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Ib biology > Topic 5 > Flashcards

Topic 5 Flashcards

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1
Q

What can occur if there is variation among the same species?

A

Natural selection

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2
Q

Variation

A
  • typical populations may vary in many aspects
  • variation in humans is obvious ie hair colour, height
  • with many species the variation may not be obvious
  • needed for natural selection
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3
Q

What causes variation?

A

-Meiosis, mutation and sexual reproduction

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4
Q

Why is mutation a source of variation?

A

New alleles are produced which increases the gene pool

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5
Q

Why is meiosis a source of variation?

A
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6
Q

Why is sexual reproduction a source of variation?

A
  • involves the fusion of male and female gametes.

- The gametes usually come from different parents, so the offspring has a combination from two individuals

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7
Q

What is the only source of variation for species that do not undergo sexual reproduction?

A

Mutation

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8
Q

Adaptation

A
  • characteristics that make an organism better suited to life
  • develop by natural selection
  • do not develop during the lifetime of one individual
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9
Q

Overproduction

A
  • when species produce more offspring than the environment can support
  • lead to struggle for resistance as there will be a competiton for resources
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10
Q

Differential survival and reproduction

A
  • Individuals that are better suited to survive produce more offspring while those who are less adapted die or produce less
  • natural selection
  • Giraffes with longer necks are better suited to survive
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11
Q

What is heritable?

A

When the variation can be passed on

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12
Q

When does evolution occur?

A

When the heritable characteristics of a species change

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13
Q

What is another definition for biological evolution?

A

A change in the allele frequency of a population’s gene pool over successive generations

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14
Q

What provides evidence for evolution?

A

-Selective bredding of animals by artifical selection and fossil records

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15
Q

Fossils

A

-preserved reamins of an organism
- revealing features of an ancestor to compare with living descendants
- can provide direct evidence of ancestoral forms
-

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16
Q

Describe the law of fossil succession

A
  • fossils are dated by determining the age of the layer they are found
  • lower layers are older and higher layers are above
  • can be used to indicate a sequence of movement as prokaryotes appear in the fossil record before eukaryotes
  • and ferns appear before flowering plants
17
Q

What do archaeopteryx link together?

A

An example of a transitional fossil is archaeopteryx, which links the evolution of dinosaurs (jaws, claws) to birds (feathers)

18
Q

What is selective breeding a form of?

A

Artifical selection

19
Q

Describe the process of selective breeding

A
  • breeding members of a species with a desired trait thus making the frequency more common
  • ## targeted breeds can show variation in a very small time
20
Q

What 3 animals are commonly domesticatdly bred?

A
  • Horse, cow , dog
21
Q

Give an example of selective breeding?

A

Greyhounds ( racing dogs) were breed to be sleak and fast to race

22
Q

What are homologus structures?

A

Anatomical features that are similar in basic structure despite being used in different ways

23
Q

Adaptive radiation

A
24
Q

Comparison of the pentadactyl limb of mammals, birds, amphibians & reptiles

A
  • Pentadactyl limb has 5 fingers
  • Human hands are adapted for tool manipulation (power vs precision grip)
  • Bird and bat wings are adapted for flying
  • Horse hooves are adapted for galloping
  • Whale and dolphin fins are adapted for swimming
25
Q

What does continuous variation match?

A

Gradual divergence

26
Q

Continuous variation

A
  • within a population there will be genetic variation
  • normally follows a normal distribution curve
  • if two populations are separated they may experience different conditions and will overtime adapt to those said conditions and gradually diverge from one another
  • the degree of the divergence will depend on the amount of time separated and the extent of the separation as populations in close proximity = less variation
27
Q

What is speciation?

A
  • the process by which two related populations can diverge into separate species by evolution
  • the populations may diverge to a point where they can no longer interbreed to produce fertile offspring
28
Q

What are the features of bryophyta?

A
  • reproduce by releasing spores
  • mosses, liverworts
  • no xylem or phloem
  • no true roots – rhizoids
29
Q

What are the features of filicinophyta?

A
  • have leaves, roots and stems
  • have xylem and phloem
  • ferns
  • reproduce by releasing spores from clusters
30
Q

What are the features of coniferophyta?

A
  • confiers
  • have leaves roots and stems
  • have xylem and phloem
  • reproduce by seeds
31
Q

What are the features of angiospermaphyta?

A
  • have roots, stems and leaves
  • have xylem and phloem
  • all floweing plants and grass
  • reproduce by seeds in fruits

Ib biology (11 decks)

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