Lecture 3 & 4: Organisms - Adaptation to the physical environment Flashcards
what is heritable variation
- Differences/variation in the DNA within individual dictates the nature of ecological interaction for that particular organism
- some heritable variations are favored by the environment which then results in those organism with that variation to survive more and produce more
what is natural selection
Differential survival and reproduction of individual organisms, dictated by the interactions between the organism’s traits and the environment
what are adaptations
- Traits of an organism that have evolved over time and improve the fit of members of a population to their environment.
- Environmental and abiotic factors challenges are a major driver of adaptive change
define evolution
change in genotypes within a population of a species over time
what are the key properties of water
- Liquid under most temperatures on earth, but with unusual freezing properties
- High viscosity and an excellent medium for locomotion.
- High capacity for dissolving inorganic compounds and providing a medium for nutrient uptake and exchange
explain the thermal properties of water
- water is stable, heat changes will not make water unstable
- all organisms have adaptations to deal with liquid water conditions bc liquid water dominates
- water becomes less dense as it approaches freezing and it expands
- surface of large bodies of water do not freeze and ice does not sink
explain the destructive power of freezing water
- properties of freezing water place an overarching
restriction on adaptations - freezing must be avoided internally and externally
- All individuals in all environments must be adapted to avoid freezing water
Locomotion and the density (viscosity) of water
- density provides support for organisms internally and externally
- Density provides resistance for locomotion, which causes challenges for movement
- Active movement or positioning of water-filled organisms in water requires adaptation.
what is convergent evolution
two or more species descended from distantly related ancestors evolve similar adaptations to common environmental challenges
Convergent air-filled bladders in kelp and fish
- kelp have air filled bags to keep them anchored in the sea floor in order to grow upward and go through photosynthesis
- fish have air filled bags to move up and down without the density of water stopping it
Convergent adaptations for locomotion
many sea mammals have a torpedo like shape in order to help move through water
explain water as a solvent and medium for nutrients
- Water is a medium to dissolve nutrients and move them around in the environment due to its solvent properties
- provides a medium for reactions, to create compounds
- Water molecules carry charge that is attracted to charges on solids.
- Bodies of freshwater strip material and redistributes them to the ocean
- Oceans concentrate dissolved elements.
Water movement in plants & the environment
- osmosis forces water into the xylem in the roots
- transpiration can exceed the rate of water delivery by osmosis so to counteract this, the stomata slow the loss of water and keeps the process in balance
define transpiration
Water is pulled off leaf surface cells by evaporation in plants
Water balance in freshwater animals
- hyper-osmotic – potential to pull in too
much water because internal solute concentrations are higher - continuously excreting water in their urine
- salts are selectively taken up by gills and filtered in kidneys
Water balance in marine (salt water) animals
- hypo-osmotic - potential to lose too much water because external solute concentrations are higher
- must drink lots of sea water and actively excrete the salts
adaptation to salt water tolerance in sharks
- it up-regulates the amount of urea in its blood to match the amount in the ocean but urea is really toxic in the body
- counter adaption: it can withstand high urea concentration
Human impacts on salt balance in nature
- Salt concentration in freshwater are higher than normal near roads bc humans put salt in the road during winter and it runs into the lakes
- This causes a decline in freshwater organisms due to larger salt concentration due to human driven disruption in the osmotic conditions the species are adapted to
what are the benefits of heat
-causes organic molecules to move and change shape which can speed chemical reactions and improve organism performance.
-benefits only exist in a narrow temperature range
what happens to an organism when heat is increased?
destabilize proteins and break the proteins function in chemical pathways
Humans and thermal pollution in aquatic systems
- bc industrialization factories use water for cooling and end up dumping the heated water back into freshwater
- this causes many aquatic organisms to die due to them having narrow optimal/favorable temperature ranges
what is coral bleaching?
-corals live in a mutualistic relationship with algae, the algae allows the coral to gain nutrients from photosynthesis
-when water temperature increases, the algae will die and leave the coral white/bleached
Humans and thermal pollution in marine systems
-human activity has caused an increase in CO2 emissions that get absorbed by the ocean causing it to become warmer
-this then kills off the algae
-the coral can still feed on floating organisms near it but it will not survive in the long run bc there is no photosynthesis taking place
what is radiation
-Emission of electromagnetic energy by a warm surface
-can be absorbed by a cooler surface
what is conduction
Transfer of heat via direct contact between surfaces.
what is convection
Transfer of heat by movement of liquids or gases
what is evaportation
Water loss takes energy with it
define endotherms
they actively maintain body temperatures
define ectotherms
tolerate external environmental temperatures
short-term blood shutting
-Reducing and redirecting blood flow before it reaches cold extremities
cold-tolerance adaptation in mammals
mammal hairs stand up when they’re cold bc that can trap the air that needs to be heated
Endotherm with extreme freeze-prevention adaptations
-they have a countercurrent heat exchange
-these organisms maintain blood flow while reducing heat loss in tissues that can tolerate colder temperatures
phenotypic plasticity
-The ability of a single genotype to produce multiple phenotypes
-driven by phenotypic trade-offs
-can be reversible or irreversible
what are physical adaptations?
-adaptations for fluctuating environments
-differential enzyme production
-seasonal changes in trait expression
-torpor and hibernation
behavioral adaptations
- an adaptation to a fluctuating environment
- short-term and local: microhabitat use
- long-term and regional: migration
example of differential enzyme production
trout: in the colder months, the winter isozyme works best while in the warmer months, the summer isozyme works best
example of seasonal changes in trait expression.
- dogs, american bison, and buffalo: in the warmer months, they grow a lot of hair while in the colder months, they shed their hair to prevent overheating
what is torpor
-the ability for an organism to switch to low energy state in cold conditions when high activity is not needed
-used by endotherms
-voluntary and reversible
-a short-term solution.
example of torpor
-hummingbirds: when torpid (non-active) not a lot of energy is used and as the temperature increases, the amount of energy used decreases to prevent overheating
-when active a lot of energy is used (more than torpid) and as the temperature increases, the energy used also decreases
hibernation
-an adaptation to the higher energetic costs of activity and temperature maintenance in colder conditions with scarce food
-complete inactivity, heart rate reduction, and lower body temperature allow the animal to survive long periods from stored fat
Microhabitat
Locations within a larger habitat that contain favorable abiotic conditions for the organism.
environmental filtering
-driven by differences in microhabitats
-abiotic conditions within a microhabitat exclude certain organisms that might otherwise be abundant in the larger habitat.
migrations
-Seasonal movement of animals from one location to another at regional spatial scales
-Driven by substantial seasonal shifts in abiotic conditions and associated resource supplies
-Individual organisms may do the first part of migration and their offspring will complete the rest
examples of migrations
-monarch butterflies
-they migrate south to Mexico for the winter where they hibernate
-then they migrate back north as summer approaches and mate along the way and the offspring complete the full migration
-once the offspring are north, the mate again and the offspring migrate back south for the winter
