Lecture 3 & 4: Organisms - Adaptation to the physical environment

Question 1

what is heritable variation

Answer 1

• 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

Question 2

what is natural selection

Answer 2

Differential survival and reproduction of individual organisms, dictated by the interactions between the organism’s traits and the environment

Question 3

what are adaptations

Answer 3

• 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

Question 4

define evolution

Answer 4

change in genotypes within a population of a species over time

Question 5

what are the key properties of water

Answer 5

1. Liquid under most temperatures on earth, but with unusual freezing properties
2. High viscosity and an excellent medium for locomotion.
3. High capacity for dissolving inorganic compounds and providing a medium for nutrient uptake and exchange

Question 6

explain the thermal properties of water

Answer 6

• 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

Question 7

explain the destructive power of freezing water

Answer 7

• 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

Question 8

Locomotion and the density (viscosity) of water

Answer 8

• 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.

Question 9

what is convergent evolution

Answer 9

two or more species descended from distantly related ancestors evolve similar adaptations to common environmental challenges

Question 10

Convergent air-filled bladders in kelp and fish

Answer 10

• 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

Question 11

Convergent adaptations for locomotion

Answer 11

many sea mammals have a torpedo like shape in order to help move through water

Question 12

explain water as a solvent and medium for nutrients

Answer 12

• 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.

Question 13

Water movement in plants & the environment

Answer 13

• 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

Question 14

define transpiration

Answer 14

Water is pulled off leaf surface cells by evaporation in plants

Question 15

Water balance in freshwater animals

Answer 15

• 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

Question 16

Water balance in marine (salt water) animals

Answer 16

• 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

Question 17

adaptation to salt water tolerance in sharks

Answer 17

• 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

Question 18

Human impacts on salt balance in nature

Answer 18

• 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

Question 19

what are the benefits of heat

Answer 19

-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

Question 20

what happens to an organism when heat is increased?

Answer 20

destabilize proteins and break the proteins function in chemical pathways

Question 21

Humans and thermal pollution in aquatic systems

Answer 21

• 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

Question 22

what is coral bleaching?

Answer 22

-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

Question 23

Humans and thermal pollution in marine systems

Answer 23

-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

Question 24

what is radiation

Answer 24

-Emission of electromagnetic energy by a warm surface
-can be absorbed by a cooler surface

Question 25

what is conduction

Answer 25

Transfer of heat via direct contact between surfaces.

Question 26

what is convection

Answer 26

Transfer of heat by movement of liquids or gases

Question 27

what is evaportation

Answer 27

Water loss takes energy with it

Question 28

define endotherms

Answer 28

they actively maintain body temperatures

Question 29

define ectotherms

Answer 29

tolerate external environmental temperatures

Question 30

short-term blood shutting

Answer 30

-Reducing and redirecting blood flow before it reaches cold extremities

Question 31

cold-tolerance adaptation in mammals

Answer 31

mammal hairs stand up when they’re cold bc that can trap the air that needs to be heated

Question 32

Endotherm with extreme freeze-prevention adaptations

Answer 32

-they have a countercurrent heat exchange
-these organisms maintain blood flow while reducing heat loss in tissues that can tolerate colder temperatures

Question 33

phenotypic plasticity

Answer 33

-The ability of a single genotype to produce multiple phenotypes
-driven by phenotypic trade-offs
-can be reversible or irreversible

Question 34

what are physical adaptations?

Answer 34

-adaptations for fluctuating environments
-differential enzyme production
-seasonal changes in trait expression
-torpor and hibernation

Question 35

behavioral adaptations

Answer 35

• an adaptation to a fluctuating environment
• short-term and local: microhabitat use
• long-term and regional: migration

Question 36

example of differential enzyme production

Answer 36

trout: in the colder months, the winter isozyme works best while in the warmer months, the summer isozyme works best

Question 37

example of seasonal changes in trait expression.

Answer 37

• 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

Question 38

what is torpor

Answer 38

-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.

Question 39

example of torpor

Answer 39

-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

Question 40

hibernation

Answer 40

-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

Question 41

Microhabitat

Answer 41

Locations within a larger habitat that contain favorable abiotic conditions for the organism.

Question 42

environmental filtering

Answer 42

-driven by differences in microhabitats
-abiotic conditions within a microhabitat exclude certain organisms that might otherwise be abundant in the larger habitat.

Question 43

migrations

Answer 43

-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

Question 44

examples of migrations

Answer 44

-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