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general bio 2024 > Lecture 14 > Flashcards

Lecture 14 Flashcards

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Biology 101 flashcards
1
Q

Evolution

A
  • Accumulation of inherited change within a population over time
  • does not refer to changes that occur in an individual within its lifetime
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2
Q

What happens if a population accumulates enough change?

A

It constitutes a new species

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3
Q

What does natural selection leads to?

A

Adaptation

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4
Q

Evolutionary theory

A
  1. Cells make copies of themselves with genetic material, but sometimes the copy is not the same
  2. Cells with slight different traits
  3. Trait A may allow a cell to reproduce more than trait B
  4. More cells with trait A
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5
Q

Lamarck’s theory of evolution

A
  • One of inheritance of acquired characteristics
  • acquired traits were pass traits to offspring
  • a change in environment changes behavior
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6
Q

What are the two ideas developed by the origin of species?

A
  • Evolution explains life’s unity and diversity
  • natural selection is a cause of adaptive evolution
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7
Q

4 observations that the theory of evolution by natural selection is based on

A
  • Population size
  • availability of resources
  • variation in population (no 2 individuals are exactly alike)
  • individuals to survive and reproduce
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8
Q

Population size (theory of evolution by natural selection)

A
  • It would increase exponentially if all individuals that are born reproduced successfully
  • tend to be stable in size (except for seasonal fluctuations)
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9
Q

Carrying capacity (k)

A
  • Refers to the number of individuals who can be supported in a given area within natural resource limits
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10
Q

Availability of resources (theory of evolution by natural selection)

A
  • environmental resources are limited
  • organisms compete for limited resources
  • death: or by predators, disease, unfavorable environmental conditions
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11
Q

What can the production of more individuals lead to? (Availability of resources)

A

Struggle for existence among individuals of a population, with only a fraction of their offspring surviving

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12
Q

What kind of limited resources organisms compete for?

A
  • Food
  • water
  • light
    -Space
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13
Q

Variation in population (theory of evolution by natural selection)

A
  • Members of a population vary extensively in their characteristics
  • no two individuals are exactly alike
  • variations are inheritable
  • survival depends in part on inherited traits
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14
Q

What individuals are likely to leave more offspring than others? (Variation in population)

A

Individuals whose inherited traits give them:
- a high probability of surviving
- a high probability of reproducing

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15
Q

Individuals to survive and reproduce (theory of evolution by natural selection)

A
  • This unequal ability of individuals to survive and reproduce
  • will lead to a gradual change in a population, with favorable characteristics accumulating over generations
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16
Q

More supporting evidence for Darwin’s theory of evolution

A
  • Evolutionary homology
  • molecular homologies
  • biogeography
  • homoplasy
  • the fossil record
17
Q

3 important points about evolution through natural selection

A
  1. Natural selection:
    - occurs through interactions between individual organisms and their environments
    - individuals do not evolve
    - can only act on heritable traits
  2. Environmental factors vary from place to place and from time to time
18
Q

What is the smallest group that can evolve?

A

The population

19
Q

How is evolutionary change measured?

A

Changes in relative proportions of heritable traits in a population over successive generations

20
Q

homology

A

Similarity resulting from common ancestry

21
Q

Evolutionary homology

A
  • Pomology
  • homologous structures between organisms
  • anatomical resemblance that represent variations on a structural theme that was present in a common ancestor
22
Q

Example of Evolutionary homology

A

Human forearm, cat forelimb, whale front flipper, bat wing
- different in appearance
- strikingly similar arrangement of bones, muscles and nerves

23
Q

Homologies: embryonic development

A

Example:
- all vertebrate embryos have structures called
Pharyngeal pouches in their throat
- these embryonic structures develop into very different, but still homologous adult structures (like gills in a fish)

24
Q

Vestigial organs

A
  • Seemingly useless organs or structures
  • indicate that the organism evolved from ancestors in which the organ was functional
  • tend to persist as there is no selective pressure to eliminate them
25
Q

Molecular homologies

A
  • Molecular evidence for evolution includes the universal genetic code and conserved sequence of amino acids en proteins and of nucleotides in DNA
  • genetic code is virtually universal
26
Q

Evidence of a common ancestor (molecular homologies)

A
  • Universal code (nucleotides)
  • genes that are shared among organisms inherited from a common ancestor
27
Q

Biogeography

A
  • The geographic distribution of species
  • formed an important part of Darwin’s theory
  • species from the same area tend to be more closely related to each other, even from species in other areas with the same of clay
28
Q

Pangea

A
  • Continents once joined together
  • as time evolved, each continental plates moved (plate tectonics)
  • resulted in populations becoming isolate in different environments, evolved differently
29
Q

Homoplasy

A
  • Occurs when characters are similar, but are not derived from a common ancestor
30
Q

Homoplastic features

A

Demonstrate that organisms with separate ancestors may adapt in similar ways to similar environmental demands

31
Q

Convergent evolution

A
  • Some similar mammals that have adapted to similar environments
  • have evolved independently from different ancestors
  • does not provide information about ancestry
32
Q

The fossil record

A
  • Shows that evolutionary changes have occurred over time in various groups of organisms
  • over longer time scales, fossil document the origin of major groups of organisms
  • provides evidence about the pattern of evolution
33
Q

Succession of forms observed in the fossil record

A
  • Consistent with other inferences about the major branches of descent in the tree of life
34
Q

Prokaryote, eukaryotes and the fossil record

A
  • Considerable evidence suggests that prokaryotes are the ancestors of all life and should precede all eukaryotes in the fossil record
  • oldest known fossils are prokaryotes
35
Q

What is a theory, in science?

A
  • Accounts for many observations and data
  • attempts to explain and integrate a great variety of phenomena
36
Q

When does a unifying theory become widely accepted?

A
  • Its predictions stand up to thorough and continual testing by experiments and additional observation

general bio 2024 (22 decks)

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