Sentences with phrase «populations change over time»

«This is a relatively common way that insect populations change over time.

Yet, scientists know very little about how our resident bacteria come to live with us, or how these populations change over time.

Mass Audubon scientists, mapping experts, and IT specialists are currently analyzing the first five years of data so that they can be used to track population changes over time.

From their experiments, the researchers developed a simple model to predict the type of mutualistic relationship that would develop between the two strains, given how their populations changed over time.

For example, when a population changes over time, can we use statistics to determine whether chance or selection drives those changes?

In reality, most TNR programs are volunteer - based, understaffed, and can not sterilize all cats in a colony or monitor colony health or population changes over time (Jessup 2004).

Activist polar explorer Børge Ousland's told National Geographic that more polar bear encounters on land are due to reduced sea ice — without any reference to population changes over that time or revealing when or where these observations were made.

Not exact matches

Biologists define evolution as a change in the gene pool of a population over time.

One can of course not hide the fact that in the United States, too, the Christian heritage is decaying at an incessant pace, while at the same time the rapid increase in the Hispanic population and the presence of religious traditions from all over the world have changed the picture.

Evolution the fact is defined as a change in allele frequency in a population over time.

All the theory of evolution says is that life forms adapt to changes in the environment over time; that there are global changes in the gene pool of a given population of animals over time.

A common way to use the term evolution is simply to describe the change in the gene pool of a population over time; that this occurs is an indisputable fact.

But over time its population increased, its class divisions became more pronounced, its ethnic composition became more diverse, its neighborhoods changed their configurations, and its economic system became more geared to the impersonality of the marketplace.

The notion that purely random mutation preserved in the population by natural selection would produce a gradual change, which over time would create the complexity of life we now observe (phyletic gradualism).

Over time, these changes are likely to influence population nutrient intakes and reduce CVD risk factors.

The resulting data is used to compare relative abundance of seabirds over time — to help us understand populations within the sanctuary and their possible impacts on local ecosystems and as a barometer for other changes in the environment.

A kind of re-examination is scheduled every four years, to accommodate the fact that the mental state of the president or that of the average population might change over time.

Its less than a generation and Andy's calculation suggests that over half the population of this constituency has changed during that time.

Lotze says, «It would be interesting to have more surveys being repeated over time, to gain insight into changing perceptions within a population over time.

What has been called the modern synthesis of the two fields emerged in the 1940s with the idea that the sorts of genetic differences you could observe in populations, right out your window, when compounded and extrapolated over vast periods of time, could account for the large - scale changes we see in the fossil record.

Some experiments were considered quirky by 19th century standards, but the work provided data supporting Darwin's notions about trait variability in a population and how natural selection drives changes in populations over time.

«These aren't changes you can see out in the field; we're looking for trends over time in the whole population.»

To estimate changes in the size of the orangutan population over time, Voigt, along with Serge Wich from Liverpool John Moores University in the UK and their colleagues representing 38 international institutions, compiled field surveys conducted from 1999 to 2015.

The consequences of such initiative were disastrous: Protected from hunting for 35 years, and devoid of natural predators, the beavers grew over 5,000 times their initial population, caused irreversible changes in the forest ecosystem, and started advancing over the continent.

«If you look at any individual species, you can see what its population has been doing over time based on how many changes they have in their genome.

When combined with other surveys such as the Breeding Bird Survey, it provides a picture of how the continent's bird populations have changed in time and space over the past hundred years.

With the advent of more and more sophisticated ways to measure genetic variation and relatedness using molecular markers, such as allozyme polymorphisms and DNA - based markers, not only can individuals be tracked as to their parentage, but changes in allele patterns over time and thus the effects of evolution on populations can be «seen» in the genetic information.

The team hopes the new information helps conservationists working to save the great white shark from the jaws of extinction predict how the species» population will change over time.

Today, evolution is defined as the change in the frequency of alleles in populations over time.

The camera trapping tells a lot about populations — like, the numbers at any point in time, densities, how those numbers are changing over time.

«Advances in genetic sequencing technologies now allow us to find patterns in large, diverse populations of microorganisms, see how they associate with specific individuals, and understand how they change over time in a way we couldn't just a few years ago,» said Knight, who leads the UC San Diego Microbiome and Microbial Sciences Initiative.

Simulations of how the DNA changed over time suggest that polar bear populations rose and fell with the temperature.

Simulation Server allows students to model genetic changes over time — simulating the same conditions in 100 or more test populations at a time.

Dr. Beth Shapiro, whose work focuses on how populations of organisms respond to climate and habitat change over time, has isolated ancient DNA from a variety of Pleistocene and Holocene species.

Average long - term weight gain in nonobese populations is gradual — in the cohorts we studied, about 0.8 lb per year — but accumulated over time, even modest increases in weight have implications for long - term adiposity - related metabolic dysfunction, diabetes, cardiovascular disease, and cancer.21 - 24 Whereas weight changes associated with any single lifestyle factor were relatively modest in our three cohorts, in the aggregate, changes in diet and physical activity accounted for large differences in weight gain.

It is understood that many mobs still can not digest the idea that was interracial dating, but the majority of the population has changed its position over time and achieve the level of service that opens the key to success in all areas of life.

Over at The New York Times, a groovy interactive 2010 U.S. Census map that allows you to browse population growth and decline, changes in racial and ethnic concentrations, and patterns of housing development

At a time when women make up 50.8 % of the U.S. population, just 4.2 % of the 100 top - grossing American films are made by female directors; and that statistic hasn't changed over the last decade.

A dissimilarity index at the district level, however, measures the dissimilarity of districts and the overall student population in the area, and provides information on changes over time in racial differences in the distribution of students among districts.

Interact with the charts below to see how graduation rates for U.S. students, and different student populations, have changed over time and how your state's graduation rate compares.

We also include student fixed effects, which account for changes in the composition of the schools» student populations over time that can not be explained by the limited set of student characteristics for which information was available in the district's database.

The authors examined not only changes in the grade distribution over time but also changes in the educational system and in the characteristics of the student populations.

For the other variables, each percent increase in the poverty rate would mean an increase of 0.35 percentage points in the boundary participation rate, each percent increase in the change of African American population over time would mean an increase of 0.75 percentage points in the boundary participation rate, and each percent increase in the share of the population that is African American would mean a decrease of 0.29 percentage points in the boundary participation rate.

Over this time, however, significant changes have occurred in the demography of the U.S. student population, in the technology available for research, and in the data available beyond the national surveys.

Students then explore how the color of the rabbit population changes as the environment changes over time.

The tables below show how the ownership population of each device has changed over time — the most recent data come from our surveys in January.

Over the past ten years, we have seen significant changes in the pet population at our shelter — changes that require more sophisticated responses to their needs, along with a greater investment of time and resources to rehabilitate pets so they can find new, loving homes.

There was the geological evidence showing that the Earth was at least millions of years old; the evidence for extinction, and for wholesale changes in the biota over time; the work on biological classification which had advanced greatly since Linnaeus (it wasn't Darwin who recognised that «Darwin's finches» were all finches); work on the distribution of organisms across the earth; speculations about evolution going back to Lamarck, and Darwin's own grandfather Erasmus; Malthus» work on the implications of the tendency of populations to increase geometrically and hence the pressure on resources.

The problem is we have a dangerous climate change problem over 50 year approx time frame of Paris accord and its hard to see how we could get population small enough fast enough to make much difference.

In the course of reading the book you learn a great deal about how population and consumption have changed over time.