Current research indicates that mammals did not explosively diversify across the K Pg boundary, despite the environment niches made available by the extinction of dinosaurs.
However, the various P. aeruginosa strains originating from different environment niches differ in accessory genome regions, genome expression profiles, virulence activities and antibiotic resistances.
Depending on the cell type MSC develop in certain environment niches with a low oxygen tension varying between 1% and 7% O2 in BM and between 10% and 15% O2 in adipose tissue (AT) [ 8- 10].
Just as biological organisms are shaped by ecological niches, language structures appear to adapt to the environment (niche) in which they are being learned and used.
δ e =0.0 means that P. ridibundus have the same fitness as P. lessonae (i.e. the environment includes niches for both species), while δ e =0.4 represents the fact that P. ridibundus are strongly disadvantaged compared to P. lessonae (i.e. the environment consists of a typical P. lessonae habitat).
The driving force behind ecological speciation is thus divergent natural selection between environments or, in other words, reproductive isolation of populations by means of adaptation to different environments or niches [ 18, 19, 21, 27, 28].
In her project, Sipkins will investigate molecular characteristics of tissue micro-environments, or "niches," within the bone marrow and how normal, healthy hematopoietic stem cells, which give rise to the many kinds of blood cells, compete with malignant cells to occupy these coveted niches.
Comparison and classification of metagenome samples is one of the major tasks in the study of microbial communities of natural environments or niches on human bodies.
The speciation process is thought to involve an initial period of resource polymorphism, during which the parent lineage utilizes multiple environments or niches [ 3, 4]; subsequently, tradeoffs in the efficiency by which individuals can use different resources lead to disruptive selection and, eventually, to lineage splitting [ 5, 6].
It has been argued that acquisition of specific elements, especially IS 16, has contributed to the ecological success of hospital-associated E. faecium strains allowing higher levels of genetic variability including easier acquisition of mobile genetic elements that may support lifestyle in new or changing environments or ecological niches like the hospital environment [ 3, 44].
Adult Albertosaurs were the apex predators in this environment, with intermediate niches possibly filled by juvenile albertosaurs.
