Module 3

Question 1

Define anatomy and physiology

Answer 1

Anatomy is the biological form of an organism, while physiology is the biological functions that an organism performs. These are the comparative study of animals that reveal the form and functions that are closely related.

Question 2

Explain how the size and complexity of an animal’s body influences the need for specialised branched or folded structures to facilitate exchange of materials such as nutrients, waste products, and gases across the cell membranes.

Answer 2

Size and shape effect the way an animal interacts with its environment, with the body plan of an animal being programmed by the genome (which itself is the product of millions of years of evolution).

• as animals increase in size, thicker skeletons are required for support
• properties of water limit possible shapes for fast swimming animals
• physical laws govern strength, diffusion, movement, and heat exchange

Question 3

Name five fundamental challenges that are common to all animals.

Answer 3

1. The need to feed
2. Circulation and gas exchange
3. Combating pathogens
4. Osmoregulation and excretion
5. Reproduction

Question 4

What are the gastrovascular cavity and Alimentary canal?

Answer 4

The gastrovascular cavity has only one opening that serves as both a mouth and an anus, where food is digested and secreted.
The alimentary canal is the pathway by which the food consumed passes from mouth to anus, for further process of digestion. (digestive tract)

Question 5

Explain the difference between intracellular and extracellular digestion.

Answer 5

In intracellular digestion, food particles are engulfed by phagocytosis and liquids by pinocytosis. A few animals, such as sponges, digest all their food by intercellular digestion.

Extracellular digestion is the breakdown of food particles outside of cells. It occurs in compartments that are continuous with the outside of the animal’s body. Animals with simple body plans have a gastrovascular cavity that functions in both digestion and distribution of nutrients

Question 6

Define gas exchange and give examples of different types of respiratory surfaces that are found in different animals.

Answer 6

Gas exchange is the process of taking in oxygen from the environment and releasing carbon dioxide. Different animals have evolved various respiratory surfaces to facilitate this exchange:

Lungs: Found in terrestrial vertebrates like mammals, birds, and some reptiles.
Gills: Present in aquatic animals such as fish and some amphibians.
Tracheal system: Seen in insects and certain other arthropods.
Moist skin: Found in some amphibians and invertebrates like earthworms.

Question 7

Distinguish between innate and adaptive immunity and identify which broad taxa of animals have which type(s) of immune responses.

Answer 7

Innate immunity = a rapid response - using a small set of receptors (all animals)

Adaptive immunity = slower response – using a vast array of receptors (vertebrates only)

Question 8

Define the terms osmoregulation and excretion.

Answer 8

Osmoregulation is the maintenance of a fluid balance within narrow limits.
Excretion is the process of which an organism eliminates nitrogenous waste from their body.

Question 9

List the four key steps that excretory systems undertake in the process of regulating solute movement between internal fluids and the external environment.

Answer 9

1. Filtration
2. Reabsorption
3. Secretion
4. Excretion

Question 10

Explain the fundamental differences between asexual and sexual reproduction.

Answer 10

Asexual reproduction is when new individuals are generated without the fusion of egg and sperm, typically relying of mitotic cell division.
Sexual reproduction is the fusion of haploid gametes that form a diploid cell (zygote). The animal that develops from a zygote can in turn give rise to gametes by meiosis.

Question 11

List the levels of organisation within an animal.

Answer 11

1. Tissues
2. Organs
3. Organ systems

Tissues make up organs, which together make up organ systems.

Question 12

List the four main types of animal tissues and what they do and where in the body you would find them

Answer 12

• Epithelial
• Connective
• Muscle
• Nervous

Question 13

Provide three different examples of respiratory surfaces found in animals.

Answer 13

Tracheal system (insects), gills (fish), and lungs (mammals).

Question 14

Which type of immunity do all animals have?

Answer 14

Innate immunity, which is a rapid response that uses a small set of receptors.

Question 15

Which type of immunity is unique to the vertebrates?

Answer 15

Adaptive immunity, which is a slow response that uses a variety of receptors.

Question 16

In what type of environment would you expect to find an osmoconformer?

Answer 16

Osmoconformers are marine animals whose internal osmolarity is the same as that of its environment

Question 17

In what type of environment would you expect to find an animal that excretes nitrogenous waste as ammonia?

Answer 17

In an aqueous environment

Question 18

Provide examples of types of animals that typically excrete nitrogenous waste as uric acid

Answer 18

Birds, reptiles and insects.
Animals that typically excrete nitrogenous waste as uric acid are often those that need to conserve water due to their habitats or lifestyles.

Question 19

List the four key steps performed by excretory systems.

Answer 19

Filtration, reabsorption, secretion and excretion.

Question 20

Name the type of excretory system found in each of the following: a flatworm, an earthworm, and insect, and a mammal.

Answer 20

Flatworms→ Flame cells (it is a hollow specialized cell that helps in the excretion of simple animals)
Earthworms→ Nephridium (these are coiled tubules found in most invertebrates. It is found arranged segmentally in earthworms)
Insect→ Malpighian tubules (these are tubular excretory organs, the junction of which directly open into the mid and hindgut.)
Mammals → The main excretory system in animals is the urinary system. The urinary system is composed of the kidneys, in which urine is produced, ureters, urinary bladder, and the urethra.

Question 21

What are the common names for the female and the male gamete?

Answer 21

Female = egg
Male = sperm

Question 22

What are some costs and benefits of asexual and sexual reproduction?

Answer 22

Asexual reproduction:

Costs - poor immunity if targeted disease attacks specific genes - as they all have the same copies of DNA

Benefits - Cheap/efficient on energy, fast production with large amounts of offspring

Sexual reproduction:

Costs - High amounts of energy required, slow production with few offspring

Benefits - Creates variation

Question 23

Explain what is meant by the ‘twofold cost’ of sex.

Answer 23

Under a two‐fold cost of sex (c = 2), asexual females can produce twice as many childbearing offspring (females) as sexual females.

Question 24

Name the four main types of animal tissues

Answer 24

• Epithelial
• Connective
• Muscle
• Nervous

Question 25

What are the four classes of essential nutrients that animals need from their diet?

Answer 25

• Essential amino acids
• Essential fatty acids
• Vitamins
• Minerals

Question 26

What is ingestion?

Answer 26

the process of taking food, drink, or another substance into the body by swallowing or absorbing it.

Question 27

What is digestion? And what are the two types of digestion?

Answer 27

Digestion is the process by which food is converted into substances that can be absorbed and assimilated by a living organism.

In intracellular digestion, food particles are engulfed by phagocytosis and liquids by pinocytosis. A few animals, such as sponges, digest all their food by intercellular digestion.

Extracellular digestion is the breakdown of food particles outside of cells. It occurs in compartments that are continuous with the outside of the animal’s body. Animals with simple body plans have a gastrovascular cavity that functions in both digestion and distribution of nutrients

Question 28

What are the four main feeding mechanisms of animals?

Answer 28

1. Filter feeding- common in aquatic animals
2. Substrate feeding - when they live on their food source
3. Fluid feeding - suck nutrient-rich fluid from a living host
4. Bulk feeding - consuming large pieces of food.