More deaths than poachers, deforestation or pollution. An estimated 1.3 million animals die every day after being struck by cars and trucks in Brazil, according to a recent study by Centro Brasileiro de Estudos em Ecologia de Estradas. That's 475 million animals every year in one country alone: about 15 animals every second. Over the duration of the study, the team documented the deaths of 165 different species: 10 amphibian, 21 reptile, 63 avian and 71 mammal.
Double fertilization in Arabidopsis. Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower.
Pollen in Angiosperms. In angiosperms, pollen is produced by the anther, which sits on the filament in the center of the flower. Look closely and you will most certainly see the fine yellow powder on each anther.In order to complete fertilization, pollen must make its way to another plant.ollen grains are microscopic structures that carry the male reproductive cell of plants. The inside of the grain contains cytoplasm along with the tube cell (which becomes the pollen tube) and the generative cell (which releases the sperm nuclei).