Response of green hydra (Hydra viridissima) to variability and directional changes in food availability

Biologia ◽  
2015 ◽  
Vol 70 (10) ◽  
Author(s):  
Márta E. Rosa ◽  
Flóra Bradács ◽  
Jácint Tökölyi
Keyword(s):  
Environmental Change ◽  
Stress Tolerance ◽  
Food Availability ◽  
Environmental Changes ◽  
Control Group ◽  
Delayed Response ◽  
Natural Environments ◽  
Feeding Frequency ◽  
Green Hydra ◽  
Response To Environmental Change

AbstractNatural environments tend to be variable resulting in alternating periods of high and low food availability. Therefore, animals have to be able to accommodate to sudden environmental changes by adjusting their physiology and behaviour to new conditions. We investigated how simulated food variability affects life history traits (asexual reproduction and stress tolerance) and response to environmental change in laboratory experiments with green hydra (Hydra viridissima). We assigned hydra into four groups differing in feeding frequency (high or low) and food regularity (random or stable). After 21 days of accommodation, feeding frequency was changed (increased or decreased) in half of each group, the other half was kept as a control group. Hydra showed a delayed response to environmental change (increased or decreased feeding frequency). This delay in response was greater under an unpredictable feeding scheme. Animals on a random scheme had lower budding rates and lower stress tolerance. Follow-up experiments suggest that this might be due to receiving food on subsequent days, since we found that animals fed daily have lower budding rates than those fed on alternate days. We hypothesize that frequent feeding might cause high levels of oxidative/xenobiotic stress which could overwhelm the defence system of these animals.

scholarly journals Modes of response to environmental change and the elusive empirical evidence for bet hedging

2011 ◽  
Vol 278 (1712) ◽  
pp. 1601-1609 ◽  
Author(s):  
Andrew M. Simons
Keyword(s):  
Environmental Change ◽  
Empirical Evidence ◽  
Natural Environments ◽  
Bet Hedging ◽  
Fluctuating Selection ◽  
Hedging Strategies ◽  
Evolutionary Response ◽  
Human Decision ◽  
Response To Environmental Change

Uncertainty is a problem not only in human decision-making, but is a prevalent quality of natural environments and thus requires evolutionary response. Unpredictable natural selection is expected to result in the evolution of bet-hedging strategies, which are adaptations to long-term fluctuating selection. Despite a recent surge of interest in bet hedging, its study remains mired in conceptual and practical difficulties, compounded by confusion over what constitutes evidence for its existence. Here, I attempt to resolve misunderstandings about bet hedging and its relationship with other modes of response to environmental change, identify the challenges inherent to its study and assess the state of existing empirical evidence. The variety and distribution of plausible bet-hedging traits found across 16 phyla in over 100 studies suggest their ubiquity. Thus, bet hedging should be considered a specific mode of response to environmental change. However, the distribution of bet-hedging studies across evidence categories—defined according to potential strength—is heavily skewed towards weaker categories, underscoring the need for direct appraisals of the adaptive significance of putative bet-hedging traits in nature.

scholarly journals The Effect of Learning Environmental Change Material by Problem Based Learning toward Students’ Learning Outcomes

2019 ◽  
Vol 8 (1) ◽  
pp. 8-14
Author(s):  
Devi Erfa Susani ◽  
Sri Ngabekti ◽  
Bambang Priyono
Keyword(s):  
Environmental Change ◽  
Student Learning ◽  
Learning Outcomes ◽  
Environmental Changes ◽  
Problem Based Learning ◽  
Student Learning Outcomes ◽  
Control Group ◽  
Learning Material ◽  
Environmental Care ◽  
Change Material

The results of the Biology teacher's interview at SMA Negeri 1 Petarukan shows that learning material for environmental change is carried out using varied lectures. The learning makes students less active in learning, so that student learning outcomes are low. This is indicated by the completeness of student learning outcomes in the two classes that are taught using varied lectures are 45% and 50% respectively. Learning about environmental change material that has been carried out has not linked the material to environmental care. One learning model that can be applied to improve learning outcomes and environmental care attitudes is problem based learning (PBL). This study aims to determine the effect of the application of PBL learning material on environmental changes to learning outcomes and environmental care attitudes. This research is a Quasi-Experimental Design with Nonequivalent Control Group Design. The sample in this study is class X MIPA 1 (experiment) and X MIPA 2 (control) which is taken using objective sampling technique. The results of the t-test show that t-count = 3.28 > t-table (df = 68) = 1.99 means that the learning outcomes of the experimental class on environmental change material are higher than the control class. The N-gain test results show that the experimental class obtains the N-gain category with high criteria, while the control class obtained the N-gain category with moderate criteria. The classical completeness of learning outcomes in the experimental class is 91.1% while the control class is 75%. PBL learning can also foster an attitude of caring for the students as indicated by the results of the environmental care questionnaire obtaining very good criteria. Based on the results of the study it is concluded that learning material changes in the environment of the PBL model had a significant effect on student learning outcomes in SMAN 1 Petarukan.

scholarly journals Global Phylogeographic and Admixture Patterns in Grey Wolves and Genetic Legacy of An Ancient Siberian Lineage

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Małgorzata Pilot ◽  
Andre E. Moura ◽  
Innokentiy M. Okhlopkov ◽  
Nikolay V. Mamaev ◽  
Abdulaziz N. Alagaili ◽  
...  
Keyword(s):  
Environmental Change ◽  
Environmental Changes ◽  
Phylogeographic Structure ◽  
Evolutionary Relationships ◽  
Clustering Methods ◽  
Species Response ◽  
Genome Wide ◽  
Response To Environmental Change ◽  
Ambiguous Position ◽  
Insight Into

AbstractThe evolutionary relationships between extinct and extant lineages provide important insight into species’ response to environmental change. The grey wolf is among the few Holarctic large carnivores that survived the Late Pleistocene megafaunal extinctions, responding to that period’s profound environmental changes with loss of distinct lineages and phylogeographic shifts, and undergoing domestication. We reconstructed global genome-wide phylogeographic patterns in modern wolves, including previously underrepresented Siberian wolves, and assessed their evolutionary relationships with a previously genotyped wolf from Taimyr, Siberia, dated at 35 Kya. The inferred phylogeographic structure was affected by admixture with dogs, coyotes and golden jackals, stressing the importance of accounting for this process in phylogeographic studies. The Taimyr lineage was distinct from modern Siberian wolves and constituted a sister lineage of modern Eurasian wolves and domestic dogs, with an ambiguous position relative to North American wolves. We detected gene flow from the Taimyr lineage to Arctic dog breeds, but population clustering methods indicated closer similarity of the Taimyr wolf to modern wolves than dogs, implying complex post-divergence relationships among these lineages. Our study shows that introgression from ecologically diverse con-specific and con-generic populations was common in wolves’ evolutionary history, and could have facilitated their adaptation to environmental change.

scholarly journals Remodeling of Yeast Genome Expression in Response to Environmental Changes

2001 ◽  
Vol 12 (2) ◽  
pp. 323-337 ◽  
Author(s):  
Helen C. Causton ◽  
Bing Ren ◽  
Sang Seok Koh ◽  
Christopher T. Harbison ◽  
Elenita Kanin ◽  
...  
Keyword(s):  
Environmental Change ◽  
Expression Analysis ◽  
Environmental Changes ◽  
Transcriptional Response ◽  
Yeast Genome ◽  
Temperature Oxidation ◽  
Genome Wide ◽  
Environmental Responses ◽  
Yeast Genes ◽  
Response To Environmental Change

We used genome-wide expression analysis to explore how gene expression in Saccharomyces cerevisiae is remodeled in response to various changes in extracellular environment, including changes in temperature, oxidation, nutrients, pH, and osmolarity. The results demonstrate that more than half of the genome is involved in various responses to environmental change and identify the global set of genes induced and repressed by each condition. These data implicate a substantial number of previously uncharacterized genes in these responses and reveal a signature common to environmental responses that involves ∼10% of yeast genes. The results of expression analysis with MSN2/MSN4 mutants support the model that the Msn2/Msn4 activators induce the common response to environmental change. These results provide a global description of the transcriptional response to environmental change and extend our understanding of the role of activators in effecting this response.

scholarly journals Effects of environmental change on population nutrition and health: A comprehensive framework with a focus on fruits and vegetables

2017 ◽  
Vol 2 ◽  
pp. 21 ◽  
Author(s):  
Hanna L. Tuomisto ◽  
Pauline F.D. Scheelbeek ◽  
Zaid Chalabi ◽  
Rosemary Green ◽  
Richard D. Smith ◽  
...  
Keyword(s):  
Environmental Change ◽  
Health Outcomes ◽  
Food Availability ◽  
Agricultural Production ◽  
Fruits And Vegetables ◽  
Environmental Changes ◽  
Well Being ◽  
Nutrition And Health ◽  
Crop Quality ◽  
The Impact

Environmental changes are likely to affect agricultural production over the next 20–30 years. The interactions between environmental change, agricultural yields and crop quality, and the critical pathways to future diets and health outcomes remain largely undefined. There are currently no quantitative models to test the impact of multiple environmental changes on nutrition and health outcomes. Using an interdisciplinary approach, we developed a framework to link the multiple interactions between environmental change, agricultural productivity and crop quality, population-level food availability, dietary intake and health outcomes, with a specific focus on fruits and vegetables. The main components of the framework consist of: i) socio-economic and societal factors, ii) environmental change stressors, iii) interventions and policies, iv) food system activities, v) food and nutrition security, and vi) health and well-being outcomes. The framework, based on currently available evidence, provides an overview of the multidimensional and complex interactions between environmental change, diets and health, and forms the analytical baseline for future modelling and scenario testing. The framework identifies the inter-sectoral datasets and models that need to be defined and populated to assess the impacts of environmental change on agricultural production, food availability, nutrition and population health.

USING HISTORICAL ANNUAL REPORTS IN TEACHING: LETTING THE PAST BENEFIT THE PRESENT

1992 ◽  
Vol 19 (1) ◽  
pp. 29-50 ◽  
Author(s):  
Joel Amernic ◽  
Ramy Elitzur
Keyword(s):  
Environmental Change ◽  
Cash Flow ◽  
Accounting Education ◽  
Annual Reports ◽  
The Past ◽  
Response To Environmental Change

In this article, it is suggested that accounting education may be enhanced by the use of published historical accounting materials, such as annual reports. Comparing such materials with modern reports serves to reinforce the notion that accounting evolves in response to environmental change. Further, requiring students to analytically derive cash flow statements from historical published annual reports provides several direct pedagogical benefits.

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