The final stadial of the last glacial - Younger Dryas (12 650 - 11 500 cal yr BP) is relatively well described in sediments of European lakes, however research related to its progress in Central European area is missing. The goal of this thesis was to examine progress of this stadial based on sediment core from Černé Lake at Šumava (Czech Republic). To reconstruct climatic conditions, sub-fossil remains of Chironomidae was used. The air July temperature was estimated using Swiss-Norwegian model. Geochemical analysis was performed to determine intensity of erosion, trophic status of the lake, and sources of its organic matter. To complete information about catchment, pollen analysis was performed. Following climatic events were identified in the sediment: Older Dryas (13 583 - 13 394 cal yr BP), Alleröd (13 394 - 12 383 cal yr BP), Younger Dryas (12 383 - 11 394 cal yr BP) a Early Holocene (11 394 - 11 138 cal yr BP). Presence of two phases of Younger Dryas was not significantly proven, nevertheless, the isotope composition suggests, that the first half of this oscillation was drier. Reconstructed temperature ranged between 8,30 and 10,31řC. The mean temperature for Older Dryas event was 8,92 řC, for Alleröd 9,61 řC, Younger Dryas 9,17 řC and Early Holocene 10,00 řC. Reconstructed temperature...

During the last deglaciation, Greenland ice core records exhibit multiple, high frequency climate events including the Oldest Dryas, Bølling-Allerød and Younger Dryas, which may be linked to meltwater routing of the Laurentide Ice Sheet (LIS). Previous studies show episodic meltwater input, via the Mississippi River to the Gulf of Mexico (GOM) several thousand years before the onset of the Younger Dryas until ~13.0 kcal (thousand calendar) yrs, when meltwater may have switched to an eastern spillway, reducing thermohaline circulation (THC). Data from laminated Orca Basin in the GOM, constrained by 34 Accelerator Mass Spectrometry (AMS) 14C dates, provide the necessary resolution to assess GOM sea-surface temperature (SST) history and test the meltwater routing hypothesis. Paired Mg/Ca and δ18O data on the Foraminifera species Globigerinoides ruber (pink and white varieties) document the timing of meltwater input and temperature change with decadal resolution. White G. ruber SST results show an early 5°C increase at 17.6-16.0 kcal yrs and several SST decreases, including at 16.0-14.7 kcal yrs during the Oldest Dryas (2°C) and at 12.9-11.7 kcal yrs during the Younger Dryas (2.5°C). While the early deglaciation shows strong similarities to records from Antarctica and Tobago Basin, the late deglaciation displays climate events that coincide with Greenland and Cariaco Basin records, suggesting that GOM SST is linked to both northern and southern hemisphere climate. Isolation of the ice-volume corrected δ18O composition of seawater (δ18OGOM) shows multiple episodes of meltwater at ~16.4-15.7 kcal yrs and ~15.2-13.1 kcal yrs with white G. ruber δ18OGOM values as low as -2.5%0. The raw radiocarbon age of the cessation of meltwater in the GOM (11.375±0.40 14C kcal yrs) is synchronous with large changes in tropical surface water Δ14C, a proxy for THC strength. An early meltwater episode beginning at 16.4 kcal yrs during the Oldest Dryas supports the suggestion of enhanced seasonality in the northern North Atlantic during Greenland stadials. We suggest a corollary to the seasonality hypothesis that in addition to extreme winters during stadials, warm summers allowed for LIS melting, which may have enhanced THC slowdown.

5 ABSTRACT Long-term paleoenvironmental reconstructions provides essential interpretation of environmental changes. Multiproxy analysis of lake sediments can be used for tracking the historical evolution of lakes and significant processes which formed them over time. Subfossil Cladocera play a key ecological role in freshwater ecosystems. Sedimentary cladoceran assemblages reflect environmental changes and exhibit great potential in past environmental reconstructions. The purpose of this diploma thesis is to identify climatic changes of the time interval between the Late Glacial and the early Holocene in Černé Lake. Based on the analysis of geochemical and biological proxies, determined climatic conditions of Younger Dryas (YD). The YD oscillation in Central Europe has only been briefly described. The Czech Republic is positioned between oceanic and continental climate. The results of the multiproxy analyses suggests that climate conditions of the region during YD were similar to Western Europe with moderate wet climate conditions during the first half and drier conditions during the second half of the period. In the middle of YD there was an interesting event. Observed, probably due to high precipitation and floods. These results are based on P/L ratio, geochemical proxies, pollen analyses and record of...

This masters thesis investigates the environmental/climatic change that is thought to have brought about the economic shift and transition from Palaeolithic economic system of hunting gathering to Neolithic economic system of agriculture and domestication period around 11.000-10.000 years ago. This study uses the collected animal and plant data of the Natufian culture in the Levant region from the previous zooarchaeological and archaeobotanical literature anlyses. It shows a significant mathematical difference in the zooarchaeological assemblage measures between the Early and Late Natufian sites by calculating Economic value parameters of the Early and the Late Natufian sites, a comparison analysis was made in terms of percentage frequencies of animals site by site and between early-late periods. The result shows a significant animal food supply decrease and change-shift shown during the Younger Dryas climatic crisis times of the whole Late Natufian period sites total and early to late site by site individually, compared to whole Early Natufian period sites. It shows there is a possibility that some big-base camp Late Natufian occupation sites were better able to create coping mechanisms against food crisis/food shortage and more successfully than other Late Natufian sites during the climatic food crisis period. It shows supporting with the animal-plant data and changes in the human bones, burial practices, human teeth, diet changes and anthropological studies evidence, a big social-economic-cultural change and a huge food crisis was highly possible and humans highly possibly lived an economic crisis and an highly connected-related social-cultural crisis during the Younger Dryas in the Late Natufian times human societies.

Dryas iulia pertence à subfamília HeliconitIae e é uma borboleta que prefere voar ao sol, sendo comumente encontrada em clareiras, bordas de florestas e matas secundárias. Ovoposita em espécies de Passifloraceae preferindo, em Porto Alegre e arredores Passiflora suberosa e P. misera (PÉRICO & ARAÚJO, 1991). É abundante durante quase todo o ano, excetuando-se os meses frios de inverno, quando suas populações virtualmente se extinguem. Geralmente o maior tamanho populacional é registrado nos meses de abril e maio. Do ponto de vista genético, Dryas iulia apresenta populações grandes e uniformes; em termos de estrutura genética elas se mostram compatíveis com o modelo do isolamento pela distância. Estudos realizados por HAAG (1992), HAAG e cols., (1993) mostraram que os valores de FSTnão diferiam de zero para várias amostras ("populações") do Rio Grande do Sul. O componente devido ao endocruzamento (FIs) também não diferiu de zero, embora seu valor numérico fosse mais elevado do que o esperado. No presente estudo investigou-se amostras seqüenciais (equivalentes a quatro gerações sucessivas) da região de Águas Belas, município de Viamão, RS, quanto a polimorfismos enzimáticos e variação morfológica. Originariamente os critérios para escolha deste local, foram a detcção, em trabalhos anteriores, por HAAG (1992), HAAG e cols., (1993), de uma situação altamente sugestiva de associação não aleatória entre dois locos enzimáticos (EST e LAP) nesta população, além das medidas lineares realizadas.nas asas anteriores mostrarem que os indivíduos dessa população são em média maiores quando comparados com os de outras. As amostragens ocorreram em maio de 1992, junho de 1992, março de 1993 e maio de 1993, (I, 11,111e IV amostras respectivamente). Baseado nos dados de polimorfismo enzimático para os locos Mdhl, Mdh2, Pgml, Pgm2, Aatl, Aat2, Estl, Est2 e a-Gpdh, a população local de D. iulia de Águas Belas apresentou, nas quatro amostras, os respectivos valores de heterozigosidade média por loco por indivíduo (Ho): 0,076 Gunho/92), 0,097 (maio/92), 0,103 (março/92) e 0,122 (maio/92). O menor valor para este parâmetro ocorreu no inverno, provavelmente por perda de alelos raros devido ao acaso. A proporção de locos polimórficos (P) variou de 55% a 66% entre as referidas amostras, enquanto que o número de alelos por loco (Ae), variou de 1,0 a 5,0 , com uma média de 2,36 alelos por loco; o número efetivo de alelos variou de 1,0 a 2,2 alelos por loco. Quase todos os locos apresentaram-se em equilíbrio de Hardy-Weinberg, exceto Pgnil e Pgm2, cujos desvio foram significativos, (p<O,OI e p<O,OOI) nas amostras I e 11,respectivamente. A estatística F foi utilizada no presente trabalho considerando-se as quatro amostras como representativas de locais diferentes/.os valores de Frs e FSTnão diferiram de zero, confirmando achados anteriores. Com relação ao comprimento e perímetro das asas, verificou-se que existem diferenças significativas entre os períodos de coleta (p<0,05). Os menores valores para estas características ocorreram no inverno respectivamente 3,18cm e 7,Ocmpara machos, 3,05cm e 6,66cm para fêmeas; os maiores valores ocorreram no verão 3,58cm e 7,88cm (machos), 3,52cm e 7,80cm (fêmeas). Também foi demonstrado que existem diferenças entre os sexos, consistentes em todas as amostras sendo os machos, em média, maiores do que as fêmeas e apresentando uma menor variância para esta característica. Estas diferenças foram observadas em todas as amostras coletadas em ABE, e em outras localidades (HAAG & ARAÚJO, 1994). Tais diferenças parecem conferir uma maior autonomia de vôo aos machos e uma maior distância percorrida, bem como maiores chances de escape a predadores, além do que os capacitaria a atuarem como agentes dispersantes. Estudos adicionais,não constantes desta Dissertação, indicamque os machos pesam em média menos do que as fêmeas. Os achados até o momento sugerem, assim, possibilidade de seleção sexual, com as fêmeas escolhendo machos cujos tamanho e perímetro de asa sejam maiores, e próximos a um valor ótimo, implicandoem importantes conseqüências evolucionárias. / Dryas iulia is a butterfly that belongs to the subfamily Heliconiinae; it is usuaIly fomd in forest edges or clearings and among secondq vegetation. She prefer to fly in sunny places, one to three meters above the ground. Females lay their eggs on specil of Passifloraceae, particularly, in the outskirts of Porto Aiegre, on Passijlora suberosa and P. misera. This butterfly is abundant along the year except in the winter when the populations go dom nearly extinction. Their greater size normally occur in April and May . The genetic structure of D. iulia popdations fit the isol-ation by distance model. Previous estudies by HAAG (1992), HAAG et al. (1993) showed that Fst, values are not different from zero in several sampies ("populations") from Rio Grande do Sul, so also the inbreeding componente (Fis), although ilrimerically greater than the fomer. Ir, the present study sequencial sarnpling from Águas Belas was dom, in may and june 1992 and March and May 1993. These samples were narned I, II, III, and IV respectivelly. The area chosen belongs to the Viamão district and is mainly formed by secondary vegetation associate with Eucalyptm species. It was already included in tke work of HAAG (1992) where a non-randon association between the loci Est1 and Lap1 was described. Results for nine enzyrnatic loci (Mdh1, Mdh2, Pgm1, Pgm2, Aat1, Aat2, Est1, Est2, and a-Gpdh) showed similar values for tbe mean heterozygosity per locus per individual (H) in the four samples (0.097 sample I; 0.076 sample II; 0.103 sample III and 0.122 sample IV). The smaller values for H was found in winter- sample II - probaly due to loss of rare alleles. Only Pgm1 andj Pgm2 do not fitted the Hardy-Wehberg eguilibrium. The proportion of polymorphic loci (P) ranged from 0.55 to 0,66. The number of alleles per locus (A) was between 1 and 5 with an average of 2.36; the effective number of alleles (A) ranged from 1 to 2.2 per locus. Inter-sample comparisosns were made for alleles and genotypes distributions acording to the A statistics (SHIELDS & KEELER, 1979) for three distinct conditions: (a) all samples simultaneously; (b) between the two samples prior the winter bottleneck and (c) between the two samples after the winter. The loci Mdh1, Pgm2, Aatl and Est2 showed significant differences for at least one of the above situations. An analysis of the F statistics was perfomed as if the samples were a subdivision of a single popuiation. For both Fis and Fst no evidence was found to reject the null hypothesis. Morphological variation was measured by wing length and perimeter. An analysis of variance considering the four periods of study for each variable showed statistical differences (p < 0.05), with average for the winter being smaller for both sexes. For wing length these values were 3.18 cm (males) and 3.05 cm (females); for wing perimeter, 7.00 cm and 6.66 cm respectively. The largest values were observed in the summer, being 3.58 cm (males) and 3.52 cm (fedes) for wing length and 7.88 cm (males), 7.80 cm (females) for wing perimeter. Consistent differences (all samples) were verified between the sexes, males being greater than females, in the average and with smaller variance. The same was reported by HAAG and ARAÚJO (1994) within the Águas Belas populations as well as in relation tho other locallities. These findings are suggestive of a strong male ability to fly greater distances toescape predators, being responsible probably by a large proportion of the gene flow. On the other hand females would exert sexual selection through the choice of males with larger wings, perhaps dose to an optimum.

Dryas iulia pertence à subfamília HeliconitIae e é uma borboleta que prefere voar ao sol, sendo comumente encontrada em clareiras, bordas de florestas e matas secundárias. Ovoposita em espécies de Passifloraceae preferindo, em Porto Alegre e arredores Passiflora suberosa e P. misera (PÉRICO & ARAÚJO, 1991). É abundante durante quase todo o ano, excetuando-se os meses frios de inverno, quando suas populações virtualmente se extinguem. Geralmente o maior tamanho populacional é registrado nos meses de abril e maio. Do ponto de vista genético, Dryas iulia apresenta populações grandes e uniformes; em termos de estrutura genética elas se mostram compatíveis com o modelo do isolamento pela distância. Estudos realizados por HAAG (1992), HAAG e cols., (1993) mostraram que os valores de FSTnão diferiam de zero para várias amostras ("populações") do Rio Grande do Sul. O componente devido ao endocruzamento (FIs) também não diferiu de zero, embora seu valor numérico fosse mais elevado do que o esperado. No presente estudo investigou-se amostras seqüenciais (equivalentes a quatro gerações sucessivas) da região de Águas Belas, município de Viamão, RS, quanto a polimorfismos enzimáticos e variação morfológica. Originariamente os critérios para escolha deste local, foram a detcção, em trabalhos anteriores, por HAAG (1992), HAAG e cols., (1993), de uma situação altamente sugestiva de associação não aleatória entre dois locos enzimáticos (EST e LAP) nesta população, além das medidas lineares realizadas.nas asas anteriores mostrarem que os indivíduos dessa população são em média maiores quando comparados com os de outras. As amostragens ocorreram em maio de 1992, junho de 1992, março de 1993 e maio de 1993, (I, 11,111e IV amostras respectivamente). Baseado nos dados de polimorfismo enzimático para os locos Mdhl, Mdh2, Pgml, Pgm2, Aatl, Aat2, Estl, Est2 e a-Gpdh, a população local de D. iulia de Águas Belas apresentou, nas quatro amostras, os respectivos valores de heterozigosidade média por loco por indivíduo (Ho): 0,076 Gunho/92), 0,097 (maio/92), 0,103 (março/92) e 0,122 (maio/92). O menor valor para este parâmetro ocorreu no inverno, provavelmente por perda de alelos raros devido ao acaso. A proporção de locos polimórficos (P) variou de 55% a 66% entre as referidas amostras, enquanto que o número de alelos por loco (Ae), variou de 1,0 a 5,0 , com uma média de 2,36 alelos por loco; o número efetivo de alelos variou de 1,0 a 2,2 alelos por loco. Quase todos os locos apresentaram-se em equilíbrio de Hardy-Weinberg, exceto Pgnil e Pgm2, cujos desvio foram significativos, (p<O,OI e p<O,OOI) nas amostras I e 11,respectivamente. A estatística F foi utilizada no presente trabalho considerando-se as quatro amostras como representativas de locais diferentes/.os valores de Frs e FSTnão diferiram de zero, confirmando achados anteriores. Com relação ao comprimento e perímetro das asas, verificou-se que existem diferenças significativas entre os períodos de coleta (p<0,05). Os menores valores para estas características ocorreram no inverno respectivamente 3,18cm e 7,Ocmpara machos, 3,05cm e 6,66cm para fêmeas; os maiores valores ocorreram no verão 3,58cm e 7,88cm (machos), 3,52cm e 7,80cm (fêmeas). Também foi demonstrado que existem diferenças entre os sexos, consistentes em todas as amostras sendo os machos, em média, maiores do que as fêmeas e apresentando uma menor variância para esta característica. Estas diferenças foram observadas em todas as amostras coletadas em ABE, e em outras localidades (HAAG & ARAÚJO, 1994). Tais diferenças parecem conferir uma maior autonomia de vôo aos machos e uma maior distância percorrida, bem como maiores chances de escape a predadores, além do que os capacitaria a atuarem como agentes dispersantes. Estudos adicionais,não constantes desta Dissertação, indicamque os machos pesam em média menos do que as fêmeas. Os achados até o momento sugerem, assim, possibilidade de seleção sexual, com as fêmeas escolhendo machos cujos tamanho e perímetro de asa sejam maiores, e próximos a um valor ótimo, implicandoem importantes conseqüências evolucionárias. / Dryas iulia is a butterfly that belongs to the subfamily Heliconiinae; it is usuaIly fomd in forest edges or clearings and among secondq vegetation. She prefer to fly in sunny places, one to three meters above the ground. Females lay their eggs on specil of Passifloraceae, particularly, in the outskirts of Porto Aiegre, on Passijlora suberosa and P. misera. This butterfly is abundant along the year except in the winter when the populations go dom nearly extinction. Their greater size normally occur in April and May . The genetic structure of D. iulia popdations fit the isol-ation by distance model. Previous estudies by HAAG (1992), HAAG et al. (1993) showed that Fst, values are not different from zero in several sampies ("populations") from Rio Grande do Sul, so also the inbreeding componente (Fis), although ilrimerically greater than the fomer. Ir, the present study sequencial sarnpling from Águas Belas was dom, in may and june 1992 and March and May 1993. These samples were narned I, II, III, and IV respectivelly. The area chosen belongs to the Viamão district and is mainly formed by secondary vegetation associate with Eucalyptm species. It was already included in tke work of HAAG (1992) where a non-randon association between the loci Est1 and Lap1 was described. Results for nine enzyrnatic loci (Mdh1, Mdh2, Pgm1, Pgm2, Aat1, Aat2, Est1, Est2, and a-Gpdh) showed similar values for tbe mean heterozygosity per locus per individual (H) in the four samples (0.097 sample I; 0.076 sample II; 0.103 sample III and 0.122 sample IV). The smaller values for H was found in winter- sample II - probaly due to loss of rare alleles. Only Pgm1 andj Pgm2 do not fitted the Hardy-Wehberg eguilibrium. The proportion of polymorphic loci (P) ranged from 0.55 to 0,66. The number of alleles per locus (A) was between 1 and 5 with an average of 2.36; the effective number of alleles (A) ranged from 1 to 2.2 per locus. Inter-sample comparisosns were made for alleles and genotypes distributions acording to the A statistics (SHIELDS & KEELER, 1979) for three distinct conditions: (a) all samples simultaneously; (b) between the two samples prior the winter bottleneck and (c) between the two samples after the winter. The loci Mdh1, Pgm2, Aatl and Est2 showed significant differences for at least one of the above situations. An analysis of the F statistics was perfomed as if the samples were a subdivision of a single popuiation. For both Fis and Fst no evidence was found to reject the null hypothesis. Morphological variation was measured by wing length and perimeter. An analysis of variance considering the four periods of study for each variable showed statistical differences (p < 0.05), with average for the winter being smaller for both sexes. For wing length these values were 3.18 cm (males) and 3.05 cm (females); for wing perimeter, 7.00 cm and 6.66 cm respectively. The largest values were observed in the summer, being 3.58 cm (males) and 3.52 cm (fedes) for wing length and 7.88 cm (males), 7.80 cm (females) for wing perimeter. Consistent differences (all samples) were verified between the sexes, males being greater than females, in the average and with smaller variance. The same was reported by HAAG and ARAÚJO (1994) within the Águas Belas populations as well as in relation tho other locallities. These findings are suggestive of a strong male ability to fly greater distances toescape predators, being responsible probably by a large proportion of the gene flow. On the other hand females would exert sexual selection through the choice of males with larger wings, perhaps dose to an optimum.

Dryas iulia pertence à subfamília HeliconitIae e é uma borboleta que prefere voar ao sol, sendo comumente encontrada em clareiras, bordas de florestas e matas secundárias. Ovoposita em espécies de Passifloraceae preferindo, em Porto Alegre e arredores Passiflora suberosa e P. misera (PÉRICO & ARAÚJO, 1991). É abundante durante quase todo o ano, excetuando-se os meses frios de inverno, quando suas populações virtualmente se extinguem. Geralmente o maior tamanho populacional é registrado nos meses de abril e maio. Do ponto de vista genético, Dryas iulia apresenta populações grandes e uniformes; em termos de estrutura genética elas se mostram compatíveis com o modelo do isolamento pela distância. Estudos realizados por HAAG (1992), HAAG e cols., (1993) mostraram que os valores de FSTnão diferiam de zero para várias amostras ("populações") do Rio Grande do Sul. O componente devido ao endocruzamento (FIs) também não diferiu de zero, embora seu valor numérico fosse mais elevado do que o esperado. No presente estudo investigou-se amostras seqüenciais (equivalentes a quatro gerações sucessivas) da região de Águas Belas, município de Viamão, RS, quanto a polimorfismos enzimáticos e variação morfológica. Originariamente os critérios para escolha deste local, foram a detcção, em trabalhos anteriores, por HAAG (1992), HAAG e cols., (1993), de uma situação altamente sugestiva de associação não aleatória entre dois locos enzimáticos (EST e LAP) nesta população, além das medidas lineares realizadas.nas asas anteriores mostrarem que os indivíduos dessa população são em média maiores quando comparados com os de outras. As amostragens ocorreram em maio de 1992, junho de 1992, março de 1993 e maio de 1993, (I, 11,111e IV amostras respectivamente). Baseado nos dados de polimorfismo enzimático para os locos Mdhl, Mdh2, Pgml, Pgm2, Aatl, Aat2, Estl, Est2 e a-Gpdh, a população local de D. iulia de Águas Belas apresentou, nas quatro amostras, os respectivos valores de heterozigosidade média por loco por indivíduo (Ho): 0,076 Gunho/92), 0,097 (maio/92), 0,103 (março/92) e 0,122 (maio/92). O menor valor para este parâmetro ocorreu no inverno, provavelmente por perda de alelos raros devido ao acaso. A proporção de locos polimórficos (P) variou de 55% a 66% entre as referidas amostras, enquanto que o número de alelos por loco (Ae), variou de 1,0 a 5,0 , com uma média de 2,36 alelos por loco; o número efetivo de alelos variou de 1,0 a 2,2 alelos por loco. Quase todos os locos apresentaram-se em equilíbrio de Hardy-Weinberg, exceto Pgnil e Pgm2, cujos desvio foram significativos, (p<O,OI e p<O,OOI) nas amostras I e 11,respectivamente. A estatística F foi utilizada no presente trabalho considerando-se as quatro amostras como representativas de locais diferentes/.os valores de Frs e FSTnão diferiram de zero, confirmando achados anteriores. Com relação ao comprimento e perímetro das asas, verificou-se que existem diferenças significativas entre os períodos de coleta (p<0,05). Os menores valores para estas características ocorreram no inverno respectivamente 3,18cm e 7,Ocmpara machos, 3,05cm e 6,66cm para fêmeas; os maiores valores ocorreram no verão 3,58cm e 7,88cm (machos), 3,52cm e 7,80cm (fêmeas). Também foi demonstrado que existem diferenças entre os sexos, consistentes em todas as amostras sendo os machos, em média, maiores do que as fêmeas e apresentando uma menor variância para esta característica. Estas diferenças foram observadas em todas as amostras coletadas em ABE, e em outras localidades (HAAG & ARAÚJO, 1994). Tais diferenças parecem conferir uma maior autonomia de vôo aos machos e uma maior distância percorrida, bem como maiores chances de escape a predadores, além do que os capacitaria a atuarem como agentes dispersantes. Estudos adicionais,não constantes desta Dissertação, indicamque os machos pesam em média menos do que as fêmeas. Os achados até o momento sugerem, assim, possibilidade de seleção sexual, com as fêmeas escolhendo machos cujos tamanho e perímetro de asa sejam maiores, e próximos a um valor ótimo, implicandoem importantes conseqüências evolucionárias. / Dryas iulia is a butterfly that belongs to the subfamily Heliconiinae; it is usuaIly fomd in forest edges or clearings and among secondq vegetation. She prefer to fly in sunny places, one to three meters above the ground. Females lay their eggs on specil of Passifloraceae, particularly, in the outskirts of Porto Aiegre, on Passijlora suberosa and P. misera. This butterfly is abundant along the year except in the winter when the populations go dom nearly extinction. Their greater size normally occur in April and May . The genetic structure of D. iulia popdations fit the isol-ation by distance model. Previous estudies by HAAG (1992), HAAG et al. (1993) showed that Fst, values are not different from zero in several sampies ("populations") from Rio Grande do Sul, so also the inbreeding componente (Fis), although ilrimerically greater than the fomer. Ir, the present study sequencial sarnpling from Águas Belas was dom, in may and june 1992 and March and May 1993. These samples were narned I, II, III, and IV respectivelly. The area chosen belongs to the Viamão district and is mainly formed by secondary vegetation associate with Eucalyptm species. It was already included in tke work of HAAG (1992) where a non-randon association between the loci Est1 and Lap1 was described. Results for nine enzyrnatic loci (Mdh1, Mdh2, Pgm1, Pgm2, Aat1, Aat2, Est1, Est2, and a-Gpdh) showed similar values for tbe mean heterozygosity per locus per individual (H) in the four samples (0.097 sample I; 0.076 sample II; 0.103 sample III and 0.122 sample IV). The smaller values for H was found in winter- sample II - probaly due to loss of rare alleles. Only Pgm1 andj Pgm2 do not fitted the Hardy-Wehberg eguilibrium. The proportion of polymorphic loci (P) ranged from 0.55 to 0,66. The number of alleles per locus (A) was between 1 and 5 with an average of 2.36; the effective number of alleles (A) ranged from 1 to 2.2 per locus. Inter-sample comparisosns were made for alleles and genotypes distributions acording to the A statistics (SHIELDS & KEELER, 1979) for three distinct conditions: (a) all samples simultaneously; (b) between the two samples prior the winter bottleneck and (c) between the two samples after the winter. The loci Mdh1, Pgm2, Aatl and Est2 showed significant differences for at least one of the above situations. An analysis of the F statistics was perfomed as if the samples were a subdivision of a single popuiation. For both Fis and Fst no evidence was found to reject the null hypothesis. Morphological variation was measured by wing length and perimeter. An analysis of variance considering the four periods of study for each variable showed statistical differences (p < 0.05), with average for the winter being smaller for both sexes. For wing length these values were 3.18 cm (males) and 3.05 cm (females); for wing perimeter, 7.00 cm and 6.66 cm respectively. The largest values were observed in the summer, being 3.58 cm (males) and 3.52 cm (fedes) for wing length and 7.88 cm (males), 7.80 cm (females) for wing perimeter. Consistent differences (all samples) were verified between the sexes, males being greater than females, in the average and with smaller variance. The same was reported by HAAG and ARAÚJO (1994) within the Águas Belas populations as well as in relation tho other locallities. These findings are suggestive of a strong male ability to fly greater distances toescape predators, being responsible probably by a large proportion of the gene flow. On the other hand females would exert sexual selection through the choice of males with larger wings, perhaps dose to an optimum.

Les céréales domestiques, blé et orge, sont apparues sur plusieurs sites éloignés du Proche-Orient à partir de précurseurs sauvages originaire d'Anatolie. Cette thèse propose que la domestication de ces céréales est le résultat de quatre étapes successives et indépendantes: 1) au Natoufien ancien, une sédentarisation a augmenté la fertilité en rapprochant les naissances. Ceci a créé un nouveau besoin en aliments de sevrage qui a rendu les céréales indispensables comme ressource alimentaire. La croissance démographique a fait évoluer la structure sociale des communautés des groupes familiaux à des groupes locaux; 2) au Natoufien récent, la crise environnementale du Dryas récent a obligé certaines communautés à combler leurs besoins en céréales avec les premières mises en culture. Ces communautés ont réussi à maintenir leur vie sédentaire, leur population et leurs capacités technologiques en rigidifiant leur structure sociale en chefferies; 3) au PPNA, une expansion coloniale des communautés qui ont survécu au Dryas récent a transplanté les céréales sauvages dans l'ensemble du Proche-Orient en les adaptant à des sols et des climats nouveaux; 4) au PPNB, la recherche d'une plus grande productivité et un heureux hasard ont fait apparaître les céréales domestiques sur quelques sites. La domestication des céréales au Proche-Orient est donc le résultat d'un processus évolutif qui a modifié à la fois le contexte socio-culturel des communautés humaines et leur relation aux céréales. / Domestic cereals, wheat and barley, appeared at several distant sites in the Near East from wild progenitors from Anatolia. This thesis suggests that domestication of these cereals was the result of four successive and independant steps: 1) during early Natufian, sedentarisation raised fertility by decreasing the time inteval between consecutive births. This created a new need for weaning foods, so that cereals became a necessary part of subsistance. The increase in population led the social structure of communities to evolve from family groups into local groups; 2) during late Natufian, the Younger Dryas environmental crisis forced some communities to meet their needs for cereals by initiating their first cultivations. These communities could remain sedentary and maintain both their population and their technological potential by rigidifying their social structures into chiefdoms; 3) during PPNA, a colonial expansion of communities that survived the Younger Dryas transplanted wild cereals throughout the Near East and adapted them to new soils ans climates; 4) during PPNB, the search for an increased productivity and some chance led to the appearance of domestic cereals at some sites. Cereal domestication in the Near East thus appears as resulting from an evolutionary process which modified both the socio-cultural context of human communities and their relationship to cereals.

Sveriges geomorfologi har till största del bildats under den senaste glaciationens erosion och depositions processer. Vid denna glaciations avsmältning rann smältvattnet bort från glaciären i isälvarna genom tunnlar under inlandsisen. Från dessa isälvar bildas åsar när materialet som transporterats med glaciären förs med i det turbulenta flödet i isälven innan det avsätts och bygger upp dessa långsträckta terrängformer. Isälvarnas position under inlandsisen bestäms av hydrauliska potentialen vilken bestämmer rörelseriktningen för vatten under glaciären. I vissa områden kommer den ha en lägre potential och andra en högre potential beroende på isens tjocklek och formen av den underliggande terrängen. Där den hydrauliska potentialen konvergerar kommer isälvar bildas av de stora mängder smältvatten som transporteras bort. Syftet med detta projekt var att bekräfta åsbildningen i Svealand genom att göra en modellering av den hydrauliska potentialen under inlandsisen i ArcGIS. Två modelleringsalgoritmer för flödesriktning kallade D8 och D-infinity, jämfördes också för att avföra vilken av dessa som bäst modellerar smältvattnets flödesvägar under inlandsisen. Tidsintervallen 11 000, 12 000 och 13 000 år sedan valdes för denna undersökning då inlandsisen då gick från att ligga strax söder om Svealand till mellersta Svealand. Mellan 11 000 och 10 000 år sedan avsmälte glaciären väldigt hastigt och retirerade till Kaledoniderna i norra Sverige och används därför ej i denna undersökning.   I ArcGIS beräknades hydropotentialen för de olika tidpunkterna varefter sänkor i rastret fylldes upp. Flödesriktningen och flödesackumulationen beräknades för både D8 och D-infinity. Från flödesackumulationen togs isälvarna fram genom en omklassning av rastret. För att avgöra vilken flödesriktningsalgoritm som modellerade smältvattnets flödesvägar under inlandsisen bäst användes ett verktyg som summerade antalet pixlar av isälvar som låg under polygoner över nutida åsar i Svealand. Från detta beräknades en procentskillnad mellan D8 och D-infinity för att avgöra vilken av dem som stämde bäst överens med de nutida åsarna. En karta för varje tidsintervall som undersöktes samanställdes med de modellerade isälvarna och de nutida åsarna i Svealand för att visuellt avgöra om det gick urskilja en kronologisk bildningsföljd av åsarna.  D-infinity beräknades modellera isälvarna upp till 2,5 procentenheter bättre än D8. Skillnaden mellan modelleringsalgoritmerna minskade i takt med att glaciärtäckningen av Svealand minskade. I kartorna som sammanställdes gick en viss kronologisk trend att se. Vissa åsar som när de låg långt från inlandsisens kant blev inte modellerade som isälvar förrän inlandsisens kant kom närmare dem. Vissa modellerade isälvar låg inte direkt på de nutida åsarna utan lite till sidan av dem vilket skulle kunna bero på att den rumsliga upplösningen som modelleringen gjordes i var för grov eller att fler faktorer behöver tas med i modelleringen. Till exempel skulle snävare tidsintervall kunnat användas i modelleringen för att bekräfta den kronologiska bildningsföljden av åsar. Transmissivitetens koppling till den hydrauliska potentialen och avståndet mellan isälvar hade möjligtvis också förbättrat modelleringen av isälvarnas rumsliga position. / Sweden's geomorphology has largely been formed during the recent glaciation erosion deposition processes of recent glaciation. During the deglaciation, the meltwater ran away from the glacier in the channel ice streams through tunnels under the ice sheet from which eskers were formed. The position of the glaciers in the ice sheet is determined by the hydraulic potential, which determines the direction of movement of water below the glacier. In some areas, it will have a lower potential and others a higher potential depending on the thickness of the ice and the shape of the underlying terrain. In places where the hydraulic potential converges, ice rivers will be formed by the large amounts of melt water transported away. The purpose of this project was to confirm the esker formation in Svealand by modelling the hydraulic potential during the glaciation in ArcGIS. Two flow direction modelling algorithms, D8 and D-infinity, were also compared to determine which of these best models the meltwater flow paths under the ice sheet. The years 11,000, 12,000 and 13,000 years ago were chosen for this study as the ice sheet then went from lying just south of Svealand to central Svealand. Between 11,000 and 10,000 years ago, the glacier melted very rapidly and retreated to the Caledonids in northern Sweden and is therefore not used in this study. In ArcGIS, the hydraulic potential for the different time intervals was calculated, after which sinks in the grid were filled up, the flow direction and the flow accumulation were calculated for both D8 and D-infinity. From the flow accumulation, the channel ice streams were generated by a reclassification of the grid. To determine which flow direction algorithm best modelled the meltwater flow paths under the ice sheet, a tool was used that summed the number of pixels of channel ice stream that were below polygons over current eskers in Svealand. From this, a percentage between D8 and D-infinity was calculated to determine which of them best matched the current eskers. A map for each assessed year was compiled with the modelled channel ice streams, ice sheet edge and the current eskers in Svealand to visually determine whether a chronological sequence of the eskers could be discerned. D-infinity was estimated to model the channel ice streams up to 2.5 percentage points better than D8. The difference between the modelling algorithms decreased as the glacier coverage of Svealand decreased. In the maps that were compiled, a chronological trend could be inferred to a certain point. Some eskers that, when they were far from the edge of the ice sheet, were not modelled as channel ice streams until the edge of the ice sheet were much closer to them. The modelling could be improved by increasing the resolution in which the modelling was made as it might have been too coarse or that more factors need to be included in the modelling. For example, narrower time intervals could be used in the modelling to confirm the chronological sequence of ridges. The connection between the transmissivity and the hydraulic potential and the distance between ice rivers may have also improved the modelling of the spatial position of the ice rivers.

This thesis uses geological field data and numerical ice sheet modelling to study the Younger Dryas ice cap in Scotland. The Younger Dryas stadial is important because it represents the most recent period of high-magnitude global climate change, and was marked by the expansion of ice sheets in North America and Scandinavia, and the regrowth of glaciers in the British Isles. An integrated methodology linking field results and modelling is developed and applied here, specifically focussing on the deposits, landforms, and palaeoglaciology of Younger Dryas glaciers in western Scotland. This combined approach enables data of different scales to be compared, and connected, from local sedimentological investigations and empirically derived reconstructions, to regional ice-sheet simulations from a high-resolution numerical model. Previous geological mapping in western Scotland resulted in contradictory views of the thickness and extent of ice during the Younger Dryas, consequently leading to uncertainty about the dynamics of the former ice cap. By using a ‘landsystem’ method to characterise the terrain, it is argued here that geological evidence in the study area implies a relatively thick central ice cap that fed steep outlet glaciers around its margins. These glaciers oscillated throughout the stadial, and during deglaciation produced suites of moraines that marked successive positions of glacier retreat. Widespread preservation of superimposed landforms, and of sediment sequences pre-dating the Younger Dryas, suggest that, despite being active, the Younger Dryas ice cap was not particularly erosive in its central area and only subtly modified its bed. These geological interpretations are supported by high-resolution numerical modelling of the ice cap, which reveals clear spatial variability in the velocity structure, thermal regime, and flow mechanism of the ice cap; patterns that led to local contrasts in basal processes and diversity in the geological imprint. These model experiments also highlight the non-linear relationship between climate forcing and glacier response, identifying evidence of ice sheet hysteresis and climatically decoupled glacier oscillations – concepts as relevant to geological investigations of former ice masses as they are to the prediction of glacier response under future climate changes.