lecture 10 - how do organisms acquire energy? heterotrophs

Question 1

heterotrophy

Answer 1

use organic sources of carbon synthesized by others to derive energy (eat other organisms/organic material)

Question 2

which organismal group can heterotrophy be found in

Answer 2

all organismal groups

Question 3

herbivores

Answer 3

organisms that eat plants

Question 4

carnivores

Answer 4

organisms that eat animals

Question 5

detritivores

Answer 5

organisms that eat dead organic matter (it used to be alive but is no longer living)

Question 6

food economics

Answer 6

heterotrophs need to balance ease of getting food and food quality

Question 7

ecological stoichiometry

Answer 7

the balance of these five elements in ecological interations

Question 8

what are the five elements for ecological stoichiometry

Answer 8

carbon, oxygen, hydrogen, nitrogen, phosphorous

Question 9

carbon (food stoich)

Answer 9

provides structure to organisms

Question 10

oxygen (food stoich)

Answer 10

part of water molecules (organisms mostly made of water)

Question 11

hydrogen (food stoich)

Answer 11

other part of water molecules

Question 12

nitrogen (food stoich)

Answer 12

part of amino and nucleic acids

Question 13

phosphorous (food stoich)

Answer 13

essential for cellular processes such as ATP energy transfer

Question 14

what is the C:N abundance in plants

Answer 14

high carbon and nitrogen ratio (lots of carbon to build up structure)

Question 15

what is the C:N abundance in animals, fungi, and bacteria

Answer 15

low carbon and nitrogen ratio (structural components are less carbon rich)

Question 16

what does the carbon and nitrogen ratio dictate

Answer 16

what and how much each type of heterotroph needs to eat

Question 17

what is the ease balance of herbivory

Answer 17

getting food is easy but the quality of the food is low

Question 18

nutritional chemistry

Answer 18

high C:N ratio means plants (particularly those high with lots of cellulose and lignin) are difficult to ingest and digest
there are adaptations to teeth and digestive systems though

Question 19

plant defence

Answer 19

plants fight back with adaptations to deter herbivory
physical (thorns and spines) and/or chemical (alkaloids, cyanide, tannins)

Question 20

how does herbivory compensate

Answer 20

compensates for low nutritional quality by eating A LOT

Question 21

what is the ease balance for carnivory

Answer 21

ease of getting the food is low and the quality of the food is high

Question 22

what are the pros to carnivory

Answer 22

a predator can use multiple prey species and get the same nutrition
strong selection to efficiently capture and consume prey (adaptations and natural selection)

Question 23

what are the cons to carnivory

Answer 23

little variation in C:N ratio across animal species
eating animals is one of the easiest ways to meet nutritional needs as long as the animal can catch them

Question 24

what is the ease balance for detritivores

Answer 24

ease of getting the food is plus or minus to the quality of the food

Question 25

how do decomposers consume food

Answer 25

they do not ingest but can directly absorb nutrients through chemical and biological processes (not all of them ingest + digest food)

Question 25

how do detritivores consume food

Answer 25

must ingest and digest dead organic matter via internal processes

Question 26

what elements are dead plants rich in

Answer 26

rich in carbon and energy but low in nitrogen

Question 27

what are detritivores limited by

Answer 27

abiotic factors and the chemical composition of the detritus

Question 28

mixotrophy/omnivore

Answer 28

mixotrophs can gain energy from photosynthesis (inorganic) and from consuming organic matter. omnivores gain energy from both plant and animal matter

Question 29

how to measure energy limits in plants

Answer 29

photosynthesis reaches a plateau above Isat (max ability to photosynthesize)

Question 30

how to measure energy limits in animals

Answer 30

food intake saturates at a certain level of food density

Question 31

what is the relationship between good density and feeding rate

Answer 31

functional response curves (i-iii)