BIOLOGY

BIOLOGY



BIOLOGY

Natural selection

A lizard called the flat-tailed horned lizard lives in the American Southwest. The most distinctive feature of these small lizards is the fringe of horns that goes from one side of the skull around the back to the other side of the skull (see the photo).

The main predator of this lizard is a bird that kills it by biting through the spine at the back of the skull. Researchers studying this lizard observed that the lizards defend themselves against this attack by throwing their head backward and stabbing at the attacker with their horns. The researchers wondered if having longer back horns and a wider spread of side horns (from tip on right side to the tip on the left side) was advantageous for the lizards. They collected data on the length of the back horns and the total width of the side horns on live lizards and killed lizards. The researchers measured 155 live animals and 29 killed animals.

Average horn

length (mm)

Rear horns

Killed

8.5

Live

10

Side horns

Killed

20

Live

24

Using the appropriate format, graph the above data. Place all the data (for both sets of horn measurements) on the same graph.

The flat-tailed horned lizard has the most restricted range of any species of horned lizard in the United States (Stebbins 2003). The FTHL range is limited to southeastern California and southwestern Arizona, but also covers areas of Sonora and Baja California Norte, Mexico. Much historical FTHL habitat has been converted to agriculture, urban areas, or covered suggested that 50% of the FTHL's current range in California, Arizona and Baja California was at risk due to additional habitat conversion. This remaining habitat is being impacted by mining, geothermal development, immigration, border patrols, power lines, roads and off-highway vehicle traffic. Due in part to these factors the FTHL was proposed in 1993 for listing under the federal Endangered Species Act (U.S. Fish and Wildlife Service 1993). The proposal for federal protection was withdrawn in 1997 due to insufficient evidence to justify listing (U.S. Fish and Wildlife Service 1997). In response to litigation, a court ordered the Secretary of the Interior and the U. S. Fish and Wildlife Service to reconsider the lizard for listing again in 2001, but this proposal was withdrawn in 2003 (U.S. Fish and Wildlife Service 2003). Again in response to litigation, a judge ruled in August 2005 that the U.S. Fish and Wildlife Service violated the Endangered Species Act during its latest consideration of the FTHL for listing. The need for reliable estimates of the distribution and abundance of the FTHL, as well as identifying factors that affect these parameters, is evident.

Plant Reproduction

Moreover, the fruit and vegetables are totally different from each other as they have separate genetics which would later on help them develop their sexes whether they are male or female. Fruits and vegetables are different from each other such that they are fruits grow from ovum which is in seeds and they reproduce by bearing seeds and vegetables are basically the edible part of a ...