Homeostasis & Integration

Question 0

Evolutionary (ultimate) explanation of biological phenomena

Answer 0

The answer to “how did it get to be this way?”. Recognises that biological features are the result of variation or natural selection.

Eg: Wings of birds and wings of insects. Similar structure/function but came about independently with no common ancestor.

Question 1

Mechanistic (proximate) Explanation of biological phenomena

Answer 1

The answer to “how does it work?”. Emphasises the mechanism or composition of a function or structure. The traditional core of physiological or medical sciences.

Eg: Shivering. A homeostatic function where temperature sensitive nerve cells send signals to the hypothalamus which responds with feedback initiating shivering to raise body temperature.

Question 2

Explain “Homologous”

Answer 2

Traits between two different organisms that are related by common ancestry. For example: birds wings and human arms. Both have same bony components.

Question 3

Explain “Analogous”

Answer 3

Analogous traits are those with similar structures and/or functions but have no common ancestry. For example: bird and insect wings.

Question 4

What is Biological Adaptation

Answer 4

Traits or adaptations that have been developed through random variation and natural selection. They include pelage colouration, or visual acuity. There are two explanations:

1. Mechanistic or proximate
2. Evolutionary or ultimate

Question 5

What is the Teleological Approach?

Answer 5

Phenomena that occur in organisms are explained in terms of their purpose.

Question 6

Explain Vestigial

Answer 6

A structure that has no function. Has not been eliminated by selection.

Question 7

Explain Cost-benefit Trade-off

Answer 7

Adaptations have costs that negatively impact other adaptations. The most basic trade-off is energy.

Question 8

Adaptations

Answer 8

Beneficial features that enhance an organism and its species chances of survival.

Question 9

Name the 5 steps in the hypothetico-deductive scientific method.

Answer 9

1. Ask a question about process in nature.
2. Propose a hypothesis to explain the process and a few alternatives
3. Design an experiment to test the hypotheses
4. Carry out the experiment
5. Use the experimental data to formulate new hypotheses where necessary

Question 10

What are the four properties of life?

Answer 10

1 Self-organisation eg: using external resources to create and maintain the cell.

2. Self-regulation eg: maintain self-integrity in the face of disturbances.
3. Self-support and movement eg: structures that support the cell, allow the cell to move or materials inside the cell to move.
4. Self-replication eg: reproducing to carry on the species and repair cell damage.

Question 11

What are the four major tissue types?

Answer 11

1. Epithelial tissue (protect, secrete, absorb) eg: glands, lining tissue.
2. Connective tissue (connects, supports, anchors) eg: tendons, blood, bone.
3. Muscular tissue (contraction and force) skeletal, cardiac, smooth muscle.
4. Nervous tissue (communication, transmission) eg: brain, spinal, epithelial linings, effector organs.

Question 12

Describe the construction of organs from tissues.

Answer 12

Organs are made up of two or more primary tissue types:
1. Epithelial lining which include exocrine and endocrine glands
2. Connective tissue
3. Muscle tissue
4. Nervous tissue
Organs are then organised into systems which perform related functions to achieve a common goal eg: digestive tract

Question 13

How does surface area change with size and why is this important?

Answer 13

Surface are changes with size in the relationship of volume to mass. Volume is related to the cube of the radius and mass is related to the square of the radius. Larger animals have a smaller surface to volume ratio than do small animals. The bigger the volume the smaller the surface area.

Question 14

What is meant by scaling?

Answer 14

Scaling is the study of the effects of size on anatomy and physiology.

Question 15

What is surface area to volume ratio?

Answer 15

Volume is related to the cube of the radius (10^3) and surface area is related to the square of the radius (10^2). The bigger the volume the smaller the surface area ratio (1000 times vs 100 times). Larger organisms have small surface-to-volume ratios.

Question 16

What are some aspects of physiological function affected by size?

Answer 16

Scaling affects skeletal mechanics: ie a bigger skeleton is needed to support a bigger mass.

A larger organism can retain heat better than a smaller organism because it has a smaller surface-area-to-volume ratio.