Transcript Biology Revision PowerPoint


Kingdom (Animalia, Plantae, Fungi, Prokaryotae
(bacteria), Protoctista)
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Phylum

Class

Order

Family – always ends ‘ae’ or ‘ea’
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Genus – Italicised, capital letter
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Species – Italicised, lower case letter,
Linnaeus
Classification
Kingdom
Phylum
Class
Order
Family
Genus
species
Mnemonic
Largest
Smallest
Knowledge
Plus
Careful
Observation
Frequently
Guarantees
success
 Vertebrates
= having a backbone
or spinal column. (eg cat, human,
fish, frog) phylum chordata.
 Invertebrates
= Lacking a
backbone or spinal column. (eg
slug, starfish, insects)
Name
Main characteristics
Fish
Have wet scales and gills, lay
eggs in water.
Amphibians
Have smooth, moist, permeable
skin. Adults have lungs. They
lay eggs in water.
Reptiles
Have dry, scaly skin. Have lungs
They lay leathery shelled eggs.
Mammals
Have hair on their body and
mammary glands that produce
milk. Have lungs. They give birth
to live young.
Birds
Have feathers and a beak. Have
lungs. They lay hard shelled
eggs.
Absorbing oxygen?
 Fish and young amphibians = gills
 Mammals, birds, reptiles and adult amphibians = lungs
Reproduction?
 Internal fertilisation – sperm meets egg inside the body = mammals
 External fertilisation – female lays eggs then male releases sperm onto
them = fish, amphibians
Maintaining Body temperature?
 Homeotherms – keep body temperature constant by releasing heat to
their surroundings = mammals
 Poikilotherms – body temperature changes with surroundings =
reptiles
Species are organisms that are capable of
interbreeding to produce fertile offspring.
Have Binomial Names eg Homo sapiens
Felis catus
Exceptions
1. Hybrids (cross between 2 different species) eg
horse and donkey = mule
2. Ring Species Sometimes there are a chain of
neighbours that can all breed with their
neighbour but the ones at either end can’t.
These are called a ring species.
Differences within a species.
– Caused by the environment eg. hair
 Environmental
length, sun tan
– inherited eg. natural hair colour, eye colour,
certain diseases such as cystic fibrosis
 Genetic
variation – range from low to high eg
height, weight
 Continuous
 Discontinuous
colour
variation – distinct categories eg eye
Height
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An allele is an
alternative form of a
gene (one member of
a pair).
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Organisms have two
alleles for each
characteristic eg hair
colour, eye colour.
Gamete
(egg)
23
chromosom
es
23
chrom
osom
es
23 pairs of
chromosomes
(one from each
gamete)
Gamete
(Sperm)
Normal
Body Cell
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Capital letters show
dominant alleles
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Lower case letters show
recessive alleles
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The letters in the boxes
represent the genotype
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The characteristic you see is
called the phenotype eg red
flowers
•The dominant allele for
brown eyes is B.
•The recessive allele for blue
eyes is b.
A mother with brown eyes
and a genotype Bb
reproduces with a father with
brown eyes and genotype
Bb.
What chance does the next
generation have of having:
Brown eyes?
Blue eyes?
B
b
B
BB
(brown)
Bb
(Brown)
b
Bb
(Brown)
bb
(blue)
Ratio =
3 brown:1 blue
Probability =
3 in 4 brown
1 in 4 blue
Percentage chance =
75% brown
25% blue
Inherited disease caused by 2 recessive alleles (cc).
Dominant allele (C) causes person to be CC – healthy or
Cc - carrier.
Symptoms
thick sticky mucus on lungs
coughing
bacterial chest infections
Breathlessness
What chance of having cystic fibrosis from two carrier
(Cc) parents?
1a. Which people
have the
disease?
b. What alleles do
they have?
Dominant – C
Recessive - c
2. Al and Bev have
the same alleles –
what are they?
Al
Izzie
3a. Izzie could have
2 combinations of
alleles – what
could they be.
b. Why can we not
tell from this
diagram which
ones they are?
Bev
Jack Deb
Fred
Helen
Gary
Emma
Inherited disease caused by two recessive alleles
(ss). Healthy = SS Carrier = Ss
Red blood cells become mis shaped so can’t carry
as much oxygen.
Symptoms
Tiredness
Shortness of breath
Pale skin
Fainting
Homeostasis is maintaining a stable internal
environment inside the body.
Vasoconstriction
When it is cold, capillaries under
the skin contract (get narrower) to
reduce blood flow to the skin.
Vasodilation
When it is warm, capillaries under
the skin dilate (get wider) to
increase flood flow near the skin.
What is the
sense?
What stimulus is
detected by the
receptors?
Skin
Touch
Pressure, pain,
heat, cold
Eye
Sight
Light
Nose
Smell
Chemicals in air
Ear
Hearing
Sound waves
Tongue
Taste
Chemicals in food
Sense Organ
Brain
Spinal Cord
The main part is called the central nervous system
(CNS). It consists of the brain and spinal cord.
The nervous system carries electrical impulses to and
from all parts of your body.
Myelin Sheath
Stimulus eg
smelling food
Impulse starts at
r_________
(n____)
Impulse passed
along s_________
neurone
Impulse travels to
C________
N_________
S__________
Response – walk
to food shop
E_________
(muscle) receives
impulse to react
Impulse passed
along m______
neurone
Stimulus –
stepping on a pin
Impulse starts at
r_________
Impulse passed
along s_________
neurone
Impulse passed
along r______
neurone
Response – lift
foot away from pin
E_________
receives impulse
to react
Impulse passed
along m______
neurone
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Hormones are c__________ messengers.
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They are released by glands called
e_________ glands that are found in organs.
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Hormones travel in the b______ p______.
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The organ affected by the hormone released is
called the t_____ organ. This is not always the
same as the organ that releases the hormone.
Type 1
Type 2
Onset
Usually born
with
Acquired in later life
Problem?
Pancreas produce insulin but
cells don’t respond to it
Cause
Pancreas does
not produce
insulin
Genetic
Treatment
Inject insulin
•May need to inject insulin
•May be able to have tablets
•May control with low sugar
diet and regular exercise.
Obesity, high fat/sugar diet,
lack of exercise, old age
Plant Hormones
Plant stems always grow towards the light.
This is called positive phototropism.
It is controlled by a hormone called auxin and
sunlight.
Plant roots always grow downwards.
This is called positive geotropism.
It is also controlled by the hormone auxin and
gravity.
Selective Weedkillers
Auxin sprayed on crops. Makes broad leaf plants (like weeds)
grow out of control and die. Doesn’t affect the crop.
Fruit Ripening
Hormones used to speed up ripening so fruit can be picked in
one go, or to ripen fruit so it is ready to eat. Eg ethylene on
bananas shipped in from abroad.
Seedless Fruit
Spray plants with hormones to make fruit grow but not the
seeds.
Rooting Powder
Cut plant stems dipped into hormones to encourage roots to
grow.
Addictive - stimulate receptors in the brain. Need more and more to
get the same effect.
Dependent – need the drug to get by each day.
Hallucinogens – distort perception of sight/soun/smell/taste eg
magic mushrooms, LSD
Narcotics – make you sleepy
Stimulants – speed up nervous system eg caffeine, nicotine,
cocaine
Depressants – slow down nervous system eg alcohol, cannabis
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Tar – sticky, sticks to inside of lungs. Carcinogen
(causes cancer)
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Nicotine – the drug that makes cigarettes addictive
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Carbon monoxide (CO) – binds with haemoglobin
in red blood cells instead of oxygen. Reduces the
amount of oxygen the blood can carry.
Short term effects
 Slow down activity of brain and nervous system
(depressant)
 Slows reaction times – blurred vision, slurring,
possible unconsciousness/death
 Reduces inhibitions
Long Term Effects
 Liver cirrhosis – irreversible damage can lead to
liver failure/death
 Brain damage/blood clots in the brain
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Donor (may be dead/alive for certain organs eg 1
kidney)
Provides organ for person with organ failure.
Heart, lungs, kidney, liver, corneas,
Whether to give or not (an ethical decision)
Age?
Obesity?
Misuse of drugs?
Close match?
How ill is the recipient?
Microorganisms (bacteria fungi and viruses)
that cause disease.
By damaging cells or releasing toxins.
If the microorganism doesn’t make you ill it
is not a pathogen eg penicillium mould on
bread.
A microorganism that can cause harm or disease is
called a pathogen.
Pathogen
Not a pathogen
Direct Contact
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

Touching – athlete’s foot (fungus)
Kissing – herpes virus
Sexual contact – HIV (virus)
Sneezing – Influenza (virus)
Indirect Contact
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Vehicle Borne (physical things)
o In water – Cholera (bacteria)
o In food – Salmonella (bacteria)
o On objects – Tetanus (bacteria)
Vector Borne (via animals)
◦ Dog bite – rabies
◦ Anopheles Mosquito – malaria (protazoan)
◦ Housefly – Dysentary (bacteria)
Chemical Barriers
Physical Barriers
Antiseptics – chemicals that have antibacterial
properties. Often extracted from plants.
•
Toxins produced by fungi that kill bacteria.
•
Eg penicillin, amoxycillin, streptomycin
Misuse:
 Not completing course
 Taking for viral infections
LEADS TO BACTERIAL RESISTANCE
Food Chains
•Only shows one organism
at each stage.
•Start with a producer.
•If the organism eats
something it is a predator.
•Things eaten by predators
are called pray.
•Changes in numbers of
organisms in the chain will
affect the whole food chain.
Food webs
•More than one
predator may eat the
same pray.
•More than one type of
pray may be eaten by
the same predator.
•What would happen to
the numbers of rabbits
if the number of snails
decreased?
Pyramid of biomass
Pyramid of numbers
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Parasitism – two organisms live together
with one feeding off the other.
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The organism the parasite feeds off is
called the host. eg. headlice and fleas
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Mutualism – two organisms live together
and both benefit eg tubeworms and
bacteria, legumes (bean plants) and
nitrogen fixing bacteria.
Causes
 Population
growth – more resources used
fossil fuels – release CO2 and SO2
into air – fossil fuels – global warming
 Burning
uses fertilisers – washi into lakes
and rivers – causes EUTROPHICATION
 Farming
Fertilisers (nitrate, phosphate, potassium) wash into rivers
and streams.
Cause rapid, excessive growth of algae.
Algal bloom blocks light from underwater plants for
photosynthesis so plants die.
Decomposing bacteria decay plants and use OXYGEN for
repiration.
Lack of oxygen causes fish and other organisms to die.
Organisms that are sensitive to pollution can be used to
indicate the presence of pollution.
Blackspot Fungus – killed by sulphur dioxide
Lichens (fungus and algae mutualistic relationship) – certain
species indicate high/low levels of sulphur dioxide and
nitrogen oxides
Stonefly Larvae and Freshwater shrimps need lots of O2
Bloodworms and Sludgeworms – little O2
The CARBON CYCLE
involves four very
important steps
1)
2)
3)
4)
PHOTOSYNTHESIS
RESPIRATION
DECAY
BURNING FOSSIL FUELS
fixing bacteria – atmospheric nitrogen
to nitrates
 Nitrogen
 Decomposing
Bacteria - animal/plant matter to
urea and ammonia
 Denitrifying
Bacteria - ammonia to atmospheric
nitrogen

Animals eat plants and take in nitrogen
compounds eg proteins