Please enable JavaScript.
Coggle requires JavaScript to display documents.
identifying living things (bacteria: neither animal nor plant (how are…
identifying living things
keys can be used to identify particular organism or group of organisms
at each step, we ask a question and have to answer yes or no
divided into 2 smaller groups at each step
called a dichotomous key
are easy to use because have to answer yes or no
key could be made in different ways by using different characteristics of animals and plants
pg 113
how do we identify vertebrates
pg 114
if we are given some characteristics of it, we are able to characterise it
how do we identify plants?
pg 114
how do we construct simple dichotomous key?
use differences among things
the things may have some similarities. but we cannot use these similarities to make a key
pg 115
bacteria: neither animal nor plant
one such group of living things that is neither animal nor plant is bacteria
they are very small: they can also seen with microscope
there is large diversity of bacteria
found everywhere: in air, soil, water, inside our bodies and on skin
different kinds of bacteria have different shapes: some are spherical, rod-like, while others have spiral shape: one way to classify bacteria
can be classified according to effects they have on human life.
some bacteria can be used to make products that improve human life, while others cause diseases
how are some bacteria helpful?
health
there are over 500 to 1000 types of bacteria found in digestive system
help in digestion of food. some keep us healthy by preventing disease-causing bacteria from attaching themselves to our intestines. some bacteria are also responsible for production of certain vitamins in body
decomposition
bacteria in soil help break down dead organisms into simpler substances that plants absorb and use for growth
food production
bacteria work produce many foods we eat. eg, bacteria that cause milk to turn sour are used to produce cheese and yoghurt. vinegar is produced by action of bacteria on alchohol
how are bacteria harmful?
some cause diseases including cholera, tuberculosis, tetanus and sexually transmitted infections
can cause food to decay or turn 'bad'
some get onto food where they release harmful substances that cause food poisoning
pg 119