Food Chains and Research Studies

Question 1

Producers –> autotrophs

Answer 1

plants, algae, phytoplankton (photosynthesis)
make their own food
create chemical energy from solar energy
photosynthesis= H2O +CO2 –light–> sugars + O2

Question 2

Primary Consumers –> heterotrophs

Answer 2

herbivores (eat plants and algae)

eat their food

Question 3

Secondary consumer

Answer 3

omnivores/ carnivores (eat herbivores)

Question 4

Tertiary consumers

Answer 4

omnivores/carnivores (eat omnivores/ carnivores)

Question 5

Apex Predators

Answer 5

tertiary consumer with no predators

often vital to ecosystem (keystone species)

Question 6

Decomposers

Answer 6

bacteria and fungi
break down decomposing plants/animals
release inorganic nutrients back into the environment

Question 7

Direct Observation

Answer 7

Pros- generally inexpensive

Cons-

• difficult wit crepuscular/ nocturnal/ fossorial species
• difficult with aquatic animals
• difficult in certain environment
• no indication as to what the animal is doing when not observed
• very time consuming

potenial issues
- animals do not always eat the whole food item

Question 8

Utilization studies- Enclosure

Answer 8

pros

• relatively simple to perform
• gives indication of which plant species/ parts were eaten

cons

• only useful for herbivores
• other animals may have eaten from the enclosure

Question 9

Utilization studies- cafeteria- captive animals

Answer 9

pros

• relatively simple to perform
• gives indication of which plant species/ part were eaten
• gives indication of plant species/ part preference

Cons

• animals are captive and cannot range/forage freely
• may not capture all plant parts (roots, stems)

Question 10

Digesta Sampling: Fistulation

Answer 10

pros

• more accurate than utilization techniques
• can identify proportion/types of feed

Cons

• only works with captive (and tame) animals
• may not be a true representation of a wild diet
• surgical procedure required to implant fistula

Question 11

Digesta Sampling: pellets

Answer 11

pros

• more accurate than utilization techniques
• non-invasive

cons

• some food components are poorly represented or absent
• only useful for birds
• some bird species do not necessarily eat whole prey

pellets contains only indigestible components of foods eaten:

• bones: provide species, size , age of prey
• feathers: provide species and age of prey
• scales: provide age and class of prey

Question 12

Digesta Sampling: Postmortem

Answer 12

pros

• more accurate than utilization techniques
• no animals killed specifically for the procedure/study

cons

• time of last meal unknown
• degree of digestion unknown

Question 13

Fecal Analysis

Answer 13

pros
- may provide information not attained via utilization techniques
- non-invasive
cons
- only poorly digested food components are represented
- may be difficult to ID the species the produced the faces

Question 14

Stable Isotope Studies

Answer 14

every biologically active element exists in various isotopic forms;

• isotopes differ based on # of neutrons in the nucleus
• two or more isotopes of each element are stable

Question 15

Adipose Tissue composition

Answer 15

fats stored as adipose tissue reflect fats consumed by the animal
except in ruminants/ foregut fermenters who can hydrogenate fatty acids
microbes in fermentation may produce unusual fatty pics