mark and recapture

Examples of mark and recapture in the following topics:

• Population Size and Density

  • Scientists study population size and density using a variety of field sampling methods, including quadrats and mark-recapture.
  • Scientists typically use the mark and recapture technique for mobile organisms such as mammals, birds, or fish .
  • The mark and recapture method has limitations.
  • Mark and recapture is used to measure the population size of mobile animals.
  • With the mark and recapture method, researchers capture animals and mark them with tags, bands, paint, body markings or some other sign.

• Evolution of Land Plants

  • The geologic periods of the Paleozoic are marked by changes in the plant life that inhabited the earth.
  • The major event to mark the Ordovician, more than 500 million years ago, was the colonization of land by the ancestors of modern land plants.
  • The evolution of plants occurred by a gradual development of novel structures and reproduction mechanisms .
  • Paleobotanists collect fossil specimens in the field and place them in the context of the geological sediments and other fossilized organisms surrounding them.
  • Fossils indicate that by the end of the Devonian period, ferns, horsetails, and seed plants populated the landscape, giving rising to trees and forests.

• Post-Cambrian Evolution and Mass Extinctions

  • The periods that followed the Cambrian during the Paleozoic Era were marked by further animal evolution and the emergence of many new orders, families, and species.
  • The end of the Permian period (and the Paleozoic Era) was marked by the largest mass extinction event in Earth's history, a loss of roughly 95 percent of the extant species at that time.
  • The warm and stable climatic conditions of the ensuing Mesozoic Era promoted an explosive diversification of dinosaurs into every conceivable niche in land, air, and water.
  • Plants died, herbivores and carnivores starved, and the mostly cold-blooded dinosaurs ceded their dominance of the landscape to more warm-blooded mammals.
  • The appearance and dominance of flowering plants in the Cenozoic Era created new niches for insects, as well as for birds and mammals.

• The Cambrian Explosion of Animal Life

  • The Cambrian period, occurring between approximately 542–488 million years ago, marks the most rapid evolution of new animal phyla and animal diversity in earth's history.
  • Echinoderms, mollusks, worms, arthropods, and chordates arose during this period.
  • Yet other theories claim genetic and developmental reasons for the Cambrian explosion.
  • The answer may very well be a combination of these and other theories.
  • Despite some of these arguments, most scientists agree that the Cambrian period marked a time of impressively-rapid animal evolution and diversification that is unmatched elsewhere during history.

• Regulating Protein Activity and Longevity

  • Proteins can be chemically modified with the addition of methyl, phosphate, acetyl, and ubiquitin groups.
  • Methylation on carboxylate side chains covers up a negative charge and adds hydrophobicity.
  • The addition of this chemical group changes the property of the protein and, thus, affects it activity.
  • The addition of an ubiquitin group to a protein marks that protein for degradation.
  • Proteins with ubiquitin tags are marked for degradation within the proteasome.

• Streptophytes and Reproduction of Green Algae

  • The brown, red, and gold algae, however, have been reassigned to the Protista kingdom.
  • This is because, apart from their ability to capture light energy and fix CO2, they lack many structural and biochemical traits that distinguish plants from protists.
  • Green algae contain the same carotenoids and chlorophyll a and b as land plants, whereas other algae have different accessory pigments and types of chlorophyll molecules in addition to chlorophyll a.
  • Both green algae and land plants also store carbohydrates as starch.
  • Charophyta are a small but important group of plants which show marked differences from both the Thallophyta and the Bryophyta.

• Pre-Cambrian Animal Life

  • However, recently there has been increasing scientific evidence suggesting that more varied and complex animal species lived during this time, and possibly even before the Ediacaran period.
  • Other organisms, such as Cyclomedusa and Dickinsonia, also evolved during the Ediacaran period .
  • These fossils from South Australia date back 650 million years, actually placing the putative animal before the great ice age extinction event that marked the transition between the Cryogenian period and the Ediacaran period.
  • Fossils of (a) Cyclomedusa and (b) Dickinsonia that evolved during the Ediacaran period.
  • (a) Earth's history is divided into eons, eras, and periods.

• Introduction to the Study of Biology

  • Biology is the study of life and living things through rigorously-tested and peer-reviewed scientific research methods.
  • However, despite the broad scope of biology, there are certain general and unifying concepts that govern all study and research:
  • evolution accounts for the unity and diversity seen among living organisms
  • In 1953, the discovery of the double helical structure of DNA marked the transition to the era of molecular genetics.
  • Spurzheim's divisions of the organs of phrenology marked externally

• Antibody Functions

  • Antibodies, part of the humoral immune response, are involved in pathogen detection and neutralization.
  • Once secreted, antibodies circulate freely and act independently of plasma cells.
  • Antibodies also mark pathogens for destruction by phagocytic cells, such as macrophages or neutrophils, because they are highly attracted to macromolecules complexed with antibodies.
  • Not all antibodies bind with the same strength, specificity, and stability.
  • Conversely, antibodies raised against pathogenic molecular components that resemble self molecules may incorrectly mark host cells for destruction, causing autoimmune damage.

• Biodiversity Change through Geological Time

  • Both are natural "birth" and "death" processes of macroevolution.
  • These two extinction events, cooling and warming, were separated by about 1 million years; the climate changes affected temperatures and sea levels.
  • This hypothesis, proposed first in 1980, was a radical explanation based on a sharp spike in the levels of iridium (which rains down from space in meteors at a fairly constant rate, but is otherwise absent on earth's surface) at the rock stratum that marks the boundary between the Cretaceous and Paleogene periods .
  • The Cretaceous-Paleogene (K-Pg) boundary marked the disappearance of the dinosaurs in fossils, as well as many other taxa.
  • In 1980, Luis and Walter Alvarez, Frank Asaro, and Helen Michels discovered, across the world, a spike in the concentration of iridium within the sedimentary layer at the K–Pg boundary.