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Flashcards in Evolution Deck (73):
1

Species vary locally

Closely related but different species occupying different habitat in same geographic area

2

Evolutionary theory explains existence of

Homologous structures adapted to different purposes as the result of descent with modification

3

Evidence of common descent

Universal genetic code
Homologous molecules

4

Grants

Documented that natural selection in Galapagos finches takes place frequently
Variation within a species increases the likelihood of the species adapting to and surging environmental change

5

Variation

Raw material for natural selection

6

Techniques of molecular genetics used

To form and test hypotheses about heritable variation and natural selection

7

Natural selection never acts on

Genes because the entire organism either survives or doesn't

8

Allele frequency has nothing to do with

Dominant and recessive

9

3 sources of genetic variation

Mutation
Genetic recombination
Lateral gene transfer

10

We are born with

Approx 300 mutations
Most heritable mutations come from genetic recombination

11

Independent assortment in humans results in

8.4 million gene combinations

12

Lateral gene transfer

Passing of genes from one organism to another that is not its offspring
Important in evolution of antibiotic resistance in bacteria

13

Number of phenotype a for trait depends on

Number of genes that control it
Single gene trait- 1-3 phenotypes
Polygenic trait- many possible genotype and even more phenotypes (bell shaped curve = normal distribution)

14

Phenotypic ratios determined by

Frequency of alleles and whether alleles are dominant or recessive

15

Evolutionary fitness

Success in passing genes to next generation

16

Evolutionary adaptation

Any genetically controlled trait that increases an individuals ability to pass along its alleles

17

Natural selection on single gene trait

Change in allele and phenotype frequencies

18

Natural selection on polygenic trait

Affect relative fitness if phenotypes and can result in
Disruptive selection
Directional selection
Stabilizing selection

19

Genetic drift

Random change in allele frequency
Bottleneck effect
Founder effect

20

Meiosis and fertilization by themselves don't change

Allele frequencies

21

Hardy Weinberg principle

(Frequency of AA) + (frequency of Aa) + (frequency of aa) = 100% and
(Frequency of A) + (frequency of a) = 1
Genetic equilibrium

22

Conditions that disrupt genetic equilibrium

No random mating
Small population size
Immigration or emigration
Mutations
Natural selection
Shuffling of genes altering frequencies of alleles

23

Species

Population or group of populations whose members can interbreed and produce fertile offspring

24

Speciation in Galapagos finches

Founding of new populations
Geographic isolation
Changes in new populations gene pool
Behavioral isolation
Ecological competition
Repetition

25

Molecular clock

Uses mutation rates in DNA to estimate that 2 species have been evolving independently

26

Neutral mutations

No effect on phenotype
Accumulate in DNA of different species at about the same rate

27

More differences between DNA of two species...

More time passed since they shared a common ancestor

28

Many different clocks which allow researchers to...

Time evolutionary events
Accuracy checked by trying to estimate how often mutations occur b

29

New genes can evolve through

Duplication and modification of existing genes

30

Homologous chromosomes exchange DNA during

Crossing over
sometimes involves unequal swapping of DNA so one chromosome gets extra DNA varying from part of a gene or a full gene to a longer length of chromosome)

31

Extra copies of a gene can undergo

Mutations that change their function
The original gene remains and is not affected
Multiple copies of a duplicated gene can turn into a group of related genes called a gene family (produced similar proteins)

32

Hox genes

Embryo development and size and shape of structures
Small changes in activity during embryo logical development can produce large changes

33

Species vary globally

Seemingly similar but unrelated species living in ecologically similar environments

34

Early scientific names

Extremely long
Difficult to standardize

35

Linnaeus

Developed binomial nomenclature
2nd part of scientific name is unique to each organism

36

Systematics

Naming and grouping organisms
Goal is to organize living things into group (taxa) with biological meaning

37

Linnaean classification system

Developed over ime into:
Species, genus, family, order, class, phylum, kingdom
Strategy was based on similarities and differences which causes issues

38

Phylogeny

The evolutionary history of lineages
Goal of phylogenetic systematics- to group species to reflect lines of evolutionary descent

39

Larger tax on

Farther back in time members shared a common ancestor

40

Clade

Group of species that includes one common ancestor and all descendants
Must be mono phyletic

41

Cladistic analysis

Compared traits to determine order groups of organisms branches off from common ancestors

42

Systematists cause about using absence of a trait in analyses because

Distantly related groups can lose same trait

43

Similarities and differences in DNA can be used to

Develop hypotheses about evolutionary relationships
Makes evolutionary trees more accurate
Used when anatomical traits can't provide enough evidence

44

How kingdoms changes

Plantae and animalia to
Monera Protista fungi plantae and animalia to
Eubacteria archaebacteria Protista fungi plantae animalia

45

Domain

Larger more inclusive category than kingdom
Bacteria
Archae
Eukarya

46

Domain bacteria

Unicellular
Prokaryotic
Thick rigid walls with peptidoglycan and cell membrane
Ecologically diverse
Corresponds to kingdom eubacteria

47

Domain archaea

Unicellular
Prokaryotic
Live in extreme environments
Many survive only in absence of oxygen
Cell membranes of unusual lipids
Kingdom archaebacteria

48

Domain Eukarya

All organisms with nucleus
Contains "Protista" plantae and animalia

49

Protista

Unicellular eukaryotes
Brown algae is multicellular

50

Fungi

Heterotrophs
Cell walls with chitin
Feed on dead decaying organism
Secrete digestive enzymes into food source and absorb molecules broken down from enzymes
Some are multicellular

51

Plantae

Autotrophs
Cell walls with cellulose
Photosynthesis through chlorophyll
Nonmotile
Sister group to red algae

52

Animalia

Multicellular
Heterotrophic
No cell walls
Most can move
Diverse

53

Carbon14

Limited to organisms that lived in last 60,000 years
Half life of 5730 years

54

Half life

Time required for half radioactive atoms in a sample to decay

55

Length of half lives and uses

Elements with short half lives- recent fossils
Long Half lives- older fossils

56

Geologic time scale

Time line of earths history
Eons
Eras
Periods

57

More than 99% Of all species that lives on earth are now

Extinct

58

Macro evolutionary patterns

Grand transformations in anatomy, Phylogeny, Ecology, and Behavior, which take place in clashes larger than one species

59

Classification of fossils needed to

Learn about macro evolutionary patterns

60

Environmental conditions change

Processes of evolutionary change enable some species to adapt and thrive
Some Clades are successful because of species diversity

61

Species diversity

Raw material for macro evolutionary change within Clades

62

Background extinction

Species become extinct because of slow process of natural selection

63

Gradualism

Evolution being slow and steady

64

Punctuated equilibrium

Equilibrium that is interrupted by brief periods of rapid change

65

Rapid evolution may occur after

A small population becomes isolated from main population

66

Adaptive radiation

Process by which single species or small group evolves "rapidly" into several different forms that live in different ways

67

Convergent evolution

Produced similar structures or characteristics in distantly related organisms (e. g. Mammals that feed on ants)

68

Co evolution

Process by which two species evolve in response to changes in each other over time

69

Earths early atmosphere

Little or no oxygen
Composed of carbon dioxide, water vapor, nitrogen, carbon monoxide, hydrogen sulfide and cyanide
Oceans brown because of iron

70

RNA world hypothesis

RNA existed before DNA
Steps led to DNA directed protein synthesis

71

Microspheres

Some characteristics of living systems

72

Photosynthetic bacteria

Added oxygen to atmosphere
Oxygen and iron in oceans lead to rust that sank and changed ocean color
Color of sky changed

73

Endosymbiotic theory

Symbiotic relationship evolved over time between primitive eukaryotic cells and prokaryotic cells within them
Prokaryotic cells evolved into mitochondria and chloroplasts