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Comparative anatomy > Chapter 1 exam 1 (lecture) > Flashcards

Chapter 1 exam 1 (lecture) Flashcards

1
Q

Primitive structure definition

A

original condition of a trait in the common ancestor

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2
Q

Example of a primitive structure

A

All vertebrates, share the primitive trait of a backbone which was first seen in their common ancestor, the jawless fish.

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3
Q

Derived structure definition

A

modification of a primitive trait

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4
Q

example of a derived structure

A

feather and hair both epidermally derived but have modifications that are significantly different visually.

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5
Q

Homologous structure definition

A

structure found in two or more descendants of a common ancestor
-similar anatomical position but may not have same function or appearance

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6
Q

example of a homologous structure

A

the bones that make up the wings in pterodactyls, bats and birds (ulna, radius etc) are homologous

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7
Q

Analogous structure definition

A

structure in 2+ organisms that looks similar and is used for the same function but has evolved independently

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8
Q

analogous structures are produced via what kind of evolution?

A

convergent evolution

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9
Q

what is convergent evolution

A

independent species evolve similar traits via adaptation to similar environments with similar selective pressures

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10
Q

example of analogous structures

A

wings in pterodactyl, bat and bird evolved independently 3 times with analogous wing shape.

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11
Q

Exaptation

A

pre-existing structure that is inherited from an ancestor but is used for an unrelated function

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12
Q

example of exaptation

A

Dinosaurs and birds both have feathers
- pre adaptive structure (original feathers) were used from thermoregulation
-via descent with modification, feathers were used for flight

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13
Q

Phylogenetic tree

A

hypothesis of evolutionary progression/ relationships

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14
Q

Phylogeny is often visualized with

A

evolutionary trees

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15
Q

Phylogeny definition

A

study of evolutionary relatedness among past and present taxonomic groups (relationships among living things through time)

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16
Q

Systematics includes both:

A
  1. taxonomy
  2. phylogenetics
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17
Q

phylogenetics definition

A

determining the evolutionary relationships among organisms

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18
Q

What is binomial nomenclature

A

2 terms to denote extant or extinct species. Both latin or Greek and italicized

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19
Q

what does the first term indicate in binomial nomenclature? is it capitalized?

A

genus, capitalized

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20
Q

what does the second term indicate in binomial nomenclature? is it capitalized

A

specific epithet, not capitalized.

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21
Q

Who came up with using binomial nomenclature to describe taxonomy

A

Caroli Linnaei

22
Q

In hierarchal classification, a named unit at any level of the hierarchy is considered a __________

A

taxon

23
Q

Who introduced a more modern approach of phylogenetic tree construction, aka Cladistics?

A

entomologist Willi Henning in phylogenetic systematics

24
Q

Cladistics is the classification of organisms based on _________ _________ characteristics that can be traced back to a groups most recent ancestor

A

Shared derived characteristics

25
Q

what types of heritable attributes/ characteristics are used for recognizing, differentiating or classifying a taxon?

A

morphological, embryological, physiological, behavioral, genetic

26
Q

What is a synapomorphy? Is it informative? provide an example.

A

-shared derived trait found in 2 or more taxa that are used to infer a phylogenetic relationship.
-informative
-ex: type of feather

27
Q

What is a symplesiomorphy? Is it informative? provide an example.

A

-shared primitive trait that is relatively unchanged from the ancestral form
-not informative, tells us nothing about relatedness
-bird symplesiomorphies: feathers and beaks

28
Q

What is an Autapomorphy? Is it informative? provide an example.

A

-a derived trait that is unique to only one group
-not informative, no shared trait therefore no relationship established
-ex: brain size in modern humans. not a trait shared by our closest relatives (chimpanzees or other hominins). distinguishes humans from other species but doesn’t help us determine the evolutionary relationships between humans, chimpanzees, and gorillas.

29
Q

What is an Homoplasy? Is it informative? provide an example.

A

-derived trait found in 2 or more taxa that did not arise from a common ancestor (basically analogous structure)
-not informative. similar traits evolved independently therefore do not reflect shared ancestry
-ex:wings of bats and birds . bat wings evolved from mammalian forelimbs, while bird wings evolved from reptilian forelimbs. similarity in wing function and structure is due to response to similar environmental demands (flight), not because bats and birds share a recent common ancestor with wings.

30
Q

Cladogram definition

A

branching diagram showing evolutionary relationships between taxa

31
Q

T/F? evolutionary trees are an example of a cladogram

A

True

32
Q

What is included in a Clade? what does it form?

A

-natural evolutionary lineage including the most recent ancestor and all of only that ancestors descendants
-forms a monophyly

33
Q

Monophyly definition

A

-a complete clade
- consists of the most recent common ancestor and all of its descendants

34
Q

Paraphyly definition

A

-an incomplete clade
-includes the most recent common ancestor but not all of its descendants
-aka homoplasy

35
Q

example of a paraphyly

A

fish
-sarcopterygian fish gave rise to tetrapods therefore “fish” is a paraphyletic group unless tetrapods are included (would then be monophylitic)

36
Q

polyphyly definition

A

an aritifical clade composed of unrelated organisms descended from more than one ancestor

37
Q

polyphyly example

A

ex: mammals and birds are both warm blooded but evolved independently

38
Q

sister taxa

A

groups of organisms that share immediate common ancestor and hence are each others closest relatives

39
Q

Crown group definition

A

-includes the most recent common ancestor of all living taxa of a particular group (plus any extinct descendants
-as long as there is 1 living organism, it is a crown group

40
Q

Stem group definition

A

-includes the extinct taxa related to but not part of the crown group
-extinct lineages that diverged below the most recent common ancestor of the group
-no living members

41
Q

the total group is the sum of:

A

Crown group + stem group

42
Q

isometric growth definition and example

A

-all structures of an organisms have the same rate of growth so that its shape is consistent throughout development
ex: salamander growth

43
Q

allometric growth definition and example

A

-certain structures of an organisms have a differential rate of growth in an individual throughout development
ex: humans -babies grow into their bobble heads

44
Q

The size of a species comes with what constraints? What do larger organisms need to get around these constraints? provide an example

A
  • as a species increases in size, its volume and mass (proportional to volume) increases faster than surface area
    -larger organisms need morphological specializations to allow for enough physiological exchange (gas and heat exchange, nutrient absorption)
    -ex: cilli and micovilli increase the surface area in gut to absorb nutrients, elephants have large ears to dissipate heat
45
Q

Heterochrony definition

A

-evolutionary changes in the timing or rate of developmental processes
-can lead to alterations in size, shape, and morphology between ancestors and their descendants.
-these changes can affect when certain traits/ structures appear or how long certain structures continue to develop

46
Q

Paedomorphosis definition

A

-“child form”
-juvenile traits of ancestors appear in the adults of descendants
- includes progenesis and neoteny

47
Q

neoteny definiton. provide an example

A

-Definition: Somatic (body) development slows down or is delayed, resulting in the retention of juvenile physical traits, but the organism eventually reaches sexual maturity.
-Key Mechanism: The overall development of the body is slowed, but reproduction happens at the usual time.
-chimp reproductive age is about the same as humans therefore humans likely developed in neotonic way

48
Q

Progenesis

A

-Definition: Reproductive development is accelerated, meaning the organism reaches sexual maturity earlier while its somatic (body) development remains in a juvenile form.
-Key Mechanism: Early reproductive maturity, but overall body development is not delayed; it just stops early.

49
Q

Peramorphosis definition

A

-“beyond form”
-organism’s development is extended beyond the typical endpoint seen in its ancestors. results in exaggerated/advanced traits compared to ancestral form.
-involves the prolongation or acceleration of developmental processes, leading to traits that are “beyond” what would normally appear in the ancestral species.

50
Q

hypermorphosis definition

A

-organism’s traits continue to develop for a longer time than usual, creating features that are larger or more complex than those of its ancestors.
-ex: irish elk
unusually large antlers grew for an extended period compared to its ancestors, leading to an exaggerated size as a result of prolonged development.

51
Q

acceleration definition (in terms of peramorphosis)

A

-growth rate of certain traits is faster than in the ancestral form.
-leads to the exaggerated or advanced appearance of those traits in the adult organism.
-involves reaching the final adult form more quickly, but with more pronounced traits.

Comparative anatomy (2 decks)

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