Transcript Revision powerpoint for B1

Natural selection
Drugs and clinical
trials
Control and coordination
B1 topics
Diet and health
Adaptation
Cloning and genetic
engineering
Immunity
Competition for
resources
Energy in food
chains
Reflex actions
Responding to
change
Homeostasis
B1.2 Coordination and Control
Fertility
Hormones and
plant growth
Hormones and
menstrual cycle
Responding to change
• The nervous system
carries electrical
impulses along
neurones
Stimulus
Change in the
environment
Receptor
E.g. Eyes, skins, found in
sense organs
Sensory neurone
CNS
Brain and spinal cordcoordinates response
Motor neurone
Effector
Muscles (contract) or
glands (secrete)
Reflex actions-
Fast, automatic, protective
Synapses
Gap between 2 neurones
Electrical impulse changed into a chemical messenger
Chemical diffuses across the gap to the next neurone
Hormones and fertility
Produced
by Target
Effect
•Hormone
Glands secrete
hormones
whichorgan
are then carried
around in the blood
Menstrual cycle
FSH
Pituitary
Ovary- developing
Stimulates the
egg to
Contraception
Brought about by hormones made and released
gland
follicle
develop
Inhibits production
by pituitary gland and ovaries
of FSH so eggs
Hormones:
don't mature in the
FSH
Oestrogen
Ovary
1) Uterus
1) Increase the uterus
ovaries
-causes eggs to mature
lining
-Stimulates the ovary to produce oestrogen
2) Pituitary gland
2) Stop FSH production
Fertility treatments
Oestrogen
LH
Pituitary
egg
Ovulationeggeggs
released
FSH used
to stimulate
to mature
-Causes
the lining of
the uterus toOvarydevelop
gland
fromoestrogen
ovary production
and trigger
-Inhibits FSH production
IVF - eggs collected and fertilised in the
-Stimulates the release of the mature egg
lab then implanted
Others: progesterone and LH
Progesterone
Ovary1) Uterus
1) Maintain the uterus
28 days: womb liningyellow
thickens,
Eggs
body
lining
Advantages
fewer
children
released from ovary after
14 days
(empty
egg - 2) Pituitary gland
2) Stop -FSH
production
(cost), women freedom
ovulation, If not fertilised,
the womb
follicle)
lining and egg come out as a period
Disadvantages - expensive,
multiple births, embryo use
Hormones and fertility
•
Hormones
•
Chemical messengers
•
Produced in glands
•
Travel in glands
•
Act on target organs or cells
Hormones and fertility
Produced
by Target
Effect
•Hormone
Glands secrete
hormones
whichorgan
are then carried
around in the blood
Menstrual cycle
FSH
Pituitary
Ovary- developing
Stimulates the
egg to
Contraception
Brought about by hormones made and released
gland
follicle
develop
Inhibits production
by pituitary gland and ovaries
of FSH so eggs
Hormones:
don't mature in the
FSH
Oestrogen
Ovary
1) Uterus
1) Increase the uterus
ovaries
-causes eggs to mature
lining
-Stimulates the ovary to produce oestrogen
2) Pituitary gland
2) Stop FSH production
Fertility treatments
Oestrogen
LH
Pituitary
egg
Ovulationeggeggs
released
FSH used
to stimulate
to mature
-Causes
the lining of
the uterus toOvarydevelop
gland
fromoestrogen
ovary production
and trigger
-Inhibits FSH production
IVF - eggs collected and fertilised in the
-Stimulates the release of the mature egg
lab then implanted
Others: progesterone and LH
Progesterone
Ovary1) Uterus
1) Maintain the uterus
28 days: womb liningyellow
thickens,
Eggs
body
lining
Advantages
fewer
children
released from ovary after
14 days
(empty
egg - 2) Pituitary gland
2) Stop -FSH
production
(cost), women freedom
ovulation, If not fertilised,
the womb
follicle)
lining and egg come out as a period
Disadvantages - expensive,
multiple births, embryo use
Hormones and plant growth
• Plants are sensitive, they need to grow the right way..
• Phototropism- Plant roots grow away from light and in
the direction of gravity
• Geotropism- Plant shoots grow towards light and
against the force of gravity
Controlled by the plant
hormone Auxin
The opposite
occurs in the roots
Hormones and plant growth
Auxin – hormone that controls the growth of
roots and shoot tips
1) Auxin moves to the shaded side of the
shoot tip
2) Auxin is unevenly distributed
3) This causes growth on the shaded side
4) Plant bends towards the light
Using plant hormones – used as rooting powder
or high doses as weed killers due to rapid
uncontrolled growth
The opposite
occurs in the roots
Exam Questions
Legal and illegal
drugs
Drugs in sport
Drugs
B1.3 Medicine and Drugs
Cannabis and hard
drugs
How effective are
medicines
Developing new
medicines
Developing new medicines
New drugs are tested on cells,
animal testing (e.g. Mice, rats)
and human trials
Placebo – pill that does not contain
the drug e.g. sugar pill
Double blind trial – neither doctor or
patient knows who has the real drug
Medicines
• Thalidomide–
–
–
–
Developed as a sleeping drug
Found to also cure morning sickness
Found to cause limb abnormalities
Now used to treat leprosy
• Statins– Used to lower blood cholesterol
• Painkillers– Only used to treat pain DO NOT KILL PATHOGENS
• Antibiotics– Medicines to kill bacteria DO NOT KILL VIRUSES
Drugs
Drug: alters the way the body works
Legal: coffee, cigarettes, alcohol
• Millions of people take these so health impact is much
bigger than for illegal drugs
Illegal: cocaine, ecstasy, heroin
• Affect nervous system
Withdrawal symptoms – cravings, aches, sweating etc
Addiction: dependent – cant function without the drug. More and more
is needed for same effects
Addicts may turn to crime to fund drug habits, more likely to get STDs,
mental / physical health problems
Exam questions
[6 marks]
[4 marks]
Environmental
change
Competition in
animals and plants
Adaptation for survival
Adapt and survive
Adaptation in
plants
Adaptation in
animals
Adapt and survive
Living organisms need to survive and reproduce
• Plants need: light, carbon dioxide, water, oxygen, nutrients
• Animals need: food, water, oxygen
• Microorganisms needs depend - some are light plants, some
like animals and some need no oxygen or light
Extremophiles – organisms adapted to extreme environments.
e.g. Bacteria can live at temperatures as low as -15 or up to 80C as their enzymes
are adapted not to denature.
REMEMBER S->E->A
STATE- Camels humps contain a fat store
EXPLAIN- Insulates the camel
ADVANTAGE- To keep warm during the cold nights
Extremophiles – organisms adapted to extreme environments.
e.g. Bacteria can live at temperatures as low as -15 or up to 80C as their enzymes
are adapted not to denature.
Adaptation in animals
Surface area: volume ratio
• Mammals in a cool climate grow to a large size (e.g. Whales)
to keep their ratio as small as possible to maintain body heat
Cold Climates:
 Small surface area e.g.
Ears
 Insulation – blubber
(thick layer of fat under
skin), fur coat
 Fat layer also provides
a food supply during
winter
Dry climates
 Deserts may be hot in day and freezing at night.
 Lack of water
 Often active at night rather than day
Can’t sweat or will lose water
 small – large surface area:volume to lose heat
through skin
Big ears- lose heat
Thin fur, little body fat
Camouflage : Important in predators and prey
Dependent on environment (arctic hares brown in summer and white in winter)
Adaptation in plants
In dry
climates:
– very wide
root systems
– store water
in leaves,
stems or roots
Surface area:volume ratio
Curled leaves – traps layer
of moist air, reduces
surface area
Thick cuticle – stops
evaporation
Or.. Broad leaves – large
surface area to collect
dew (water)
Environmental change
• Organisms can indicate climate change
• Lichens are sensitive to Sulfur dioxide
• Rat tailed maggots are found in polluted water
Changing birds of Britain
Bird habitats and migration affected
Dartford warblers are more
common due to increased
temperatures, but less common in
Spain where it is now too warm
Bees
Disease (CCD) affecting honey bees
Bees are important for pollination of
plants – apples, raspberries,
cucumbers etc
Cause unknown – pesticides? Climate?
Exam questions:
[6 marks]
Decay processes
Carbon cycle
B1.5 Energy in biomass
Recycling organic
waste
Pyramids of
biomass
Energy transfers
Pyramids of biomass
• Biomass is the amount of living thing
available to the next level in a food chain
– the mass of material in living
organisms
• It is the total mass without the mass of
water (dry mass in grams)
• Pyramids of biomass show how much
energy is available at levels in a food
chain
Energy transfers
Much of the energy lost in:
•
Movement (muscles
contracting)
•
Heat
•
Keeping a constant body
temperature (energy
needed to keep warm or
cool down)
•
Waste (herbivores can’t
digest all they eat,
excess protein passed
out as urea)
1110 KJ in
heat loss
3060 KJ
in food
1797 KJ in urine
and faeces
Decay processes
Detritus feeders (e.g. Maggots, worms)
start the process by eating dead
animals and producing waste material
Decomposers (microorganisms) digest
everything, using some of the nutrients
to grow and reproduce
They produce waste products – CO2,
water and nutrients
This recycling means the soil contains
mineral ions plants need to grow and
cleans up dead organisms
Conditions for decay:
• Warm
– Chemical reactions in
microorganisms work faster
when warm
– Reactions slow down and stop
if too cold, enzymes denatured
if too hot
• Moist
– Easier to dissolve food,
prevents drying out
• Plenty of oxygen
– Decomposers respire, need
oxygen to release energy
Uses: sewage treatment works,
compost
Carbon cycle
The amount of carbon is fixed
• Photosynthesis: green
plants and algae remove
CO2 from the atmosphere
– passed on when plants
are eaten
Carbon dioxide + water  glucose + oxygen
•
Respiration: living
organisms use oxygen to
break down glucose CO2 is
a waste product.
Decomposers respire too
Glucose + oxygen  carbon dioxide + water
•
Combustion: fossil fuels
contain carbon , when we
burn then CO2 is produced
Fuel + oxygen  carbon dioxide + water
Recycling organic waste
• Organic waste – (e.g. Vegetable peelings) doesn’t rot
easily in landfill, it forms a liquid that can pollute
waterways and methane gas which contributes to
global warming
Making compost:
To speed up the process:
• Mixing regularly helps oxygen get in
• Warmer conditions (up to about 70C)
• Moist conditions
Methods: compost heap, black bag,
compost bin, council composting
Exam questions
[2 marks]
Genetic
engineering
Genetic and
environmental
differences
B1.6 Variation
Inheritance
Types of
reproduction
Cloning plants
Cloning animals
Inheritance
• Genetic information is in the nucleus of cells
• Inside the nucleus are chromosomes made up of DNA – humans have 46
chromosomes (23 pairs)
• Genes are a section of DNA and control enzymes and proteins made in
your body
• Genes are passed on to you in the sex cells (gametes) from your parents –
they come in pairs
Plant cloning
Cuttings
Tissue culture
•
•
•
•
•
•
•
Remove a small section of the plant
New roots and shoot will form to give
you a new plant
Rooting powders and moisture will
help the process
Quick and cheap
Genetically identical plants
Used commercially for orchids and
fruit trees
•
•
•
Expensive but allows thousands
of new pants from tiny piece of
plant
Use plant hormones to make a
small group of cells produce a
big mass of identical plant cells
Using hormones these can then
forma new plant
This guarantees all plants will
have the desired characteristics
Animal cloning
Embryo cloning
Adult cell cloning
Genetic engineering
Exam questions
[6 marks]
Theories of
Evolution
Classification and
evolution
B1.7 Evolution
Accepting Darwin’s
ideas
Natural Selection
Theories of Evolution
All species of living things alive today have evolved from the
first simple life forms
Jean-Baptiste Lamarck was a French biologist
His idea was that every animal evolved from primitive worms - The change was caused by
the inheritance of acquired characteristics
Problems: No evidence - People
didn’t like to think they
descended from worms People could see clearly that
changes were not passed onto
their children (e.g. Big muscles)
Darwin’s
Ideas
• Variation
• Mutation
• Adaptation
leads to survival
• Pass on genes
Darwin’s
Ideas
• Variation- In any
species there is
variation
• Mutation- Caused by
mutations in DNA
• Adaptation leads to
survival- Those with
better adaptations
will survive
• Pass on genespassing on their
genes to the next
generation
Accepting Darwin’s Ideas
Why did people object?
Religious – god made the world
Not enough evidence
No way to explain inheritance – genetics not
known about
Classification and Evolution
Species: A group of similar organisms that are capable of
interbreeding to produce fertile offspring
Evolutionary tree
DNA evidence used to
decide which species
an animal belongs to
and work out
evolutionary
relationships
Exam questions: