picture of a tiny maple seedling, the shoot in the center is composed of meristematic tissue and will continue to grow.

Modified root:  This is a beet.  Beets, like carrots and potatoes, are/have tubers.  Tubers are roots that have been enlarged to store nutrients and help plants to survive the winter.

Modified stem:  This is a blackberry thorn, a heavily modified stem that is short and sharp.  Thorns developed to discourage predators from eating the plant.

Phloem:  Phloem carries nutrients like sugar throughout the plant where it is needed.  Unlike xylem, this tissue is still alive.  In trees, like this red cedar, it is the innermost layer of the bark.

Pollen:  Pollen is a powder produced by the stamens of seed plants that contains its microgametophytes, which produce the male gametes (sperm cells).  These flowers have tiny stamens, which in turn hold the pollen.

Pollinator:  A pollinator is the animal, usually an insect, that moves pollen from the male anthers of a flower to the female stigma to accomplish fertilization.  They normally do this inadvertently while attempting to harvest the sweet nectar.  This bee is collecting clover nectar and brushing its legs against the anthers, thus also collecting pollen.  On the next flower, it also brushes against the stigma, fertilizing it.

Sporophyte:  A sporophyte is the generation of a plant or algae that has a double set of chromosomes. For common flowering plants, the sporophyte generation makes up almost the whole life cycle (the whole green plant), except for the flowers.  The flowers of this rhododendron have already run their cycle and are barely visible.  The rest of the plant is a sporophyte.

Stigma & style of carpel:  A carpel is the female, ovule and seed producing reproductive organ in flowering plants.  The style is the stalk containing pollen tubes that connect the stigma and the ovary.  The stigma is the slightly sticky portion atop the style that collects the pollen.  The rhododendron carpel is visible on top of the penny in this picture, with the stigma visible as the black portion on the end.

Monocots vs. dicots (roots):  The grass (left) has roots that simply thread out individually, with no specific pattern, like all monocots.  The dicot maple seedling (right), however, has roots that branch off of a single taproot, or radicle.

Monocots vs. dicots (leaves): (I couldn't get this picture to focus any better.)  The piece of grass has veins that run parallel to one another along its whole length, identifying it as a monocot.  The rhododendron leaf, like all dicots, has veins that branch off of a central one, alternating sides.

Animals in different phyla:  Both the fly and the dog in this picture are motile, heterotrophs (the dog eats dog food, the fly eats liquids), and multicellular.  Thus, they are both animals.  
The fly belongs to the phylum Arthropoda, as an invertebrate animal with an exoskeleton, a segmented body, and jointed appendages.
The dog belongs to the phylum Chordata, with a spinal cord and a tail (and several features only present in development).  All mammals are Chordates, therefore this dog is one.

Plants in different divisions:  There is a red cedar in the back of this picture.  Red cedars bear small, brown cones enclosing seeds, the identifying trait of a gymnosperm.  The bush in the front of the picture is a rhododendron.  Rhododendrons, like all angiosperms, have flowers, endosperm inside the seeds, and the fruits that contain the seeds.  The dead flowers are still visible on the bush.

1 comment:

  1. "Long-day plant: Many flowering plants sense seasonal changes in night length, or photoperiod, using them as signals to flower. Long-day plants flower when the day length exceeds their critical photoperiod, e.g. late spring or early summer. Like most other plants, clover flowers in late spring, making it a long-day plant." What are some other long-day plants? How do you think they can sense seasonal changes?