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BIO 100 General Biology > Unit 4: Evolution & Classification > Flashcards

Unit 4: Evolution & Classification Flashcards

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1
Q

Adaptation

A
  • Any evolved trait that helps an organism be more suited to its environment
  • A result of natural selection
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2
Q

Adaptive radiation

A
  • Proliferation of a species by adaption
  • Example: Darwin’s finches (beak shape & feeding in ecologically different islands)
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3
Q

Allele

A
  • Alternative versions of a gene
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4
Q

Analogous structures

A
  • Similar due to a common environment, not common ancestry
  • Examples
    • Wings of birds and insects
    • Eyes of octopi
    • Humans
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5
Q

Anatomic evidence that supports the theory of evolution

A
  • Homologous structures
    • Structures that are anatomically similar but have different functions
    • Example: The forelimbs of vertebrates. Forelimbs are composed of the same 5 bones, but serve different functions (ie wing, arm, etc.)
  • Embryonic similarities
    • Early embryos of all vertebrates are essentially identical
    • As development continues, these structures become modified for the specific adaptations of the organism
    • Example: Humans don’t have gills so the pharyngeal pouches develop into other structure
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6
Q

Anthropoid families

A
  • Monkeys
    • ie old & new world monkeys
  • Pongidae (“knuckle walker”/cannot walk upright)
    • ie great apes, orangutans, gorillas and chimpanzees
  • Hominid
    • ie humans
  • Primate tree:
    • Primates
      • Prosimian
      • Anthropoid
        • Monkeys
        • Pongidae
        • Hominid
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7
Q

Balanced polymorphism

A
  • When natural selection favors the ratio of 2+ phenotypes generation after generation
  • Example: sickle-cell diseases (Africa & malaria)
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8
Q

Biogeographical Study

A
  • Study of where organisms live on Earth, why they live there, and why they are not located in other places
  • 6 regions
    1. Australian: Australia
    2. Ethiopean: Africa
    3. Neartic: US & Canada
    4. Neotropical: S. America
    5. Orient: Indonesia
    6. Palaeartic: Europe/Asia
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9
Q

Biological evidence

A
  • Changes due to differential reproductive success in living organisms over geological time
  • Individuals that are better adapted to their environment produce more offspring than those that are not as well adapted
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10
Q

Bottleneck effect

A
  • When a population is reduced to near extinction and allele frequencies change
  • Surviving members rebuild the population but these members do not contain all the variation (alleles) possible
  • Examples
    • Cheetahs in Africa & Elephant seals in California
    • In both of these species, individuals are almost genetically identical
    • For the seals, the bottleneck effect was caused to overhunting during the 19th century.
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11
Q

Cell theory

A
  • Cells come from pre-existing cells
  • First cells on Earth came from inorganic chemicals; process of chemical evolution
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12
Q

Charles Darwin

  • Overview
  • Theory
A
  • 1831 went on expedition to South America, the Galapagos Islands on the HMS Beagle
    • Observations about the similarities & differences in species & their adaptations
    • Geological studies
  • Concluded the mechanism of evolution was Natural Selection
  • Theory
    • Compete for available resources
    • Heritable variation
    • Adapt to conditions as the environment changes
    • Differ in terms of their reproductive success
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13
Q

Chemical evolution

A
  • Organic compounds were formed from inorganic ones due to conditions of the primitive earth’s atmosphere
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14
Q

Chordata characteristics

A
  • Notochord
    • A dorsal supporting rod
    • Not a “backbone” but in some chordates, it has been modified to form a backbone
  • Dorsal tubular nerve cord
    • In vertebrates, a spinal cord that is enclosed by vertebra bones
  • Pharyngeal pouches
    • Aquatic chordates: become gills
    • Land chordates: become modified for other functions (ie tonsils in humans)
  • Post anal tail
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15
Q

Chordata subphylas

A
  1. Cephalochordata: small marine invertebrates called lancelets (ie amphioxus)
  2. Urochordata: sessile marine invertebrates (ie sea squirt)
  3. Vertebrata: chordates with a backbone (ie homo sapien)
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16
Q

Classifications (ordered list)

A
  1. Domain: largest, has most members
  2. Kingdom
  3. Phylum
  4. Class
  5. Order
  6. Family
  7. Genus
  8. Species: smallest, is only one type of living thing
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17
Q

Complete classification of humans

A
  • Domain: Eukarya
  • Kingdom: Animal
  • Phylum: Chordata
  • Subphylum: Vertebrata
  • Class: Mammalia
  • Subclass: Eutheria
  • Order: Primates
  • Suborder: Anthropoids
  • Family: Hominid
  • Genus: Homo
  • Species: Sapiens
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18
Q

Conditions of the Earth’s primitive atmosphere

A
  • No oxygen
  • High amount of UV light from sun
  • Constant electrical storms
  • Very high temperature
  • Atmosphere rich in gasses
    • hydrogen (H2)
    • ammonia (NH3)
    • methane (CH4)
    • sulfur (S)
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19
Q

Continental drift

A

The position of the continents has never been fixed. Their positions and the positions of the oceans have changed over time.

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20
Q

Cytochrome C Gene

A
  • The specific gene that can show evolutionary relationships
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21
Q

Difference between the two suborders of primates

A
  • Prosimian
    • Have a partial snout present, a smaller brain, may have claws present, and still retain a relatively good sense of smell
    • Examples: lemurs, loruses, and tarsies
  • Anthropoids
    • Examples: monkeys, apes, and humans
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22
Q

Domains of living things

A
  • There are three domains of living things:
    • Archae: unicellular, prokaryotic, are the most primitive type of living things, and live in harsh aquatic environments
    • Bacteria: unicellular, prokaryotic, and are more advanced than Archae
    • Eukarya: are single or multicelled, eukaryotic, and are the most advanced type of living thing
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23
Q

Eukary Kingdoms & Classification Criteria

A
  • Kingdoms
    • Protista: unicellular, all 3 methods, ~100k, ie amoeba
    • Fungi: multi-celled, ingest or absorb, ~100k
    • Plants: multi-celled, photosynthesis, ~350k
    • Animal: multi-celled, ingest, ~5M
  • Classification criteria
    • Organization: single-celled, multi-celled
    • Obtaining nutrients: absorb, ingest, photosynthesis
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24
Q

Eutheria orders

A
  • Over 20 orders
  • Examples
    • Carnivora: dogs, wolves
    • Primates: humans
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25
Q

Evolution

  • Overview
  • Levels of evolution
A
  • A change in heritable traits within a population over many generations
  • Results in improved adaptation to an environment & new species
  • AKA descent with modification
    • All living things are descended from a common ancestor, but they have become modified to adapt to a certain way of life
    • Example: humans & fish
      • both are descended from a common ancestor, but humans have become adapted for life on land & fish in water
  • Levels of evolution
    • Microevolution: small genetic changes in a species
    • Macroevolution: major changes in life forms due to accumulation of major genetic changes; leads to new species
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26
Q

Evolution evidence

A
  • Anatomical
    • The concept of common descent
    • Explanation for anatomical similarities among organisms
  • Biochemical
    • Similarities in the nucleotide sequence of genes & the amino acid sequence of proteins between living things
  • Biogeography
    • Related forms evolved in one locale and then spread to accessible regions
    • 6 regions; each having characteristic life forms
  • Fossils
    • Remains of past life forms often found embedded in sedimentary rock
    • Show transitional life forms; a link between two groups of organisms
    • Allowed the creation of a geological time scale of Earth, which divides history into eras, periods and epochs
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27
Q

Fitness

A

Measured by the number of fertile offspring produced throughout an organism’s lifetime

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28
Q

Founder effect

A
  • Occurs when a few individuals form a new colony, and only a fraction of the total genetic diversity of the original gene pool is represented in these individuals
  • The particular alleles carried by the founders are dictated by chance alone
  • A founder event is the same as a bottleneck, except that in a founder event, the original population still exists
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29
Q

Gene flow

A
  • Causes a change in allele frequencies due to migration of individuals
  • Mixes genetic diversity and keeps the gene pools of populations similar
  • Example
    • Plants are not able to migrate, but their pollen is often blown by the wind or carried by insects into different populations
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30
Q

Gene pool

A

The alleles of all genes in all individuals in a population

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31
Q

Genetic drift

A
  • A change in allele frequencies due to random chance
  • Natural selection or environmental influences are not involved
  • 2 types
    • Founder effect:
      • allele frequencies change when a new settlement is founded by a small number of individuals
      • the founding population does not have all the alleles possible for the species
    • Bottleneck effect:
      • allele frequencies change when a population is reduced to near extinction
32
Q

Geological Eras

A
  • Precambrian: where life began. This era is not divided into periods. By end of this era, soft bodied invertebrates appeared
  • Paleozoic era: by end of this era, all major groups of animals & plants appeared and land dwellers appeared
  • Mesozoic: known as the “age of reptiles”. Dinosaurs appeared & become extinct by the end of this era. Jurassic period is when dinosaurs flourished. Placental mammals appeared at the end of this era
  • Cenozoic: modern day. Is the only era divided into epochs. Primates appeared here and humans appeared at the end of this era
33
Q

Germ layers

A
  • Only present in animals that have the tissue or organ level of organization
  • Types
    • Diploblastic: have two layers (most primitive)
    • Triploblastic: have three layers (most advanced)
34
Q

Heterozygote advantage

A
  • Only alleles that are expressed (cause a phenotypic difference) are subject to natural selection
  • This makes the heterozygote a potential protector of recessive alleles that might otherwise be weeded out of the gene pool by natural selection
35
Q

How do homologous structures support the theory of evolution?

A
  • Descent from a common ancestor
  • Living things have changed to become adapted to different ways of life
  • Example: forelimbs have a similar structure because the structure was a feature inherited from a common ancestor
36
Q

How do we know the Earth’s primitive atmosphere allowed for the formation of organic molecules?

A
  • Proven by the Miller-Urey experiment
    • Experiment simulated primitive conditions
    • Resulted in small organic molecules being formed
    • Gave rise to the first true cell to be formed, the protocell (prokaryotic cell)
  • Once formed, evolution could take place
37
Q

How does a mutation cause traits to change?

A
  • A change in the nucleotide sequence of a gene may change the…
    • amino acid sequence
    • protein structure
    • protein function
    • traits of an organism
38
Q

How does biochemical evidence support the theory of evolution?

A
  • Shows descent from a common ancestor
  • Sequences are similar because they are descended from a common prokaryotic ancestor
39
Q

How does biogeographical evidence support the theory of evolution?

A
  • Uneven distribution of species around the world
  • Related organisms are found in similar parts of the world. This is because they are all descendants of a common regional ancestor
  • Some species were able to spread to other regions as geography & continental drift predicts
40
Q

How does fossil evidence support the theory of evolution?

A
  • Fossils show that living things have…
    • changed over time (ie horses have changed over time)
    • become more complex (ie older fossils show more primitive life forms while newer fossils show more complex ones)
    • transitional life forms (ie the transitional life form is extinct but the two groups of organisms it links together are not)
41
Q

Human evolution process

A
  • The replacement model:
    • Modern humans originated in Africa
    • After migrating into Europe and Asia they replaced the other homo species (including Neandertals and Denisovans)
42
Q

Individual variation

A

The members of a population differ from one another

43
Q

Jean Baptiste Lamarck

A
  • Proposed the theory of evolution in 1801
  • Mechanism of evolution: Inheritance of Acquired Characteristics
    • Life has changed over time
    • Characteristics of an organism changed through “use” or “disuse”
    • No extinction
44
Q

Macroevolution process

A
  1. Single-celled, prokaryotic organisms that lived in the ocean (Domains: Bacteria & Archae)
  2. Singled celled eukaryotic organisms that lived in the ocean (Kingdom: Protist)
  3. Multicelled eukaryotic organisms that lived in the ocean (Kingdom Fungi & invertebrate animals from the Animal kingdom)
  4. Vertebrate animals appear. Ocean-dwelling, jawless fish
  5. Organisms inhabit land & primitive plants appear. Amphibians, reptiles, & insects
  6. Mammals & birds appear. Reptiles gave rise to both mammals & birds
  7. Primates appear. The common ancestor primates was a “shrew like” creature
  8. Humans appear
45
Q

Mammalia characteristics

A
  • Warm blooded
  • Mammary glands to produce milk
  • Body hair
46
Q

Mammalia subclasses

A
  • Monotremes
    • Features: Egg laying (embryo develops in an egg)
    • Where they evolved: Australia
    • Examples: Only two species; platypus, spiny anteater
  • Marsupials
    • Features: Pouched (embryo develops in a pouch)
    • Where they evolved: Australia
    • Examples: Kangaroo, koala bear
  • Eutheria or Placental
    • Features: Placental (embryo develops in uterus & is nourished by placenta)
    • Where they evolved: Everywhere except Australia
    • Examples: Humans and most other mammals
47
Q

Mass extinctions

A
  • Extinction is the death of every member of a species
  • During mass extinctions, a large percentage of species become extinct within a relatively short period of time
48
Q

Miller Urey experiment

A
  • Experiment that simulated Earth’s primitive atmosphere conditions and resulted in small organic molecules being formed
  • Significant for two reasons
    • Demonstrated that biomolecules can form under ancient Earth-like conditions
    • Transformed speculation that life may have emerged from chemistry into a testable science
  • Led to a new field of research known as prebiotic chemistry
49
Q

Modern Theory of Evolution

  • Differences between modern & Darwin/Lamark theories
  • Mechanisms of genetic change
A
  • Different than Lamark & Darwin’s theories
    • Emphasizes genes
      • The variation in a population is due to different alleles
      • Evolution causes a change in the frequency of alleles in a population
    • Natural selection is not the only mechanism of genetic change
      • Agrees with Darwin’s idea of natural selection, but there are other processes besides natural selection that cause genetic change
  • Mechanisms of genetic change
    • Genetic drift
    • Gene flow
    • Mutations
    • Natural selection
    • Non-random mating
50
Q

Mutations

A
  • A random change in the nucleotide sequence of a gene
  • Since mutations create new alleles, they are the basis for which the other mechanisms in the Modern Theory work
  • “Raw material of evolution“ because mutations cause the variation necessary in a population for evolution to occur
51
Q

Natural selection

A
  • Allows some individuals with an advantage over others to produce more offspring
  • Causes change in allele frequencies due to the environment. The environment determines which alleles are favorable and which are not
  • Modern examples
    • Glucose hating roaches: Bate traps were bated with poisoned glucose. One roach had an aversion to glucose & didn’t take the bait–this roach was more fit. It reproduced more & passed on the gene to hate glucose. Over time, roaches evolved to hate glucose
    • Insecticide resistant bugs
    • Antibiotic-resistant bacteria
52
Q

Natural selection requirements

A
  • Differential reproductive success
  • Individual variation
  • Inheritance
  • Overproduction
53
Q

Natural selection types

A
  • Directional selection
    • When an extreme phenotype is favored and the distribution curve shifts in that direction
    • Can occur when a population is adapting to a changing environment
    • Example: antibiotic resistance
  • Disruptive selection
    • When 2+ extreme phenotypes are favored over any intermediate phenotype
    • Example
    • British land snails (grasslands vs forested areas)
  • Stabilizing selection
    • Extreme phenotypes are selected against, and individuals near the average are favored
    • Can improve adaptation of the population to those aspects of the environment that remain constant
54
Q

Non-random mating

A
  • Individuals are selective about choosing a mate with a preferred trait
  • Because most sexually reproducing organisms select their mates based on some trait, random mating is never observed in natural populations
  • Decreases genetic variation
  • Example: inbreeding
55
Q

Overproduction

A

Individuals in a population are engaged in a struggle for existence because breeding individuals in a population tend to produce more offspring than the environment can support.

56
Q

Phyla classification characteristics

A
  1. Level of organization: cellular, tissue, organs
  2. Digestive system: incomplete, complete
  3. Body cavity: acoelom, pseudocoelom, coelom
  4. Body plan (symmetry): asymmetry, radial, bilateral
  5. Repetition of body parts: not segmented, segmented
57
Q

Phyla divisions (List by segmentation)

A
  • Not segmented
    • Cnidaria
    • Mollusca
    • Nematoda (Roundworms)
    • Platyhelminthes (Flatworms)
    • Porifera
  • Segmented
    • Annelida (Segmented worms)
    • Arthropoda
    • Chordata
    • Echinodermata
58
Q

Phyla divisions (not segmented)

A
59
Q

Phyla divisions (segmented*)

A
60
Q

Point mutation

A
  • Mutations that can cause a malfunctioning protein to be harmful to an organism
  • Called “silent” if it does not result in a change to the function of the protein encoded by the gene
  • A change in a single nucleotide in a gene
61
Q

Population

A
  • All members of a single species that occupy a particular area at the same time and that interbreed and exchange genes
62
Q

Primate characteristics

A
  1. Adapted to an arboreal life
  2. Limbs are mobile** with **5 digits each (allows for grasping ability)
  3. Opposable big toe** and **thumb (allows for grasping ability)
  4. Have nails instead of claws (allows for grasping ability)
  5. A shortened snout which allows for the eyes** to be located to the **front** of the head. This also allows for **stereoscopic vision (able to see in three dimensions and have depth perception) and also binocular vision (able to view an object with both eyes.
  6. A larger** and more **complex brain
  7. They give birth to one offspring at a time
63
Q

Protocell

A
  • Name of the first cell formed by organic molecules
  • It gave rise to the first true cell which was prokaryotic
  • Once the true cell formed, evolution could take place
64
Q

Punctuated equilibrium model

A
  • States that long periods of stasis, or no visible change, are followed by rapid periods of speciation
  • Speciation often occurs relatively rapidly, and this can explain why few transitional links are found. Mass extinction events are often followed by rapid periods of speciation
65
Q

Speciation

  • Description
  • Types
A
  • When one species gives rise to two species, each of which continues on its own evolutionary pathway
  • Occurs whenever reproductive isolation develops between two formerly interbreeding groups or population
  • Types
    • Allopatric speciation
      • Occurs when populations become separated by a geographic barrier and gene flow is no longer possible
      • Example: Salamanders in California
    • Sympatric speciation
      • Found among plants, where the multiplication of the chromosome number in one plant prevents it from successfully reproducing with others of its kind
      • Self-reproduction can maintain such a new plant species
66
Q

Species

A
  • A group of organisms capable of interbreeding that are isolated reproductively from other organisms
  • If organisms cannot mate and produce offspring in nature, or if their offspring are sterile, they are defined as different species
67
Q

Taxonomy

A
  • Placing organisms into categories
  • Categories show
    1. Similarities between organisms
    2. Differences between organisms
    3. Evolutionary relationships
  • Taxons = general name for organisms that exhibit a set of shared traits
68
Q

Theory of Evolution

A
  • All living things are descended from a common ancestor, thus they are all related
  • Organisms have changed over time to become better adapted to their environment or way of life
  • Evolution produces more complex, better adapted organisms
  • If a species cannot adapt, it becomes extinct
69
Q

Trait

A

An inherited characteristic. Can be physical or physiological.

70
Q

Type of skeleton

A
  • Not used to classify phyla
  • Types
    • Hydrostatic (most primitive): a skeleton based on the pressure of fluid in the organisms body
    • Exoskeleton: a skeleton on the outside of the body (externally)
    • Endoskeleton (most advanced): a skeleton made of cartilage and/or bone located internally
71
Q

Vertebrata classes

A
  • Agnatha (jawless fish)
  • Amphibia
  • Aves (birds)
  • Cephalochordata (lancelets)
  • Chondrichthyes (cartilaginous fish)
  • Mammalia
  • Osteichthyes (bony fish)
  • Reptilia
  • Urochordata (tunicates)
72
Q

Vestigial structures

A
  • Anatomical features that are fully developed in one group of organisms but that are reduced and may have no function in similar groups
  • Occur because organisms inherit their anatomy from their ancestors
  • Example
    • Most birds have wings for flight, but ostriches have greatly reduced wings and cannot fly
73
Q

What happens as a result of the genetic changes?

A
  • Organisms become better adapted to their environment or way of life
  • New species develop
74
Q

What types of changes occur in evolution?

A
  • Genes & alleles
75
Q

What types of organisms evolve?

A
  • Individual organisms do not evolve
  • Populations of organisms evolve

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