Climate change and tetrapod evolution Flashcards
what is meant by the terms climate and weather
Weather = measured over days, months and seasons (over short period of time)
Climate = weather statistics measured over a long period of time
“climate is what you expect, weather is what you get”
outline some of the sources of information which can be used about the past climate conditions
1) sedimentary rock = the presence or absence of water, marine life, sedimentary deposits or magnesium/calcium rations
2) ice cores = go back 10/1000s of years, air trapped in frozen bubbles, oxygen isotope indicate ocean surface temperatures, pollen and volcanic ash
3) Tree rings = information about rainfall etc such as droughts
outline changes in global temperature during tetrapod evolution
1) Tetrapods emerge from the sea when the planet was warm as a result of decreased prodcutvity from water and increased on land = 400 million years B4 present
2) Carboniferous rainforest collapse lead to extinction of many amphibians and the evolution and diversification of amniotes who were better adapted for cold and dier conditions as the temp dropped
3)Temp begins to rise and drop again= cooling climate and expansion of grassland incenozoic correlates with increasing mammalian body size = ~45 mya
4) temperature relativley stabel in last 1000 years but beginning to rise again
what is meant by the term contemporary climate change
refers to the ongoing, current changes in Earth’s climate patterns that are largely attributed to human activities, particularly the increase in greenhouse gas emissions. The term “contemporary” emphasizes that these changes are occurring in the present
outline the distribution pattern of tetrapod on earth and how it is changing with climate change
most diverse in tropical areas and Himalayan regions showing a strong latitudinal trend with higher diversity surrounding equitorial regions
WITH CLIMATE CHANGE
= the percentage of species in decline is greatests in higher latitudes such as greenland etc than lower latitudes
what are some reasons for the differences in % tetrapod decline across the globe
climate change
global industrialised north
habitat loss
overexploitation
biological invasions
pollution
outline the IUCN summary of the effect of climate change on tetrapod
Habitat loss accounts for 75% of mammalian decline compared to climate change which counts for only 10%
- some species are effected by factors more or less than others e.g. migratory birds due to foraging grounds being under threat e.g. artic areas
overexploitation e.g. food and pets effects mammals more than reptiles
outline Urban 2015 study relating to extinction risk and climate change
a meta-analysis of 130 studies that predict extinction risk due to climate change
- studies estimate correlations between spp distributions and climate to predict suitable habitats under future climates
- exinctions occur if the range falls below threshold
= found extinctions are accelerating as temp rises and some areas such as NZ are partoculary effected as small land masses = no simple habitat shift
what perspectives have the effects of climate change been studied from
- species distributions
- community composition
- extinction risk
= move, adapt or die aka shift range, populations adapt or die
what are the strategies which can be used to see what life will be like following climate change
1) investigate evolutionary responses to extreme weather events
2) longitudinal studies
3) paleontological studies
what is meant by an extreme weather event
condensed climate change = when change occurs in a period of days rather than years/decades
= becoming more frequent and extreme
outline what Bumpus did in 1898 to investigate animal evolution following extreme weather
- housed sparrows which had survived a severe winter storm and found that they had less extreme morphologies
- this was one of the first demonstarting natural selection
= Natural selection is most destructive of those birds which have departed from the ideal type, and its activity raises the general standard of excellence by favoring those birds which approach the structural ideal’
outline Campbell-Stratton et al 2017 study looking at genomics and extreme weather
study conducted during extreme polar vortex in 2013 covering north america meaning lizards faced colder weather than usual
= took genomic samples and focused on regulatory genes responsible for setting traits involved in thermotolerance of the spp
= found populations and the southern site more able to keep up with the weather
outline an example of using lognitudinal studies for looking at the impact of climate change on tetrapods
Great tit laying date
= warming climate meant the hatching of lepidopteran eggs earlier
= tits whcih lay earlier have higher fitness as there is more food availability for young
= early offspring go onto produce more offspring that late laying offspring
what is Bergmanns rule
body size increases at high latitudes or low temperatures
