Web Results

Multicellular organism - Wikipedia


Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms. .... In other groups, generally parasites, a reduction of multicellularity occurred, ....

Why do multicellular organisms generally live longer then unicellular ...


A multicellular organism usually lives longer than a one-celled organism; one- celled organism is limited to the life span of a multicellular organism, however, ...

BBC - GCSE Bitesize: Unicellular vs multicellular


This page has been archived and is no longer updated. ... Simple organisms may be unicellular, consisting of just one cell, while more ... There are advantages to being multicellular rather than unicellular. ... Back to Living and growing index ... your browser software or enabling style sheets (CSS) if you are able to do so.

Death and Dying: According to the theory of evolution, why do we die?


It's not that living things die; it's that multicellular organisms die. But why? Every single-celled ... Aging longer is just not something evolution has had a reason to optimize. ... cell division, one child cell may be slightly "younger" (less prone to death) than the other. .... The disease usually starts to affect ...

How Single-Cell Organisms Evolve Into Multicellular Ones


Feb 20, 2009 ... Right now on earth there are primitive multicellular organisms that, in many ... 1) ~223 million years ago, a species of single-celled green algae began ..... You do not see a single living organism composed of numerous cells. ... The reproductive cells are usually confined to one end of the colony, where they ...

Telomerase activity coevolves with body mass, not lifespan - NCBI


Dec 14, 2006 ... In multicellular organisms, telomerase is required to maintain telomere ... a greater risk of cancer than long lifespan, and large animals evolve repression of ... (2–5%) do not experience replicative senescence (Parrinello et al., 2003). ... Longer-lived organisms experience more cell divisions and thus a ...

Peto's Paradox and the Evolution of Cancer Suppression


Jan 1, 2014 ... In order to successfully build and maintain a multicellular body, somatic cells must ... suppressed cancer in large, long-lived organisms in the hopes of .... many of whom I do not have room to list specifically here, that ...... and mice are small animals, the former live significantly longer than the latter (28 years.

protist | biology | Britannica.com


Aug 20, 2015 ... Alternative Titles: Protista, Protoctista, unicellular organism ... the entire biotic world was generally considered divisible into just two great ... and their colleagues formally proposed the division of all living things into two ... such that many scientists no longer consider kingdom Protista to be a valid grouping...

cell - Cell division and growth | biology | Britannica.com


Aug 8, 2016 ... In unicellular organisms, cell division is the means of reproduction; ... In adults most cell division is involved in tissue renewal rather than growth, many ... this case, the mature differentiated cells do not divide, but their population is .... time in the cell division cycle, usually close to the start of DNA replic...



Darwinian Evolution | The Diversity of Life | Characteristics of Living things | Levels of ... solve problems, and have some idea about what science can and cannoit do. ... The cell theory states that all organisms are composed of one or more cells, .... classification system, adopting (generally) five kingdoms of living organisms.

More Info

Unicellular and Multicellular Organisms | Biology@TutorVista.com


The structural and functional units of all living organisms are cells. ... Nutrition is usually by the process of phagocytosis, where the food particle is engulfed ... Organisms that consist of more than one cell are known as multicellular organisms. ... Unicellular prokaryotic organisms - they are unicellular in nature and they do not...

Diffusion and the Problem of Size


Jun 18, 2004 ... All organisms need to exchange substances such as food, waste, gases and heat with their surroundings. ... As organisms get bigger their volume and surface area both get bigger, ... So how do organisms larger than 100 mm exists? ... Multicellular organisms have another difference from unicellular ones: ...

Microbes Are Immortal, So Why Aren't Humans? - Washington Post


The human body, like all multicelled organisms, grows up and then starts ... Still, the question remained: Do we age and die because our bodies are built to die, our ... what made any multicellular organism die -- was that the organism's cells had ... as brain cells, muscle cells, heart cells and so on, that no longer could divide.