Transcript Living Things

INTRODUCTION
Science 3001
Science II: Earth & Life Sciences I
Mr. Kishore Lal
Living Things
Lesson 1B
Living Things - Single Cells
Single Cell or Multicellular?
Imagine… You are a single living cell…Imagine the organism as
liquid in a balloon!
Survival… is the game…
What are your needs?
What are the challenges you face?
Discuss the dangers / challenges you face and adaptations
required for survival if you are in water (aquatic)…
Food? Make food or hunt for food?
Oxygen for Respiration? Simple diffusion or specialized
structures?
Waste products of metabolism? Simple diffusion or special
structures?
Living Things - Single Cells
Reproduction? Simple division or specialized structures?
Sensing the environment?
Growth? Comes back to food and energy and getting rid of waste!
Movement? Cilia and flagella
Physical characteristics? Like Size? Shape? Colour? Phase of
matter? Structure?
Would it be easier to live in water (aquatic) or land (terrestrial)?
Are these challenges better overcome by joining together with
other cells?
Cell specialization… instructions for simple cells to specialize?
Living Things - Multiple Cells
Imagine…
You are a several living cells working together…Imagine the
organism as several liquid filled balloons of different kinds!
Survival… is the game…
What are your needs?
What are the challenges you face?
Discuss the dangers / challenges you face and adaptations
required for survival if you are in water (aquatic)…
What is the ‘glue’ to hold the cells together?
How does ‘stuff ‘ get to all cells?
Food? Make food or hunt for food?
Oxygen for Respiration? Simple diffusion or specialized
structures?
Living Things - Multiple Cells
Waste products of metabolism? Simple diffusion or special
structures?
Reproduction? Simple division or specialized structures?
Sensing the environment?
Growth? Comes back to food and energy and getting rid of waste!
Movement? Cilia and flagella
Physical characteristics? Like Size? Shape? Colour? Phase of
matter? Structure?
Would it be easier to live in water (aquatic) or land (terrestrial)?
Are these challenges better overcome by joining together with
other cells?
Cell specialization… instructions for simple cells to specialize?
Living Things – Living in Water
What , if any challenges face an organism trying to adapt to living
in water (aquatic)?
Fresh water? Salt water? Makes a difference?
Salt and Water Problems…
Drying out? Or becoming waterlogged?
Not a problem you think! Think again…
Living Things – Living in Water
Excretion
Problem - Maintaining Salt balance in the body…Ingesting salt
with food or water… salt must be excreted to maintain salt
balance in the living organism…
Organisms in fresh water will ‘swell up’.
Organisms in salt water will ‘dehydrate’
Solution - Specialized Excretory Structures e.g. red mangroves
excrete salt in their leaves…discuss… some animal have
kidneys…
Specialized water proof outer layer skin or bark?
Science - Diffusion in general and Osmosis in living
organisms…
Active transport of the salt against osmosis and diffusion.
Living Things – Living in Water
Nutrition
Problem: Obtaining Food
Solution: Make food or hunt (or variations of hunting)
Science: [To be discussed later in detail. (TBDLID)]
Solution: Organisms which make food – have specialized
structure for making food – chloroplasts…
Science: Make sugar from the simple inorganic substances
(photosynthesis) and go on to use these to make the tissues of
their bodies.
Living Things – Living in Water
Nutrition
Problem: How do they get raw materials and light? Does
simple diffusion work or are specialized structures needed?
Solution: Physical shape - Why are seaweed (plants) made
up of long strands instead of ‘bulk’? and cyanobacteria are
very small! Why?
Science: Diffusion and osmosis require large surface area.
Having long flat strands increase surface area to volume
ration making obtaining sunlight, raw materials and getting
rid of water by simple diffusion workable. Remember the
salt excretory mechanisms?
Living Things – Living in Water
Nutrition
Problem: Light intensity as you go deeper or water gets
dirty.
Solution: Surface dwellers or close to surface?
Second Solution: In the deep dark ocean food is made by
chemosynthesis
Science: Chemo synthetic bacteria use the minerals in
underwater volcano vents for energy to make simple
inorganic materials into sugars and starches.
Living Things – Living in Water
Nutrition
Solution: Organisms which feed – Need some kind of digestive
system… TBDLID
Digestion may be internal or external.
What advantages do animals have with the ability to move
about? Mechanisms for moving about TBDLID.
Science: Digestive organs break down complex food into
simpler organic components to be used by the organism for
generating energy, repairing tissues, growth and reproduction.
Living Things – Living in Water
Respiration
Problem: Obtaining energy for living processes like growth,
tissue repair, reproduction, movement and biochemical
processes.
Solution: Use the energy from food carbohydrates
Science: Respiration (obtaining energy from food) is done in
living cells in the mitochondria. There are two types of
respiration:
Aerobic – oxygen is required and carbon dioxide and water
are waste products.
Anerobic – does not require oxygen and can produce toxic
products like alcohol, methane, hydrogen suphide.
Aerobic respiration produces more energy from the same
food and has less toxic waste.
Living Things – Living in Water
Aerobic respiration
Problem: Obtaining oxygen and excreting the carbon dioxide…
Solution: Oxygen is obtained from the water
Science: Water dissolves the gases in air. There is dissolved
oxygen in the water. Some organisms rely on simple diffusion
(recall the surface area to volume ratio discussed earlier) and
this is a limiting factor. Some organism have gills which may
actively pass water over them to exchange oxygen and carbon
dioxide. Note though the water molecule (H2O) has oxygen,
this is unavailable as it is bound to the hydrogen and cannot
be extracted by the living things discussed. Gaseous
exchange can be done by simple diffusion e.g. Amphibians
like frogs can use their skin for while fish use their gills.
Living Things – Living in Water
Growth
Problems: What are some issues with increased size?
1. Decreased surface to volume ratio leading to inefficiency in
diffusion and osmosis. (Dealt with earlier in Excretion and
Nutrition)
2. I support of the body a problem in water where the density
of the body is close to that of water?
Solution: Living things in water can grow much larger than on
land. e.g. kelp forests (seaweed) off the California coast or the
Giant Octopus.
Science: water supports the organism on all sides pushing up
against gravity so it ’floats’ thus there are no large forces to
cause it to collapse into a heap.
Living Things – Living in Water
Sensitivity
Problems: What are some issues with sense organs in water
Solution: Living things can detect energy exchanges in their
environment to ‘sense their surroundings’
Science: Sound travels faster and more efficiently in water so
some organisms may exploit this. e.g. Dolphins use echo
location to find food, whales use whale songs to communicate
at low frequencies. Some fish have a sound sensitive line on
their side called the lateral line.
Light can only penetrate to a certain depth and the blue end of
the spectrum is more penetrating. Eyes are only useful near
the surface and many deep sea creatures are blind.
Electricity: Some fish can sense electrical impulses from the
nerves of other living creatures
Living Things – Living in Water
Sensitivity
Electricity or electromagnetic waves: Some fish can sense
electrical impulses from the nerves of other living creatures
and thus be aware of them.
Some animals have sensors in the skin that are sensitive to
light and deep pressure, pain, heat, and cold. These are not
present in creatures with exoskeletons. Some fish e.g. catfish
have whiskers which are sensitive to touch and allow them to
hunt in murky waters.
Taste and Smell: These are generally well developed in
aquatic animals. Chemicals in the water are sampled for taste
and smell.
Living Things – Living in Water
Movement
Problems: What are some issues with movement in water
Shape for water resistance?
Appendages for producing force
Appendages for ‘steering’
Solution: Aquatic animals have develop streamlined shapes for
more efficient locomotion.
Fins help steer aquatic animals and tail fins usually produce
thrust. Modified legs in turtles for e.g. also produce trust.
Science: Streamlined shape means less energy needed for
movement. Fins act as hydroplanes to move the fish up and
down in the water and from side to side. Tails push against the
water and thus the water pushes against the fish to move it.
Living Things – Living in Water
Reproduction
Problems: Are there advantages to asexual reproduction?
What problems face aquatic animals trying to reproduce
sexually?
1. Reproduction outside the body
2. Drying out of the eggs
3. Meeting of sperm and ovum in the water
4. Safety of the offspring
Living Things – Living in Water
Solution: Many aquatic female fish release eggs which are
fertilized by the male outside the body. Aquatic mammals may
have internal fertilization. Since the eggs remain in water they
will not dry out. Sperm have the water to swim to the eggs.
Fish usually produce many offspring (safety in numbers).
Is there any kind of parenting?
Science: How efficient is fertilization outside the body?
Does it result in a waste of resources
Do many aquatic organisms simply live to reproduce?
Living Things – Living in Water
Physical Limitations:
Problems: Safety?
Solution: Body Armor? Camouflage?
Science: Function of Scales? Sharp teeth? How does
camouflage work?
Living Things – Vertebrates living in Water
Characteristics of Fish: Most fish
• Are cold-blooded – Advantage or disadvantage?
• Are streamlined in shape – to reduce water resistance for
easier movement.
• Have internal bones including backbone (Vertebrate) – for
support and movement.
• Have fins – movement balance, steering and propulsion
Living Things – Vertebrates living in Water
• Have scales – protection from harm and infection, as well as
reduce water resistance for easier movement.
• Have gills – extract dissolved oxygen in the water
(breathing) and excrete waste like ammonia and salts
• Have kidneys for excreting salts and water
• Have a swim bladder or air bladder - by regulating the
amount of air in the bladder, fish can adjust the depth at
which they float without continuously having to swim. Also
used when oxygen content of the water is low.
Living Things – Vertebrates living in Water
• Have nostrils and are able to detect scents in water
• Have a lateral line on their side with small sensory hairs to
detect underwater vibrations in low light or murky water.
• Reproduce by laying eggs
• Eggs are fertilized outside the body.
• Have circulatory systems
• Have digestive systems – some are herbivores and others
omnivores or carnivores
Living Things – Vertebrates living on Land
• Are fish the only vertebrates living in water?
• Name some animals (except fish) which live in water
• What characteristics (physical, physiological and behavioral)
do other vertebrates which live in water share with fish?
Living Things – Living on Land
Adapting to living on Land
What , if any challenges face an aquatic organism trying to adapt
to living on land (terrestrial)?
How would fish have to adapt to living on land?
Problem: Loss of watery environment to a dryer air environment…
Living Things – Living on Land
Adapting to living on Land
Growth and Movement: Needs some kind of skeleton to support
the body and facilitate movement
Solution:
• Internal bones form a skeleton with joints and attached to
muscles, Legs
• Plants – develop roots and use cellulose cell walls for
support
Science: Skeletal System, Plant structures.
Respiration Problem: Obtaining oxygen from the air instead of the
water…
Solution:
• Development of lungs
• Using the skin to exchange gases (breathe)
Science: Mechanics of breathing
Living Things – Living on Land
Adapting to living on Land
Excretion: Preventing water and excess salt loss.
Solutions:
• Skin to prevent water loss
• Kidneys to excrete excess salts and water
• Membranes to prevent eyes from drying out
Sensitivity: Perception of the surroundings
Solution: Sense organs
Science: How the sense organs work.
Living Things – Living on Land
Adapting to living on Land
Nutrition: Making food or obtaining food.
Solution:
• Plants – develop roots for obtaining water and minerals and
use cellulose cell to support branches and leave to catch
sunlight
• Animals eat plants or other animals or both.
Science:
• Photosynthesis
• Food chains and Webs
• Ecosystems
Living Things – Living on Land
Adapting to living on Land
Reproduction: Drying out of gametes (eggs and sperm).
Solution:
• Plants – develop structures for reproduction
• Animals eat plants or other animals or both.
Science:
• Photosynthesis
• Structures for reproduction in plants e.g. spores and flowers,
fruits and seeds in flowering plants
• Animal reproductive structures
• Food chains and Webs
• Ecosystems
• Protection of eggs:
• Unshelled
• Leathery skin
• Calcified shells
• Kept inside the female body
Living Things – Living on Land
Adaptation to living on Land
Growth:
• Exo-skeletons require moulting
• Internal skeletons require less rigorous moulting and avoind
the hazards of exo-skeleton moults.
Respiration:
• Use of the skin for breathing (simple diffusion)
• Development of lungs (large surface for diffusion)
• Metamorphosis - Juvenile stage may have gills and adult
lungs
Science of Respiratory Surface
• small diffusion barrier
• large surface area
• blood supply
• ventilation
Living Things – Living on Land
Adaptation to living on Land
Sensitivity:
• Complex nervous system to receive stimuli from the
environment
• Sense organs
Living Things – Vertebrates living 0n Land
Summary of Characteristics of Amphibians
Amphibians usually:
• Are cold-blooded – Advantage or disadvantage?
• Many use the skeleton and limbs for movement as adults
but have fins as juveniles
• Lay eggs in water with external fertilization
• Undergo metamorphosis
• Juveniles have gills and obtain oxygen from water
(breathe)
Living Things – Vertebrates living 0n Land
Summary of Characteristics of Amphibians
Amphibians usually:
• Adults develop lungs and obtain oxygen from the air
• Adults also use moist skin to obtain oxygen from the air.
Skin has many capillaries.
• Have kidneys for excreting salts and water
• Have nostrils and are able to detect scents in air
• Juveniles may have the lateral line like fish.
• Have circulatory systems
Living Things – Vertebrates Living on Land
Summary of Characteristics of Amphibians
Amphibians usually:
• Have circulatory systems
• Have digestive systems – some are herbivores and others
omnivores or carnivores
Questions:
1. How successful are amphibians in adapting to and hence
colonizing terrestrial environments?
2. What are the similarities and differences from fish?
3. Are amphibians the only vertebrates on land?
4. What characteristics (physical, physiological and behavioral)
do other vertebrates which live on land share with
amphibians?
Living Things – Vertebrates Living on Land
Amphibian Challenges
Problem: Eggs consists mostly of jelly – very susceptible to rapid
dehydration if exposed to the air
Solution: deposit their eggs directly into the water or damp
locations under rocks and logs
Science: Amphibians usually
• Lay eggs in water
• Undergo metamorphosis
• Juveniles have gills and obtain oxygen from water (breathe)
• Adults develop lungs and obtain oxygen from the air
• Adults also use skin to obtain oxygen from the air
Living Things – Vertebrates Living on Land
Amphibian Challenges
Problem: Skin is used for breathing (obtaining oxygen from the
air)
Solution:
• Range limited to wet conditions
• Tend to nocturnal or only active in rainy weather
• Hibernate under mud when conditions get dry.
Problem: Cold-blooded so only active in warm weather.
Solution: may have poison glands to deter predators
Living Things – Vertebrates Living on Land
Summary of Characteristics of Reptiles
Reptiles usually:
• Are vertebrates. Many use the skeleton and limbs for
movement
• Are cold-blooded
• Lay eggs on land (do not need water) with leathery shell
• Internal fertilization
• Tough and scaly skin. Why?
• Have lungs for obtaining oxygen from air
Living Things – Vertebrates Living on Land
Summary of Characteristics of Reptiles
Reptiles usually:
• Have kidneys for excreting waste
• Have digestive systems
Questions:
1. How successful are reptiles in adapting to and hence
colonizing terrestrial environments?
2. What are the similarities and differences from fish and
amphibians?
3. Are reptiles the only vertebrates on land?
4. What characteristics (physical, physiological and behavioral)
do other vertebrates which live on land share with reptiles?
Living Things – Vertebrates Living on Land
Summary of Characteristics of Birds
Birds usually:
• Are vertebrates. Use the skeleton and limbs for movement
• Are warm-blooded. Advantage or disadvantage?
• Have feathers for flight and to keep warm
• Lay eggs on land (do not need water) with calcified shell
• Internal fertilization
• Have very efficient lungs for obtaining oxygen from air
• Have kidneys for excreting waste.
Living Things – Vertebrates Living on Land
Summary of Characteristics of Birds
Birds usually:
• Have digestive systems
• facilitate flight with
• hollow bones for light weight, beaks but no teeth
• do not store urine or feces
• feathers
• Huge chest muscle with efficient heart and circulatory
system.
Living Things – Vertebrates Living on Land
Summary of Characteristics of Birds
Questions:
1. How successful are birds in adapting to and hence
colonizing terrestrial environments?
2. What are the similarities and differences from fish,
amphibians and reptiles?
3. Are birds the only vertebrates on land?
4. What characteristics (physical, physiological and behavioral)
do other vertebrates which live on land share with birds ?
Living Things – Vertebrates Living on Land
Summary of Characteristics of Mammals
Mammals usually:
• Are vertebrates. Use the skeleton and limbs for movement
• Are warm-blooded
• Have hair or fur to keep warm
• Internal fertilization with special reproductive organs for
fetal development
• Have very lungs for obtaining oxygen from air
• Have specialized structure (diaphragm) as well as rib muscles
for breathing
• Have kidneys for excreting waste
Living Things – Vertebrates Living on Land
Summary of Characteristics of Mammals
Mammals usually:
• Have organs (mammary glands) for producing milk for their
young
• Have digestive organs includingspecialized teeth and
• Efficient hearts and circulatory system
Questions:
1. How successful are mammals in adapting to and hence
colonizing terrestrial environments?
2. What are the similarities and differences from fish,
amphibians, reptiles and mammals?
3. Are mammals the only vertebrates on land?
4. What characteristics (physical, physiological and behavioral)
do other vertebrates which live on land share with mammals?
END