Biology Flashcards

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1
Q

What is a law? Provide 3 examples.

A
  • Predicts what WILL happen - the result
  • Resists change
  • Completes a task, though doesn’t explain why
  • Very rarely change
    E.g., Newtons 3 laws of motion. The Law of Conservation of Mass. The law of thermodynamics.
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2
Q

What is a theory? Provide 3 examples

A
  • Provides the most logical explanation to WHY something happens.
  • Multiple theories compete to explain something.
  • New theories come with new discoveries - more likely to change from new evidence. (replacable)
  • Can be used in conjunction with other theories.
    E.g., Theory of plate tectonics. Charles Darwin’s theory of evolution. Big Bang theory.
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3
Q

What is similar between Laws and Theories?

A

They both make predictions, support one another, are supported by evidence - validated, collect data and make conclusions.

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4
Q

Who came to the same conclusion about evolution and what does this prove?

A

Both Charles Darwin and Alfred Wallace came to the same conclusion about evolution - it further proves the reliability and validity of the theory.

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5
Q

Define species.

A

A group of individuals that can reproduce VIABLE offspring - e.g., a mule is not viable.

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6
Q

What does VASRP stand for?

A

Variation
Adaptation
Survival
Reproduction
Population changes over time

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7
Q

What is the mimicking adaptation?

A

Prey take on the same colouration/phenotypes as predators/venomous animals. This allows them to avoid predation as original predators avoid them because of their looks.

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8
Q

What law did Alfred Wallace propose?

A

In 1855, Wallace proposed: ‘Every species has come into existence coincident both in time and space with a pre-existing closely allied species.

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9
Q

What is evolution?

A

Any change in the heritable traits* within a population across generations. IT IS A NATURAL PROCESS.
* Can be inherited/passed to subsequent offspring/generations via genes in DNA.

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10
Q

What is reproduction?

A

The duplication of DNA and passing it on to future generations.

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11
Q

What is DNA?

A

A chain-like chemical stored inside each cell which tells them how to grow and function. It contains coded information on how to build an organism.

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12
Q

How does DNA mutation occur?

A

When being copied, errors can occur which modify the DNA code - causing a change to the DNA code sequence.

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13
Q

What is natural selection?

A

The process through which populations of living organisms adapt and change to produce order and complex functions.

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14
Q

What is genetic variation?

A

The difference in DNA sequences between individuals within a population.

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15
Q

What does DNA stand for?

A

Deoxyribonucleic Acid.

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16
Q

What is a phenotype?

A

The physical expression of genes for a trait. E.g., blonde hair.

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17
Q

What is a trait?

A

The features/characteristics of an organism.

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18
Q

What is the theory of evolution?

A

That all organisms descended from a common ancestor.

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19
Q

What are the 6 main pieces of evidence to explain the theory of evolution?

A

Fossil evidence.
Comparative anatomy.
Plate tectonics.
Galapagos Islands.
Embryology.
Gene and DNA comparison.

20
Q

How does fossil evidence explain the theory of evolution?

A
  • Fossils form if the dead organism is quickly covered in sediments.
  • The depth of the fossil indicate how recent the organism died.
  • The structural change and development is observed.
    Fossils show how life on earth was, and allows for comparison – between species then and now.
21
Q

How does comparative anatomy explain the theory of evolution?

A
  • A comparison of the bone structure of species.
  • The arrangement and order of bones are compared to one another.
  • Indicates that organisms share a common ancestor.
  • Body parts share similar qualities/looks, but not necessarily function.
22
Q

How do plate tectonics explain the theory of evolution?

A
  • Provides environmental pressure that stimulates populations to adapt/evolve.
  • Shows movement between areas to form landforms.
  • Explains how major landforms are created as a result of Earth’s movement.
23
Q

How do the Galapagos islands explain the theory of evolution?

A
  • Species have common features, but individual traits - forming distinctive groups.
  • Different environments lead to different characteristics.
  • As isolation increased, reproduction ceased.
  • Mutations add new DNA to the gene pool.
  • The animals that are not suited to the environment die due to natural selection.
24
Q

How does embryology explain the theory of evolution?

A
  • The initial stage of development in a multicellular organism.
  • Shows how present-day organisms have evolved/changed.
  • Some structures can only be seen in embryo development e.g., tails.
  • Studies development of the anatomy of an organism from child to adult.
25
Q

How do gene and DNA comparison explain the theory of evolution?

A
  • Genes/DNA are used to compare genetic information between organisms.
  • Mutation rates can infer the last common ancestor between organisms.
  • Shows how related organisms are.
26
Q

What is a population?

A

All individuals of the same species in a particular location.

27
Q

What is a community?

A

The living organisms of different species in the same area.

28
Q

What is an ecosystem

A

The interaction between abiotic and biotic factors of an environment.

29
Q

What is the archaeopteryx?

A

A transition fossil between bird (wings and feathers) and reptile (scales and tail)

30
Q

What are some ways in which the Galapagos Island finches evolved?

A

The isolation of the original population spread between different environmental conditions - causing different traits to become advantageous.
Beak shape varied e.g., short, sharp, stubby, etc.

31
Q

What is the process of natural selection?

A

Variation - Individuals experience differences in specific traits than others in the same population - same species, same location.
- Variation is the result of mutations in DNA - not acquired, only genetic.
Adaptation - Environmental conditions/changes to the environment may select for some variations of a specific trait to become advantageous to survival or reproduction.
- This occurs by CHANCE and is NOT A CHOICE. Individuals are already adapted because it is in their genes.
Survival - Individuals with the adaptation will survive better than individuals without that adaptation as they are more likely to survive.
Reproduction - Individuals that survive can therefore reach sexual maturity and are more likely to pass the advantageous genes (DNA) in their gametes* to offspring.
Population changes over time - Over MANY generations, more individuals in the population will likely posses the advantageous trait (adaptation) making it the most common genotype/phenotype for that trait.
(*Gametes –> sperm or ova)

32
Q

What are the main aspects about nature vs nurture?

A

Nature are the features/characteristics that the organism was born with - in their DNA.
Nurture is the development of those traits as a result of the environment/experiences e.g., loving mother, loving child, bad mother, bad child - same genetics, different exposure - different outcomes.

33
Q

Which bases join together to create DNA?

A

Adenine and Thymine (A and T)
Guanine and Cytosine (G and C)

34
Q

What is Mitosis?

A

The process where one parent cell divides to produce two identical daughter cells. It is the type of cell division responsible for growth and repair.

35
Q

Describe the process of Mitosis.

A

Prophase - Duplicated chromosomes condense.
- The nuclear membrane begins to break down.
Metaphase - Chromosomes line up at the equator of the cell.
- Fibres attach each chromosome to centrioles on opposite sides of the cell.
Anaphase - Duplicated chromosomes separate.
- Fibres pull sister chromatids apart.
Telophase - Nuclear membranes reform.
- Nuclei with identical sets of DNA are produced.
- Cell divides into daughter cells.

36
Q

What are x and y chromosomes?

A

Chromosomes which determine sex. Females have two x chromosomes (xx), while males have one x and one y chromosome (xy).

37
Q

What is meiosis?

A

A type of cell division that produces sex cells.

38
Q

What is a homologous pair?

A

Two chromosomes that contain versions of the SAME gene. One obtained from the mother, the other from the father.
*HOMO - means the SAME e.g., xx
* HETERO - means OPPOSITE e.g., xy

39
Q

Homo vs Hetero gene pair means…

A

Homozygous genes are when identical alleles of the gene are present on both homologous chromosomes. This can be represented by BB or bb.
Heterozygous genes is when one cell contains two different alleles of a gene. This can be represented as Bb or bB.

40
Q

What are dominant and recessive alleles?

A

Dominant allele are genes which are phenotypically/genetically displayed over recessive genes. E.g.,
Dominant allele –> Pp <– Recessive allele.
For a recessive gene to be represented, BOTH chromosomes must be the recessive gene - from both parents. E.g., pp.

41
Q

How is a gene different from an allele and a chromosome?

A

An allele is an alternate form of a gene which controls the expression of traits.
Chromosomes are coded with genes.

42
Q

Define genotype.

A

The genes and allele encoded in one’s DNA for specific traits.

43
Q

What is an acquired trait?

A

A feature that is gained during an individual’s lifetime e.g., an artificial change of hair colour, the loss of a limb, etc.

44
Q

What are the three types of adaptations?

A

Structural adaptation - organism’s body.
Behavioural adaptation - organism’s behaviour.
Physiological adaptation - organism’s internal processes.

45
Q

What is speciation?

A

The formation of a new species. It begins with an original species being separated and changing until the two new species can no longer breed fertile offspring.

46
Q

What is the structure and functions of the female reproductive system?

A

Uterus/womb - if an egg is fertilised, it will implant in the wall of the uterus and develop into a foetus.
Cervix - The opening/’neck’ of the uterus at the top of the vagina.
Vagina - Connects the cervix to the outside of the body - sperm is deposited there during sex.
Ova/ovum - The female sex cell.
Ovary - After puberty, an ovum is released from here every 28 days or so.
Oviduct/fallopian tubes - Carries the ovum from the ovary to the uterus where it can be fertilised.

47
Q

What is the structure and functions of the male reproductive system?

A

Sperm - The male sex cell - adapted to swim from the vagina to the egg.
Testes - After puberty, these make sperm continuously.
Scrotum - A sac of skin which holds the testes.