4.7 Evolution of the Digestive System

Question 1

Main purpose of the digestive

Answer 1

• obtain and convert nutrients into usable energy (ATP)
• to perform all necessary cellular functions.

Question 2

Two main mechanisms of getting nutrients

Answer 2

AUTOTROPHS
&
HETEROTROPHS

Question 3

What is Autotrophs

Answer 3

• use energy to build organic molecules by photosynthesis;
• cellular respiration to release that energy as ATP

Question 4

2 types of Autotrophs

Answer 4

• > Photoautotrophs: use solar energy
• > Chemoautotrophs: use chemical energy

Question 5

What is Heterotrops

Answer 5

• variety of feeding devices and behaviours to obtain nutrients

Question 6

Mechanisms of feeding (3)

Answer 6

• Filter/Suspension Feeding
• Fluid feeders
• Bulk feeding

Question 7

What is Filter/Suspension Feeding?

Answer 7

• Non-specific ingestion
• filter out what they don’t want or need.

Question 8

Filter/Suspension Feeding
of Baleen Whales

Answer 8

• use baleen plates [bristles made of keratin]
• filter, sift, sieve and trap plankton and small fish.

Question 9

Filter/Suspension Feeding of Shellfish

Answer 9

• filter microscopic organisms through gill plates

Question 10

What is fluid feeding?
examples?

Answer 10

Animals pierce and suck the fluid from animals / plants.

eg. Mosquitoes and leeches use anticoagulants– keep blood from clotting while they eat

eg. Tapeworms attach to intestinal lining to absorb nutrient-rich fluids from hosts digestive tract

Question 11

Bulk Feeding [Most animals, including humans
]

Answer 11

• Large chunks of food at a time,
• require specialized structures to assist in capturing and digesting food

Question 12

Evolution of digestion (2)

Answer 12

• Closed tube (ex: Hydra): one opening for food nad wastes. Waste through various points along the length of the organisms body.
• Open tube (ex: Humans): an opening for obtaining food and a second opening for eliminating waste.

Question 13

Types of digestion (2)

Answer 13

• Intrcellular (ex: paramecium)- Inside cell
• Extracellular (ex: Mammals, fungi)- Outside cell

Question 14

Overview of Digestion (6)

Answer 14

1. Ingestion 2. Digestion
2. Absorption 4. Transport
3. Metabolism 6. Excretion

Question 15

What is Ingestion

Answer 15

bring food and drink into the body

Question 16

What is digestion? Egestion/elimination?

Answer 16

• Physical and chemical breakdown of food and drink into small molecules

→ Expelling unusable parts of food ex. feces

Question 17

What is Absorption?

Answer 17

Nutrients from internal cavities into the bloodstream

Question 18

What is Transport?

Answer 18

Getting nutrients to the cells, where needed

Question 19

What is Metabolism?

Answer 19

Chemical processes of using nutrients and oxygen

Question 20

What is Excretion?

Answer 20

Expelling waste products of metabolism