Ch 9, 10,11 Flashcards
Define the term homeostasis?
Homeostasis is the ability of the body to maintain the condition of its internal environment to maintain stable condition
Which is more variable: your external environment or the internal environment of your cells
Your external environment is more variable as your internal environment is constant due to homeostasis
List three variables that are subject to homeostasis?
Temperature
Water
Blood Glucose
What are the two major body systems responsible for maintaining homeostasis?
The endocrine (hormonal) and nervous systems are the major systems responsible for the control and coordination of homeostasis
Distinguish between the central nervous system and the peripheral nervous system?
The brain and the spinal cord make up the Central Nervous System and all other nerve cells, in whole or part, that lie outside the central nervous system for the peripheral nervous system
Distinguish between the sensory neuron and effector neuron
Effector neurons carry impulses away from the central nervous system to muscle cells
Distinguish between axon and dendrite
Axon is extension of a nerve cell along which impulses are transmitted away from the cell
Dendrites are branched extensions of a nerve cell that transmit impulses to the cell
Distinguish between receptor and effector organs
Receptors detect specific sensory information from the external environment eg soundwaves
Effector organs respond to the stimulus from the nerve
List the major sense organs
Sight, hearing, smell, taste and touch
List the five taste sensations
Sour, salt, sweet, bitter, umami
What are the main glands involved in the endocrine system
- Hypothalamus
- Pituitary
- Thyroid
- Adrenals
- Pancreas
- Ovaries/ Testes
List the events that occur in the human body if the core temperature threatens to drop below the set point of the hypothalamus
- ‘warming up’ mechanism activates
- motor Neurons relay messages
- skeletal muscles activated; shivering generates heat
- increased heat production
- body temperature rises
Explain why evaporation of sweat is an important factor in maintaining a stable core temperature on a very hot day?
The evaporation of water requires heat that is provided by the body
Explain how behaviour of an individual can contribute to maintenance of a stable core temperature
The way a person reacts to different weather conditions and levels of physical activity can contribute to maintenance of a stable core temperature
What is the source of body heat for an ectotherm
Ectotherms expose as much of their body as they can to the sun
Give one structural and one behavioural adaptation of a frog that enables it to survive in a cold environment
Some frogs and toads live underground during the winter to avoid freezing temperatures
Many desert mammals have countercurrent systems leading to the brain? What is the purpose of such a system and it’s structure?
The purpose of a countercurrent system is to warm blood.
How do hibernating animals survive their drop in body temperature
When mammals hibernate, their heartbeat slows, breathing rate drops, metabolism drops and body temperature drops. This can last between 3 and 7 days at a time
Briefly explain how cells of plants living in subzero conditions survive the formation of ice crystals?
Because ice has formed, the concentration of water inside the living cells is higher than the concentration outside and so water moves out of cells. The movement of water out of cells increases the ion concentration inside the cells and so lowers their freezing point even further. The more concentrated cytosol works as an antifreeze
Explain two features of plants that enables them to reduce heat uptake
Leaf shape- the larger ratio of edge length to surface area, the faster the leaf will be cooled
Leaf fall- leaf fall during the dry season decreases the surface area through which heat may be gained and water vapour lost
Explain the dangers of evaporative cooling for a plant
During transpiration, excessive water loss in plants can cause death
Where are the vasopressin and renin formed and what is the role of each in water balance
- Vasopressin is formed in the hypothalamus of the brain. If there is a drop in the blood, vasopressin gets released into the bloodstream via the posterior pituitary gland. It is transported to the kidney where it increases the amount of water that gets absorbed.
- Renin is found in the kidneys, when dehydration occurs. The function of renin is to restore normal blood pressure, thereby increasing filtration rates of water and salutes in the kidney tubules so that filtration proceeds in proper balance
Explain how a variation in water balance causes a variation in blood pressure
As water content varies, blood pressure also varies. Increased water content raises blood pressure, decreased water content lowers blood pressure. The process of osmoregulation and blood pressure control interact
Why is water loss from a plant inevitable?
When stomata are open, gases, including water vapour, are able to diffuse in or out of the leaf
List the regions and cells through which water passes as it moves from the soil into a plant, to the leaves at to the atmosphere?
Water enter where the root hairs grow, it moves across the cortex and endodermis before it reaches the xylem. From the xylem into the leaf, water moves from the xylem into surrounding mesophyll cells. The water vapour moves out of leaves into the stomata
What causes the stomatal pores to open?
When guard cells become filled with water (become turgid), it causes the stomata pores to open
Give two special structures that reduce water loss from a plant
The cuticle- which is the waterproof outer layer of the leaf, reduces water loss
The pores of the stomata can vary how open they are
Explain how atmospheric humidity influences water loss from a plant
Water vapour moves out of stomatal pores in a leaf much more quickly when the leaf is surrounded by dry air than when the leaf is surrounded by humid air
List the types of innate behaviours
COmmunication, Reproductive, Competitive
How would you classify a play dead behaviour
An communication behavior which is used to survive
Mother cats sometimes give their kittens live mice to play with. Why might such play be an important behavior for the kitten?
It is a learned behavior as it teaches the kitten association with the mice at a young age
What are the three kinds of learned behavior?
Conditioning, Habituation and Imprinting
How does a plant that is positively phototropic respond to light?
When the movement of a plant is towards the light is known as positive phototropism
How does a plant that is negatively geotropic respond to gravity?
Shoots show negative geotropism
Name two activities of plants that show a circadian rythm
Nastic Movement- Sensitive droop suddenly in response to touch
Solar Tracking - Leaves and flowers of plants move so they are parallel or perpendicular to the sun
How would you classify a plant that flowers after being exposed to light for 14 hours followed by 10 hours dark
it is a long day plant
Define the term habitat?
The location or place where an organism lives at any given time
List the three different kinds of habitat?
Terrestrial ( eg- deserts, grasslands etc)
Aquatic ( freshwater, marine,)
Microhabitat
Identify of using satellite habitats In monitoring habitats
Satellite technology is used to monitor vegetation in habitats that cover large areas
Identify three different animals whose movements in their habitats have been monitored for satellite tracking>
Tigers, Lions and Sharks
Whats a PAT Tag?
Pat tags are tags that are programmed to collect data every few minutes over given period of time
Two species of mammal living in the same habitat both eat insects. Based on this information alone, can it be concluded that the mammals have identical feeding niches?
Yes, as long as they are catching them in the same area they have identical feeding niches
List three different feeding niches in a freshwater lake habitat?
Vegetations at the bottom of the lake, fish, small plants and animals
Would it be reasonable to predict that several species living naturally in a natural community would have a high degree of niche overlap
No, as a high degree of niche overlap would lead to the elimination of one or two species
How would you be able to measure the relative humidity of the air
You would measure with a hygrometer
What instrument would you use to measure the salinity of the water
Conductivity Meter
Define Habitat
Part of an ecosystem in which an organism lives, feeds and reproduces
Define Range
Geographic area enclosing all the habitats where a given species lives; sometimes referred to as distribution
Define Niche
way of life of organisms in an ecosystem; roles of species in a community
Define Migration
Refers to the predictable movements of organisms over large distances, which may occur once in the lifetime of an organism (eg eels) or yearly (eg muttonbirds)
Define Population
Members of one species living in a specific habitat at a particular time
Define Environment
the surroundings or conditions in which a person, animal or plant lives or operates