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SB4 Flashcards

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Biology 101 flashcards
1
Q

Which characteristics have changed during the evolution of humans and how have they changed?

A
  1. Skull volume - increased
  2. Length of bones
    * Length of arms - decreased
    * Height - increased
  3. Toes - shorter and no longer curved
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2
Q

What are all the names of the human-like species?

A
  1. Ardipithecus ramidus (Ardi)
  2. Australopithecus afarensis (Lucy)
  3. Homo habilis
  4. Homo erectus
  5. Homo sapiens
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3
Q

Why is the fossil record incomplete?

A
  1. Some of the fossils are being destroyed
  2. Some are not discovered yet
  3. Some are fully decomposed not leaving behind anything
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4
Q

Why did humans think to create stone tools? (5 reasons)

A
  1. Hunt animals
  2. Kill
  3. Build shelter
  4. Skinning animals
  5. Cutting meat
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5
Q

What are two ways of identifying the age of stone tools?

A
  1. Determine the age of the rock layer
  2. Carbon dating
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6
Q

What is evolution?

A

The gradual change in the characteristics of a species over many generations.

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7
Q

What is natural selection?

A

The environmental factors such as disease, predation, climate, change the characteristics of the species in order to be able to survive (survival of the fittest).

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8
Q

How does evolution occur through natural selection?

A

Individuals within a species may show variation because of differences in their genes.

The individuals with characteristics most suited to the environment are more likely to survive and breed successfully.

The alleles which have enabled these individuals to survive are then passed on to their offspring.

New alleles result due to mutation causing a more rapid change in species.

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9
Q

Explain the evolution of leopards and panthers.

A

[Check ‘Darwin’s Theory’ bottom of page 1]

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10
Q

Explain the evolution of bacteria resistant to antibiotics.

A

[Check ‘Darwin’s Theory’ top of page 2]

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11
Q

What is the pentadactyl limb?

A

A five-fingered limb structure that many vertebrates have including humans.

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12
Q

What does the pentadactyl limb suggest? Why?

A

It suggests that all the vertebrates that have the pentadactyl limb have evolved from a common ancestor.

This is because if the vertebrates had come to life independently you would expect them to each have differently designed limbs - but instead the parts of the limbs that they have are identical.

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13
Q

What is the pentadactyl limb composed of?

A
  1. Five phalanges
  2. Carpal
  3. Humerus
  4. Ulna
  5. Radius
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14
Q

How did different animals’ limbs adapt to their functions?

A

[Check ‘Development of Darwin’s Theory’ page 2]

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15
Q

What is speciation?

A

The formation of a new species, usually by geographical isolation.

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16
Q

What are the 7 classes in order?

A

Kingdom, Phylum, Class, Order, Family, Genus, Species.

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17
Q

How to recognise the genus and species of an organism?

A

Genus - first letter is capital, word is written in Italics
Species - first letter is small, word is written in Italics

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18
Q

What are the 3 domains of classification and what are their characteristics?

A
  1. Bacteria (cells with no nucleus and genes contain no unused sections of DNA)
  2. Archaea (cells with no nucleus but unused sections of DNA in genes)
  3. Eukarya (cells WITH nucleus and genes have unused sections of DNA)
    a. Animals
    b. Plants
    c. Fungi
    d. Some protoctists

SOS: Check ‘Classification’ for 3-domain system drawing

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19
Q

What are the 5 kingdoms?

A

Animals, Plants, Fungi, Protists, Prokaryotes.

SOS: Check ‘Classification’ for kingdom table

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20
Q

How can we tell two organisms are closely related?

A
  1. Common DNA - the more common DNA they have the more closely related they are
  2. They belong in the same genus
  3. Genetic analysis - analysis of DNA of organisms in order to determine which classification group they belong in
21
Q

How are vertebrates classified in the Linnaean system of classification?

A

They are classified into 5 groups.

  1. Mammals - warm-blooded, have hair/fur, breathe with lungs and give birth to live young
  2. Reptiles - cold-blooded, have dry scales and lay leathery eggs
  3. Amphibians - cold-blooded, have soft permeable skin and lay eggs
  4. Birds - warm-blooded, have feathers and a beak and many can fly
  5. Fish - cold-blooded, breathe through gills and lay many eggs
22
Q

How are new breeds and varieties of organisms created?

A
  1. Natural selection - nature chooses who is going to survive and pass on the favourable allele
  2. Artificial selection - humans choose the animals with the favourable characteristics and breed them together
  3. Genetic engineering
23
Q

What is selective breeding?

A
  1. Humans choose the organisms with the favourable characteristic and put them together to breed.
  2. Then, choose the offspring with that particular characteristic and put them together to breed.
  3. This process is repeated until they have organisms with that specific characteristic.
24
Q

What is genetic engineering?

A

A process that changes the DNA of an organism by adding extra genes for a favourable characteristic.

25
Q

What are organisms that contain DNA from another organism called?

A

Transgenic.

26
Q

What are GMO’s and why are they created?

A

GMO’s (genetically modified organism) are organisms that had their DNA changed.

This is done in order for the organisms to:
1. Produce certain substances (e.g. beta-carotene)
2. Have characteristics to allow to survive in different conditions (e.g. tomatoes not to freeze at extremely low temperatures)

27
Q

What are three uses of GMO’s?

A
  1. Create golden rice to produce beta-carotene to be taken by humans (humans that lack beta-carotene cannot make Vit A which can cause blindness)
  2. Create organisms that are resistant to disease-causing organisms
  3. Create organisms faster and to be larger than normal so that they provide more yield to feed the growing population
28
Q

What is tissue culture?

A

The growing of cells or tissues in either a liquid with nutrients or in a special gel called agar with nutrients.

29
Q

Where are stem cells found, what are they and what can they do?

A

Plants and animals have stem cells that are unspecialised cells that can differentiate into other cells and form tissues.

30
Q

What are the two ways of performing tissue culture with plants?

A

First way is by using a piece of the plant:
1. Put the plant in bleach solution to sterilise it so that all the microorganisms such as bacteria die and won’t compete with the plant for nutrients.
2. Place the piece of plant into a sterile agar (medium) that contains all nutrients needed for growth.
3. Add special hormones to the agar so that the plant develops shoots and roots.
4. Once the plant has grown enough then they plant them into soil or compost.

Second way is by using plant cells:
1. Put the plant in bleach solution to sterilise it so that all the microorganisms such as bacteria die and won’t compete with the plant for nutrients.
2. Take some cells and put them into a sterile medium so that they grow into a callus (a ball of unspecialised cells).
3. The callus will then develop plantlets.
4. Treat the plantlets with hormones so that it develops roots and shoots.
5. Take the plantlets and separate them and put them into a sterile medium so that they can grow.
6. Once the plants have grown enough, then they plant them into soil or compost.

31
Q

How is genetic engineering done with the use of bacteria? (8 steps)

A
  1. Locate the gene that you want
  2. Using restriction enzymes, cut the gene from the DNA
  3. Remove a plasmid from a bacterium
  4. Using the same restriction enzymes cut the plasmid open creating the sticky ends
  5. Add the gene for that particular characteristic
  6. Stick the gene on the plasmid using the enzyme DNA ligase
  7. Put the plasmid back in the bacterium
  8. Bacterium multiplies and also produces the protein of that gene
32
Q

What are the risks of selective breeding?

A
  1. Only a few alleles are selected to be passed on to the next generation, so other alleles disappear and that leads to less variation.
  2. If the organisms have very similar DNA and a condition changes (e.g. a disease strikes) they will all be susceptible to that disease and will all die.
  3. Animal welfare: when animals suffer (e.g. if they are made to produce meat, they are too heavy to move)
33
Q

What are the risks of genetic engineering?

A
  1. Crop seeds are more expensive so poor farmers cannot afford to buy them.
  2. Herbicide resistant crops can breed with weeds creating herbicide resistant weeds. This means when you spray the crops with herbicide, the weed will not die and will continue to compete with the crops for resources, causing the crop not to grow very much.
  3. Some people believe that eating GM food is very unhealthy and will create problems.
34
Q

What are the advantages and disadvantages of GM crops?

A

Advantages:
1. Herbicide resistant/faster growth
2. Increased yield
3. Less use of chemical pesticides
4. Less harm to living organisms
5. Fix health problems (such as Vit A deficiency - by creating beta-carotene rice)

Disadvantages:
1. Gene transfer due to cross pollination leading to superweeds
2. Greater competition between plant species
3. Reduction in biodiversity/non-target organisms are harmed
4. Long-term effects on human health/unknown side effects
5. Expensive to produce and buy
6. Have to rely on GM companies to buy (e.g. seeds)

35
Q

What are the advantages and disadvantages of GM bacteria?

A

Advantages:
1. Rapid population growth
2. Increased yield of product
3. Making insulin
4. No animals are harmed/used in production
5. Less side-effects
6. Suitable to be used by vegans

Disadvantages:
1. Long-term effects on human health/unknown side effects
2. Expensive to produce and buy
3. Risks in culturing microorganisms

36
Q

What are the advantages and disadvantages of GM animals?

A

Advantages:
1. Production of hormones

Disadvantages:
1. Long-term effects on human health/unknown side effects
2. Expensive to produce and buy

37
Q

What is a pest?

A

Any microorganism that damages or destroys crops/vegetables, leading to a decrease in the yield of crops.

38
Q

What can be used to prevent pests?

A

Pesticides such as insecticides are used to kill insects that damage crops.

39
Q

What are the disadvantages of using pesticides?

A
  1. Pests/insects might develop resistance to the pesticide
  2. Excess pesticides in soil would cause pollution in the environment
  3. Effects on food chains - if pests are killed, then their predators will not have food so they will also die
  4. Other insects could die just by sitting on the crops, killing useful insects such as butterflies and bees
40
Q

What are GM crops and what is their use?

A

Crops that release a toxin in their cells called B.t. toxin, which is lethal when the insect eats the crop. This means only pests will be killed, instead of all insects. However, not all pests can die from this toxin, so many farmers may need to spray with insecticides to kill other pests.

41
Q

What is the origin of Bt toxin?

A

Comes from the bacterium Bacillus thuringiensis, where the gene that produces the particular toxin is taken and inserted into the DNA of GM crops. This allows crops to produce the toxin.

42
Q

What is biological control?

A

Using organisms to control pests or weeds by killing them.

43
Q

What do fertilisers contain?

A

Mineral ions such as nitrates, potassium and phosphates.

44
Q

Why are nitrates important?

A

Nitrates are needed for making DNA, protein synthesis hence needed for plant growth.

45
Q

What are the advantages and disadvantages of fertilisers?

A

Advantages:
1. Increases crop yield

Disadvantages:
1. May cause pollution of surrounding water if too much is added, then leaking into lakes and rives when it rains
2. Harming other organisms and potentially killing them
3. Health problems for humans and animals drinking the polluted water

46
Q

What are the advantages and disadvantages of biological control?

A

Advantages:
1. No use of chemicals
2. Increase crop yield
3. No pollution

Disadvantages:
1. The predators may cause other damage, such as eating helpful insects that eat other pests
2. Eating the crop

47
Q

What criteria do farmers have to follow to get approval of implementing biological control?

A
  1. Control organism stays mainly within the crop
  2. Control organism selectively chooses to eat pests of the crop
  3. Control organism does not eat beneficial organisms or crop plants
48
Q
A

Science 4M1 (7 decks)

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