Biology Module 4 Flashcards
What is the definition of a population?
All the organisms of one species in a habitat
Explain Van Helmonts experiment
He decided plants gained mass by taking in water. He dried, weighed, and planted some soil. He planted a willow tree that weighed 2.2kg and added rainwater when it was dry. 5 years later he removed it, it weighed 74.5kg. The soil mass had barely changed. He concluded that as the soil hadn’t gained much mass from another source, the water.
What makes up a community?
Populations of different species in a habitat
What is the equation used to estimate population size?
Population size= number in first sample x number in second sample divided by number in second sample previously marked.
What is an ecosystem?
All the organisms living in a particular area, as well as the non-living conditions EG temperature etc
What is the only thing needed in an Eco system?
An energy source, usually the sun
What are transepts used for?
To investigate the distribution of organisms
What do kite diagrams show?
The abundance and distribution of organisms
What are abiotic factors?
All the non-living, physical factors in an environment, EG light, temperature, water
Why is the distribution of organisms affected by the abiotic factors?
Organisms are adapted to live in certain physical conditions, and many organisms can only survive in the conditions they’re adapted to ed mosquitoes are adapted to live in warm climates so can’t survive cold
What is zonation?
The gradual change in the distribution of species across a habitat
What is biodiversity?
A measure of the variety of life in an area
What does biodiversity include?
Amount of variation between individuals of the same species in an area, the number of different species in an area and the number of different habitats in an area
Why do natural ecosystems have a higher biodiversity than artificial ones?
Because they maintain themselves without any major interference from humans
What is the equation for photosynthesis?
6co2+6h2o>c6h12o6+6o2
Where does photosynthesis take place?
In chloroplasts in plant cells
How do plants use the glucose they make?
Respiration, stored in seeds, making proteins, making cell walls, stored as starch
What did Aristotle conclude about plant growth?
That the only thing touching plants was soil,so plants must grow and gain mass by taking in minerals from the soil
Describe one of priestleys experiments
He put a burning candle in a sealed container, and observed that the flame went out after a short while, and couldn’t be relit. He then placed a burning candle and a living plant in the container. The flame went out after a while, but could be relit after a few weeks.
Describe another of priestleys experiments
He filled a sealed container with exhaled air, he put a mouse in the container and observed that it only survived a few seconds. He filled a other sealed container with exhaled air, and put a living plant in the container and waited a few days. He then put a mouse in the container, which survived for a few minutes.
What did Priestley conclude about the candle experiment?
That the candle must use up something in the container, which made the flame go out, and the living plant must restore the air so the candle could burn again.
What did Priestley conclude about the mouse experiment?
That the mouse couldn’t survive long in exhaled air because breathing had taken something our of the air. He decided that the living plant restored the air, which allowed the mouse to survive for longer.
What was priestleys conclusion of both experiments?
That plants restore something to the air that burning and breathing take out. Today we know this substance to be oxygen, as a product of photosynthesis.
What are the 3 limiting factors that control the rate of photosynthesis?
Not enough light slows down the rate of photosynthesis, too little carbon dioxide also slows it down and the temperature has to be just right.
What is diffusion?
The net movement of particles from an area of higher concentration to an area of lower concentration.
What diffuses through cell membranes?
Simple sugars, water or ions
What does the rate of diffusion depend on?
Distance, concentration difference and surface area
Give the word equation for respiration
Glucose + oxygen > carbon dioxide + water
When does photosynthesis happen and why?
It happens during the day because there’s light available
What do plants do at night?
Plants only respire as there’s no light for photosynthesis, so they take in oxygen and release carbon dioxide.
Give 2 ways plants are adapted for diffusion
Broad- large surface area for gases to diffuse
Thin- carbon dioxide and water vapour only have to diffuse a short distance
What is the purpose of the stomata?
To let gases like co2 and O2 in and out.