Exploring Animal Photoreceptors and Eyes: Tested Studies for Laboratory Teaching

In this exercise, students examine an array of invertebrates and vertebrates to explore structure-function relationships among animals, using photoreception and vision as a context. This exercise was developed to accompany aPhysics-based lab (Barney et al. 2009), in which students model the physical relationships of different structural “eye” types. Building on the biodiversity component, students examine simple eyespots (Dugesia); a variety of eyes that use “pinholes” to channel light rays; and the eyes of scallops (Pecten) which include reflective “mirror” surfaces. Students also study microscope slides to examine structure-function relationships in insect compound eyes and to compare the retinas of various vertebrates. Additionally, they dissect a representative mammalian eye (Bos). In an optional investigation, students collect data from humans to test a working hypothesis about the relationship between age and accommodation

Authentic Assessment Using Biology Lab Practicals

Authentic assessment tasks use real world contexts and are aligned with the assessment and content standards we create (Doran et al., 1998). In the context of gathering data to better understand the strengths and weaknesses of student learning (Angelo and Cross, 1993), the assessment cycle that the instructor employs becomes directly analogous to the process that scientists themselves employ in scientific research (D’Avanzo, 2000). Biology laboratory practicals present a great opportunity to authentically assess individual student achievement of laboratory and field skills and, where multiple lab sections characterize the institution, lend themselves well to the collection and analysis of data on student learning. Yet, lab practicals seem to have become less common over the past few decades while science education reform, and most of our colleges and universities, have indicated an increasing need for documenting our assessment strategies over the same time period

Fruit Laxatives and Seed Passage Rates in Frugivores: Consequences for Plant Reproductive Success

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/119059/1/ecy1994754989.pd

Transient And Asymptotic Dynamics Of Pioneer Plant Populations In A Costa Rican Cloud Forest

Pioneer plants depend upon canopy disturbance for recruitment, and years with high disturbance rates generate pulses of recruitment that might result in highly skewed stage or age distributions that persist for many years. We investigated this potential in five common species of pioneers at Monteverde, Costa Rica with demographic models based on 29 years of forest disturbance data and 19 years of plant demography data. Two species (Phytolacca rivinoides and Bocconia frutescens) are short-lived as adults but have persistent soil seed banks, while two others (Cecropia polyphlebia and Urera elata) are relatively long-lived and have transient seed banks. Guettarda poasana is long-lived as an adult and has persistent seeds. Annual canopy disturbance rates varied from \u3c0.5% to 8.7%, and averaged 1.6% from 1983 to 2012. Recruitment of pioneer seedlings of all five species was up to 300% greater than the long-term average following heavy disturbance years, but for most species these large cohorts were not projected to persist into reproductive stage classes due to high mortality in rapidly-regenerating gaps. Short-lived pioneers may be exceptions to this pattern, since they mature before most gaps regenerate. Survival of seeds in the soil is a key feature of the life history of all five species (\u3e 99.9% of each population consists of dormant seeds), yet elasticity analyses showed that seed survival is the most important stage transition for only three of the five specie

Effects of Urbanization on the Population Structure of Freshwater Turtles across the United States

Landscape‐scale alterations that accompany urbanization may negatively affect the population structure of wildlife species such as freshwater turtles. Changes to nesting sites and higher mortality rates due to vehicular collisions and increased predator populations may particularly affect immature turtles and mature female turtles. We hypothesized that the proportions of adult female and immature turtles in a population will negatively correlate with landscape urbanization. As a collaborative effort of the Ecological Research as Education Network (EREN), we sampled freshwater turtle populations in 11 states across the central and eastern United States. Contrary to expectations, we found a significant positive relationship between proportions of mature female painted turtles (Chrysemys picta) and urbanization. We did not detect a relationship between urbanization and proportions of immature turtles. Urbanization may alter the thermal environment of nesting sites such that more females are produced as urbanization increases. Our approach of creating a collaborative network of scientists and students at undergraduate institutions proved valuable in terms of testing our hypothesis over a large spatial scale while also allowing students to gain hands‐on experience in conservation science

Continent-wide analysis of how urbanization affects bird-window collision mortality in North America

Characteristics of buildings and land cover surrounding buildings influence the number of bird-window collisions, yet little is known about whether bird-window collisions are associated with urbanization at large spatial scales. We initiated a continent-wide study in North America to assess how bird-window collision mortality is influenced by building characteristics, landscaping around buildings, and regional urbanization. In autumn 2014, researchers at 40 sites (N = 281 buildings) used standardized protocols to document collision mortality of birds, evaluate building characteristics, and measure local land cover and regional urbanization. Overall, 324 bird carcasses were observed (range = 0–34 per site) representing 71 species. Consistent with previous studies, we found that building size had a strong positive effect on bird-window collision mortality, but the strength of the effect on mortality depended on regional urbanization. The positive relationship between collision mortality and building size was greatest at large buildings in regions of low urbanization, locally extensive lawns, and low-density structures. Collision mortality was consistently low for small buildings, regardless of large-scale urbanization. The mechanisms shaping broad-scale variation in collision mortality during seasonal migration may be related to habitat selection at a hierarchy of scales and behavioral divergence between urban and rural bird populations. These results suggest that collision prevention measures should be prioritized at large buildings in regions of low urbanization throughout North America