Follow by Email

Monday, September 19, 2016

DOES COEXISTENCE EQUAL COMPETITION?




Not necessarily and, in fact, maybe not usually, especially in the temperate zone.  In this first video in the series The Living World (which follows the AP Environmental Science curriculum), the construction of an ecological community is explored.  It begins by exploring the curious case of the Louisiana (above) and Northern waterthrushes, which despite being exceedingly similar in what they do and where they live, down to even nesting in the same upturned root of the same tree, do not exhibit any appreciable interspecific competition.  The issue is that there must be something to compete over, and in this case particularly food has been found to be in abundance. 

The video reviews the concept of the ecological niche and discusses the categories and components of the niche.  It further relates this concept to more typical pairs of species that, although related to each other, exhibit ecological differences that place them into separate niches.  It examines how species within a community can differ from one another along single and multiple resource axes. 

It also investigates how communities can change seasonally, with individual species changing their distributions and habitat use seasonally.  It concludes by exploring how communities are affected by habitat size, and discusses the species-area effect and what sorts of phenomena can lead to this effect.

As with other videos in this series, it is available through Arts and Academic Publishing- the publishing partner of Bird ConservationResearch, Inc.


Tuesday, September 6, 2016

WHY DO PLANTS HAVE COLORS?


Why do plants have colors?  Why do some plants grow in certain places and not others?  It has to do in large part with the properties of the soil that the plants grow in.  In the video Earth Systems and Resources: Soil Properties, which follows the national AP Environmental Science curriculum, these issues are investigated.  In many instances, soil micronutrients are responsible for phenomena like color and presence/ absence, but soil structure, soil particle size, slope and the interaction of plants and mineral soil can further influence these.  Hence, topics like soil horizons, soil textures and macro- vs. micronutrients, are also explored in the video. 

Soil nutrients are explored in particular detail.  For example, each nutrient is responsible for certain functions, with elements like iron being involved in the functioning of the electron transport system and calcium being involved in the permeability of the cell membrane.  Moreover, various soil types have differing capacities to exchange nutrients with plants.  Coarser soils tend to have poorer abilities to hold and exchange nutrients than do soils with clays as components.

The video also explores the issue of soil water.  Again, soils of different textures have varying abilities to retain water, with soil pore size influencing this capacity.


As with other videos in this series, it is available through Arts and Academic Publishing- the publishing partner of Bird ConservationResearch, Inc.