Zoo - week 1

- Diet and ecological food chains

what is a primary producer?

producer of energy at the bottom of a food chain

what animals are most often primary consumers?

herbivores

what animals are most often secondary consumers?

carnivores

what animals are most often tertiary consumers?

apex predators

what percentage of biomass is lost at each trophic level?

about 90%, which means that only 10% of energy gets transferred

why do terrestrial ecosystems have lots of plants?

primary consumers need to eat a lot of it in order to stay alive

what are the consequences of farm fishing for sustainability?

farmed fish eat other farmed fish, disturb the food chain.

why are most farmed fish omnivores?

it’s easier to feed them and they need less space

why are rainforests less efficient in producing biomass?

the primary producers grow less well because of the lack of sunlight (shaded by the trees)

what is different about the pyramid in aquatic ecosystems?

the pyramid is upside down; apex predators have the most biomass

why do apex predators have the most biomass in the aquatic ecosystem?

the lifespans of algae (primary producers) are very short. They stay very small but grow in large numbers

in what ecosystem are humans higher on the trophic chain? aquatic or terrestrial?

aquatic, humans rarely eat aquatic plants but often eat terrestrial plants

what is important to know about tuna capture?

tuna are a migrating species, so they could only be caught in specific seasons. This required knowledge on the migration season and catching technique

why are lumpfish cool?

they’re used in farms to clean other fish and provide a symbiotic relationship with the farmer (lumpfish gets fed with lice, farmer’s fish stay clean)

what are 4 reasons we should want to know what people ate?

1. it tells us about their environment

2. it tells us about their techniques and knowledge

3. it tells us about their priorities, beliefs and taboos

4. it tells us about how people spent their days

what are 2 ways to investigate diet?

1. quantifiying zooarchaeological remains

2. stable isotope analysis

what 2 materials are sampled for stable isotope analysis?

1. apatite

2. collagen

what can we learn from isotopic signatures?

1. the migration of species (Sr)

2. food chains and dietary changes of animals (C, N)

3. The age and quality of water bodies (O)

4. the origins of water and atmosphere pollution (S?)

why are there higher nitrogen levels in aquatic ecosystems?

there are more trophic steps in the food web (more chances to increase N in specimen)

what 2 things should you take into account when reconstructing pyramids and food chains?

1. food chains are super simplistic

2. food webs are way messier