Chippy Definitions Flashcards
1
Q
Evolution
A
Idea that living species are descendants of ancestral species that were different from the present-day ones
As the change in the genetic composition of a population from generation to generation
2
Q
Adaptation
A
Inherited characteristic of an organism that enhances its survival and reproduction in a specific environment
3
Q
Natural Selection
A
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits
4
Q
Artificial Selection
A
The selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits
5
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Darwin Observations
A
- Members of a population often varying their inherited traits
- All species can produce more offspring than their environment can support and many of these offspring fail to survive and reproduce
6
Q
Darwin Inferences
A
- Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals
- The unequal ability of individuals to survive and reproduce will lead to the accumulation of favourable traits in the population over generations
7
Q
Homology
A
Similarity in characteristics resulting from a shared ancestry
8
Q
Convergent Evolution
A
The evolution of similar features in independent evolutionary lineages
9
Q
Analogous
A
Having characteristics that are similar because of convergent evolution NOT homology
• Convergent evolution
10
Q
Endemic
A
A species that is confined to a specific geographic area
11
Q
Microevolution
A
– Evolutionary change below the species level Change in allele frequencies in a population over generations
12
Q
Neutral Variation
A
Genetic variation that does not provide a selective advantage or disadvantage
13
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Genetic Variation
A
Differences among individuals in the composition of their genes or other DNA segments
14
Q
Gene Pool
A
Aggregate of all copies of every type of allele at all loci in every individual in a population
15
Q
Hardy-Weinberg Equilib
A
The state of a population in which frequencies of alleles and genotypes remain constant from generation to generation
• Test if evolution has occurred = Significantly difference
16
Q
Hardy-Weinberg Equilib 5 conditions
A
- NO mutations
- Random mating
- NO natural selection
- Extremely large population
- NO gene flow
17
Q
Genetic Drift
A
A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next (Small populations)
• Significant in small populations
• Can cause allele frequencies to change at random
• Can lead to loss of genetic variation within populations
• Can cause harmful alleles to become fixed
18
Q
Founder Effect
A
Genetic drift that occurs when a few individuals become isolated from larger population and form a new population whose gene pool composition is not reflective of that of the original population
19
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Bottleneck Effect
A
Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions Typically the surviving population is no longer genetically representative of the original population
20
Q
Gene Flow
A
The transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes
21
Q
Relative Fitness
A
The combination an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population
22
Q
Directional Selection
A
Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than others go
• Conditions favour an individual
23
Q
Disruptive Selection
A
Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes
• Conditions favour both extremes
24
Q
Stabilizing Selection
A
Natural selection in which intermediate phenotypes survive or reproduce more successfully then do extreme phenotypes
• Acts against both extremes and favours intermediate variants
25
Sexual Dimorphism
Differences between the secondary sex characteristics of males and females
• Differences in size, colour, ornamentation, and behaviour
26
Intrasexual Selection
Selection in which there is direct competition among individuals of one sex for mates of the opposite sex
27
Intersexual Selection
Mate Choice) Selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex
• Seeking attractive mates
28
Balancing Selection
Natural Selection that maintains two or more phenotypic forms in a population
• Includes heterozygote advantage and frequency-dependent selection
29
Heterozygote Advantage
Greater reproductive success of heterozygous individuals compared with homozygotes; tends to preserve variation in the gene pool
• IN TERMS OF GENOTYPE
30
Frequency Dependent Selection
Selection in which the fitness of a phenotype depends on how common the phenotype is in the population
31
Fixed Action Pattern
A sequence of unlearned acts that is essentially unchangeable and once initiated usually carried to completion
• Territorial response
• Seen in Male sticklebacks
32
Sign Stimulus
An external sensory cue that triggers a fixed action pattern by an animal
33
Migration
A regular, long-distance change in location
• Geese!
• Behavioural Rhythms – A daily cycle of rest and activity
• Circadian clock is synchronized with light and dark cycles of the environment
34
Signal Communication
In animal behaviour, transmission of stimulus from one animal to another
• Communication in cell-to-cell communication in all multicellular organisms
• Ex. Fruit fly courtship
• Ex. Bees communicating location of food through dance
35
Pheromones
In animals and fungi, a small molecule released into the environment that functions in communication between members of the same species
• Ex. Hormone
36
Foraging
Seeking and obtaining food
• Optimal foraging model = Feeding costs vs feeding benefits
o Minimize costs and maximize benefits = Forager becomes a likely meal for the predator
• BIG Cost = Predation
37
Promiscuous
Relationship in which mating occurs with no strong pair bonds or lasting relationship
38
Monogamous
Relationship type in which one male mates with just one female
39
Polygamous
Relationship type in which an individual of one sex mates with several fo the other
40
Mate Choice Copying
Individuals in a population copy the mate choice of others
• Result of social learning
• Observed in fish and birds
• Ex. Female guppies always choose the male with more orange colouration
41
Cooperation
Mutualistic interaction with fitness benefits to all parties
42
Altrusim
One party sacrifices fitness for other's benefits
43
Selfishness
One party takes at the expense of others
44
Spite
Behaviour that results in fitness loss to all parties
45
Alarm Calling
• Belding’s groundsquirrels practice sentry duty in their “prairie dog towns”
o Place themselves at greater risk of predation when they warn of threats
• Females are more likely to call when close kin and near (Many close family members)
• Females form coops to chase out intruding squirrels (Mother, sister, and daughter tema up)
46
Population Ecology
Study of populations in relation to their environment, including environmental influences on population density and distribution, age structures, and variations in population size
47
Density
The number of individuals per unit area volume
48
Dispersion
The pattern of spacing among individuals within the boundaries of a population
49
Mark recapture method
Sampling technique used to estimate animal populations
50
Immigration
Influx of new individuals into a population from other areas
51
Emigration
The movement of individuals out of the population
52
Territoriality
Uniform) A behaviour where an animal defends a bounded physical space against encroachment by other individuals
53
Survivorship Curve: Type l
Is flat, reflecting low death rates during early and middle life and then drops steeply as death rates increase among older age groups
o Large mammals and humans
54
Survivorship Curve: Type lll
Drops sharply at the start = high death rates for young, then flattens out as death rates decline for those few individuals that survive the early period of die-off
o Organisms that produce very large numbers of offspring and provide little to no care Long-live plants, fishes, most marine invertebrates
55
Survivorship Curve: Type ll
Are intermediate, with a constant death rate over the organism’s life span
o Belding’s groundsquirrels and other rodents and some lizards and annual plants
56
Exponential Population Growth
Growth of a population in an ideal unlimited environment represented by a J sharped curve when population size is plotted over time
• Is a characteristic of some populations that are introduced into a new environment or whose number have been drastically reduced by a catastrophic event and are rebounding
57
Carrying Capacity
(K) Maximum population size that can be supported by the available resources
58
Logistic Population Growth
Population growth that levels off as population size approaches carrying capacity S shape of populations of small animals
59
Semelparity
Reproduction in which an organism produces all of its offspring in a single event (Big Bang reproduction)
60
Iteroparity
Reproduction in which adults produce offspring over many years
61
K-Selection
Selection for life history traits that are sensitive to population density and are favoured at high densities Density dependent selection
62
r- Selection
Selection for traits that maximize reproductive success in uncrowded environments Density independent selection
63
Ecological Niche
Sum of a species’ use of the biotic and abiotic resources in its environment
• Ex. Niche of tropical tree lizard could be the temperature range it tolerates
64
Resource Partitioning
Division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species
65
Fundamental Niche
The ecological space occupied by a species when there are not any competitors in that species’ habitat
66
Realized Niche
The ecological space occupied by a species when the species’ competitors are present
67
Aposematic Colouration
Bright warning colouration of many animals with effective physical or chemical defences
68
Cryptic Colouration
Camouflage that makes a potential prey difficult to spot against its background
69
Batesian Mimicry
Mimicry where a harmless species looks like a species that is poisonous or otherwise harmful to predators
70
Mulleriam Mimicry
Reciprocal mimicry by two unpalatable (harmful) species
71
Symbiosis
An ecological relationship between organisms of two different species that live together in direct and intimate contact
72
Parasitism
Symbiotic relationship where the parasite benefits at the expense of another organism by living within (endo) or on (ecto) the host
73
Mutualism
An ecological interaction that benefits each of the interacting species
74
Commensalism
A symbiotic relationship in which one organism benefits but other is neither helped or harmed
75
Facilitation
An interaction where one species has a positive effect on the survival and reproduction of another species without the intimate association of symbiosis
76
Species Composition
The number and variety of species that make up a community
77
Species Richness
Number of specie present in a community
78
Energetic Hypothesis
Concept that the length of food chain is limited by the inefficiency of energy transfer along the chain
79
Keystone Species
Not necessarily an abundant species in the community yet BUT exerts strong control on the community structure but its ecological role or niche
80
Bottom up Control
Mineral nutrients influence community organization by controlling plant and phytoplankton numbers which control herbivore numbers which control predator numbers
81
Top down Control
redation influences community organization by controlling herbivore numbers which control plant or phytoplankton numbers which controls nutrient levels
82
Intermediate Disturbance Hypothesis
Concept that moderate levels of disturbance can foster greater species diversity than low or high levels of disturbance
83
Ecological Succesion
Species composition of a community following a disturbance
84
Primary Succession
Occurs in an area where there were original no organisms present and not even soil formed yet
85
Secondary Succession
Type of succession that occurs where an existing community has eben cleared by some disturbance that leaves the soil
86
Speciation
An evolutionary process in which one species splits into two or more species.
- Responsibly for the diversity of life yielding new species that differ from existing one
87
Macroevolution
evolutionary changes above the species level.
- Example origin of a new group of organisms through a species of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery
88
Biological Species Concept
definition of a species as a group of populations whose members have the potential to interbreed in nature and produce, viable, fertile offspring w/ members of other such groups
- Emphasises separateness of species from one another due to reproductive barriers
89
Species
a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.
90
What holds the gene pool of a species together, causing its members to resemble each other more than they resemble other species?
Gene flow: the transfer of alleles between populations; absence plays a key role in the formation of new species, as well as in keeping them apart once their potential to interbreed has been reduced.
91
Reproductive Isolation
the existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.
- Influenced by relatively small amounts of genes
92
Hybrid
Offspring that results from the mating of individuals from two different species or from two true-breeding varieties of the same species.
- Reproductive barriers limit the formation of hybrids
- Often less fit than members of parent species
93
Prezygotic Barriers
a reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted.
94
Postzygotic Barriers
a reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults.
95
Morphological Species Concept
Morphological Species Concept: a definition of species in terms of measurable anatomical criteria.
96
Ecological Species Concept
a definition of species in term of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment.
97
Phylogenetic Species Concept
definition of species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life.
- Trace phylogenetic history of a species by comparing its characteristics (morphology or molecular sequences) with those of other organisms
98
Allopatric Speciation
formation of new species in population that are geographically isolated from one another; restrict gene flow
- Importance is suggested by the fact that regions that are isolated or highly subdivided by barriers typically have more species
99
Sympatric Speciation
formation of new species in populations that live in the same geographic area; reproductive barrier that isolates a subset of a population from the remainder of the population in the same area
- Can also occur when genetic factors enable a subpopulation to exploit a habitat or resource not used by the parent population
- Evidence that it can be driven by sexual selection
100
Polyploidy
a chromosomal alteration in which the organism possesses more than two complete chromosome sets; result of an accident of cell division.
- More common in plants, but can happen in animals
101
Autopolyploid
an individual that has more than two chromosome sets that are sets that are all derived from a single species.
- EXAMPLE: in plants a failure of cell division could double a cell’s chromosome number from the diploid number (2n) to a tetraploid number (4n).
102
Allopolyploid
a fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes.
103
Hybrid Zone
a geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry.
- Infer that there is an obstacle to gene flow why there is a pattern of allele frequencies across a hybrid zone
- Wherever habitats of the interbreeding species meet
104
Reinforcement
a process in which natural selection strengthens prezygotic barriers to reproduction, thus reducing the chances of hybrid formation
- Likely to occur only if hybrid offspring are less fit than members of the parent species
105
How did the first living cells appear?
Hypothesised that chemical and physical processes on early Earth, sided by the emerging force of natural selection, could have produced very simple cells through a sequence of 4 main stages:
1. The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nitrogenous bases
2. The joining of these small molecules into macromolecules, such as proteins and nucleic acids
3. The packaging of these molecules into protocells: abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings
4. The origin of self-replicating molecules that eventually made inheritance possible
Protocells:
- All organisms must be able to carry out both reproduction and energy processing (metabolism)
- DNA replication requires elaborate enzymatic machinery along with an abundant supply of nucleotide building blocks provided by the cell’s metabolism
o Suggests that self-replicating molecules and a metabolism-like source of building blocks may have appeared together in early protocells
- Abiotically produced vesicles can exhibit certain properties of life
o Vesicles can form spontaneously when lipids or other organic molecules are added to water
106
Stromatolites
Layered rock that results from the activities of prokaryotes that bind thin films of sediment together
107
Oxygen Revolution
enormous impact on life
| - Rising concentration of atmospheric O2 probably doomed many prokaryotic groups
108
Endosymbiont Theory
theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell; engulfed cell and its host cell then evolved into a single organism
109
Cambrian Explosion
relatively brief time in geologic history when many present-day phyla of animals first appeared in the fossil record; saw the emergence of the first large, hard-bodied animals
110
Plate Tectonics
the theory that the continents are part of great plates of Earth’s crust that float on the hot, underlying portion of the mantle; movements in the mantle cause the continents to move slowly over time
111
Continental Drift
movements in the mantle cause the plates to move over time
112
Pangaea
the supercontinent that formed near the end of the Paleozoic era, when plate movements brought all the landmasses of Earth together.
113
Adaptive Radiation
period of evolutionary change in which groups of organisms form many new species whose adaptions allow them to fill different ecological roles in their communities.
- Large scale ones occurred after each of the 5 mass extinctions
114
Heterochrony
evolutionary change in the timing or rate of an organism’s development
- EX/ skull of chimp vs. human
- Can also alter the timing of reproductive development relative to the development of non-reproductive organs
- Paedomophosis: retention in an adult organism of the juvenile features of its evolutionary ancestors
115
Sexual Reproduction
fusion of haploid gametes forms a diploid cell, the zygote
116
Asexual Reproduction
generation of new individuals w/out the fusion of egg and sperm entirely of mitotic division
117
Fission
separation of an organism into two or more individuals of approximately equal size
118
Budding
sexual reproduction in which outgrowths from the parent form and pinch off to live independently or else remain attached to eventually form extensive colonies
119
Fragmentation
individual may disintegrate into many small pieces, each of which regenerated into many small pieces
120
Parthenogenesis
asexual reproduction where an egg develops without being fertilize by a sperm.
121
Hermaphroditism
a condition in which an individual has both female and male gonads and functions as both a male and female in sexual reproduction by producing both sperm and eggs.
122
Fertilization
the union of haploid gametes to produce a diploid zygote
123
External Fertilization
fusion of gametes that parents have discharged into environment.
124
Internal Fertilization
fusion of eggs and sperm within the female reproductive tract; sperm are typically deposited in or near the tract
