AP Biology Summer Assignment: Photo Blog

  (Term #15: Bilateral Symmetry) Definition: Organisms that have bilateral symmetry can be divided into reflected halves along only one plane; the organism's left side is a mirror copy of its right side. Explanation: This (dead) earwig demonstrates bilateral symmetry. If you drew a line down the middle, the left and right sides would be mirror copies of each other: for example, both sides would have an antenna, half of the forceps, and three legs.

  (Term #75: Pollen) Definition: Pollen produces flowers' male gametes, which are spread by wind, water, and pollinators to other or the same flower(s) to fertilize their eggs. Explanation: Pollen is clearly visible on the anthers of this daylily flower. Pollen comes in various colors; this flower's pollen is yellow.

  (Term #88: Succession) Definition: Ecological succession refers to changes in ecosystems over time. Primary succession is building an ecosystem "from scratch" in a new location; secondary succession is the development of an ecosystem in a location where there previously was life after a disaster or major change in the habitat. Explanation: This photograph shows primary s uccession on sand (psammosere). Plants slowly spread from existing populations onto newly exposed sand.

(Term #74: Phloem) Definition: Phloem is a tissue in the inner bark of trees used to transport sugars from photosynthesis in the leaves around the plant. Dead phloem becomes part of the outer bark. Explanation: This cut branch of a tree clearly shows fractured bark (dead phloem) and the gap between the inner wood and bark.

(Term #94: Xylem) Definition: The tissue that transports water and minerals from the roots around a plant is xylem. Dead xylem is wood. Explanation: The center of the tree stump shown in the picture is wood -- dead xylem. The uneven cut shows the vertical structure of the xylem tissue.

  (Term #87: Stigma and Style of Carpel) Definition: The carpel is the female flower organ. The style is a tubelike structure that connects the flower's ovary with the stigma. The stigma at the tip of the carpel receives pollen, which moves down the style to fertilize eggs in the ovary. Explanation: The longest structure in the center of this daylily flower is the carpel. The stigma is a slightly lighter yellow/white compared to the style, which leads to the flower's ovary in the center.