Biol Exam 2

Front 1

Purifying Selection Hypothesis

Back 1

Natural selection against deleterious alleles

Front 2

Purifying selection with asexual organisms

Back 2

may have alleles beneficial and some not, all offspring are clones of their parents so they get the good and the bad no matter what >> selection on genes can act on bad genes and get rid of them for a population with higher fitness

Front 3

changing environment hypothesis

Back 3

offspring that are genetic clones of their parents are unlikely to thrive if the environment changes >> if offspring have various alleles then 1 is bound to survive in the new environment

Front 4

the Modern Synthesis

Back 4

body of work that united the ideas from several biological specialties and which forms logical account of evolution >> reconciles the early genetic studies

Front 5

Darwin's Postulates (1)

Back 5

result of mutation creating new alleles, segregation, independent assortment and cross over shuffling alleles into new combinations

Front 6

Darwin's Postulates (2)

Back 6

individuals pass alleles to offspring in tact within populations are variable for many individuals

Front 7

Darwin's Postulates (3)

Back 7

every generation some individuals are more successful at surviving and reproducing than others

Front 8

Darwin's Postulates (4)

Back 8

individual that survives and reproduces or reproduces most are those with the alleles or allelic combinations that best adapt them to their environment

Front 9

what is evolution?

Back 9

change in population's allele frequencies over time >> outcome is alleles assocaited with higher fitness increase from one generation to the next

certain alleles in associated with favored phenotypes increase in frequency while other alleles decrease in frequency

Front 10

What is the difference between natural selection and evolution pertaining to phenotypes?

Back 10

Natural selection acts on phenotypes in INDIVIDUALS and evolutionary changes occur in populations

Front 11

Population thinking

Back 11

not predicting the frequency of genotypes from a particular mating we need to predict frequency of genotypes and alleles from many thousands of matings in a population

Front 12

Mechanisms of Evolutionary Change: Natural Selection

Back 12

1) Natural Selection >> increase the frequency of certain alleles the ones that contribute to success in survival and reproduction in a certain environment

Front 13

Mechanisms of Evolutionary Change: Mutation

Back 13

modifies allele frequencies by continually introducing new alleles

Front 14

Mechanisms of Evolutionary Change: Gene Flow

Back 14

Migration: when individuals leave on population join another and breed. Allele frequency may change when gene flow occurs because arriving individuals introduce new alleles to the population and departing individuals take alleles from old population

Front 15

Mechanisms of Evolutionary Change: Genetic Drift

Back 15

cause allele frequencies to inchange randomly, some cases of drift even cause alleels taht decrease fitness to increase in frequency >>
sampling error

Front 16

Which mechanism results in adaptation and increased fitness?

Back 16

natural selection

Front 17

Gene Pool

Back 17

all of the gametes produced in each generation go into a single group called the gene pool and then combine at random to form offspring >> compare pool of parents and offspring if evolution didn't occur pools should be identical

Front 18

Hardy Weinberg Equilibrium

Back 18

when 4 evolutionary forces are not acting mating is random and allele frequency is same between parental offspring genes = no evolution has occurred

>> Null hypothesis : because saying that evolution is not occurring nothing is happening (if identical)

Front 19

Hardy Weinberg Principle and proportion

Back 19

prediction of allele frequencies of an entire population if true should have these proportions >>

A1A1 = p
A2A2 = q
A1A2 = pq

p^2 , 2pq, q^2

Front 20

HW Assumptions

Back 20

No natural selection

No genetic drift or random allele frequency changes >> assume draw alleles in exact frequencies and not different values

no gene flow >> no new alleles added by immigration lost through emigration (all alleles of offspring population came from original population gene pool)

no mutation

random mating (pick gametes from gene pool at random)

Front 21

Why is HW used as a null hypothesis?

Back 21

predicts no differences among the treatment groups in an experiment

gives allele frequencies if none of the evo. forces are acting

Front 22

What hypothesis does the HW Principle test?

Back 22

That there is currently no evolution occurring at a particular gene and that previous generation mating was random with respect to the gene in question

Front 23

Quantitative Variation

Back 23

categories that are numerical

Front 24

When does Natural selection occur?

Back 24

when individuals with certain phenotypes produce more offspring than individuals with other phenotypes do (heritable variation leads to differenctial success in survival and reproduction)

Front 25

Balancing selection

Back 25

no single allele has distinct advantage and increases in frequency instead there is a balance among several alleles

Front 26

Heterozygote advantage

Back 26

hetero individuals have higher fitness than homozygous individuals because genetic variation maintains populations

Front 27

frequency dependent selection

Back 27

certain alleles favored when they're rare but not when common

>> Genetic variance is increased or maintained

Front 28

Lack of Genetic Variation

Back 28

bad thing because leads to alleels being present that have high fitness under new conditions and this leads to an average fitness decline

Front 29

directional selection

Back 29

avg phenotype of populations changed in one direction,
tends to REDUCE genetic variation
favored alleles eventually reach fixed frequency of 1.0 and unfavored disadvantageous alleles reach a lost frequency of 0.0 (NOT always fixation or loss) sooo allele frequency change and overall variation does become normally distributed because of other mechanisms (inde. assrtmt, mutation, recomb. create genetic variation)

Front 30

stabilizing selection

Back 30

reduction of both extremes (lower fitness) and individuals in the middle have higher fitness
>> reduces variation and favors average phenotype over extremes

Front 31

disruptive selection

Back 31

both sides are favored and average has a lower fitness
>> increases variation and favors both extremes selection against average
can cause speciation because selection can result in 2 distinct populations

Front 32

Constraints of EVO: Fitness Trade offs/ countervailing selection

Back 32

inevitable compromises in terms of how those traits perform in the environment >> due to:
-limited resources
-design constraints can't optimize everything

Front 33

Historical Constraints of EVO:

Back 33

all traits have evolved from previously existing traits and SELECTION acts on preexisting traits

Front 34

Evolution is NOT Goal Directed or Progressive

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-adaptations don't occur because organisms want or need them
- natural selection is non progressive (not bigger and better) >> favors individuals that happen to be better adapted to the environment existing at a time
- under evo by n.s. no such thing as HIGHER or LOWER organisms (each is well adapted to their environment)

Front 35

Good of the species

Back 35

organisms don't do things for the good of the species
>> individuals with self sacrificing genes DIE and don't produce offspring
>> individuals with selfish cheater genes SURVIVE and produce offspring sooo
>>> selfish genes increase in frequency while self sacrificing genes decrease in frequency

Front 36

Are all traits adaptive?

Back 36

NO. vestigial traits are not adaptive and evolution by natural selection does not lead to perfection.

Front 37

Genetic Constraints of Evolution

Back 37

genetic correlations occur because of pleiotropy (single allele affects multiple traits)
- lack of genetic variation

Front 38

Acclimation

Back 38

changes in an individuals phenotype that occur in response to changes in environmental conditions

>> PHENOTYPIC changes are not passed on to offspring because no alleles changed in composition

Front 39

Evolutionary Force

Back 39

a process that changes allele frequency

Mutation
Genetic Drift
Gene Flow
Natural Selection

Front 40

Mutation

Back 40

exposure to mutagens can cause mutations in DNA sequence (any changes in an organisms genome) >> these are chance events that create new alleles
- and mistakes that occur as chromosomes are being copied prior to mitosis/ meiosis (meiosis shuffles existing alleles into new combinations
-alleles can be deleterious beneficial or neutral
>> when combined with natural selection it becomes an important evolutionary mechanism
>>> alone it is inconsequential in changing allele frequency at a particular gene
-ULTIMATE source of heritable variation making EVO possible (w/o it there would be no variation)
-only way to introduce new variation to a whole species
(slow process)

Front 41

Genetic Drift

Back 41

random changes in allele frequency due to chance variation in reproductive success among individuals and random sampling error
>> causes allele frequency to drift up and down randomly (LUCK) = fixation and loss of alleles
>> directed by environment and results in adaptation
>> can lead to loss of genetic diversity

Front 42

genetic drift significance in small populations

Back 42

smaller population larger sampling error because you can see in small populations when there is a random sampling error

Front 43

sampling error

Back 43

when drift occurs and allele frequencies change due to blind luck

Front 44

Population Bottleneck/ Genetic Bottleneck

Back 44

sudden reduction in the number of alleels in a population
>> due to disease outbreaks natural catastrophes >> causes bottleneck = luck for those that survive

Front 45

how is genetic drift traced in the lab?

Back 45

with genetic markers: locus' can be identified and traced in populations by lab techniques or by a distinctive visible phenotype

Front 46

Founder Effect

Back 46

change in allele frequencies when a group of individuals emigrate to a new geographic area and establish a new population
>> if group is small enough allele frequency in new population is most guaranteed to be different from those in the source population due to sampling error

Front 47

founder effect

Back 47

follows a founder event in which allele frequencies change by process of genetic drift

Front 48

Consequences of drift with respect to >>
fitness
genetic variation
endangered species

Back 48

fitness: drift is random (non adaptive evolution, its just luck)

genetic variation: drift reduces overall variation (eliminates alleles)

endangered species: drift reduces variation and can even eliminate beneficial alleles by chance

Front 49

Gene Flow

Back 49

movement of alleles from one population to another
THEORY: is one way movement from large population on a continent to a small population on an island

EVO occurs because there is a change in allele frequency

>> homogenizes allele frequencies among populations so reduces genetic differences

>> neutral and random with respect to fitness (may introduce alleles that are adaptive or nonadaptive)

Front 50

gene flow and humans

Back 50

homogenizes humans because migration of individuals from mainland to islands prevents the divergence of the two populations = more homogeneous

Front 51

reduced gene flow

Back 51

populations become more distinct because mutation selection and drift act independently of each other

Front 52

Inbreeding

Back 52

mating between relatives
>> share alleles from recent common ancestor = increases homozygosity so frequency of homozygotes increase and decrease of hetero.
- all recessive alleles hidden in hetero are revealed with so many homo.

>> doesn't cause EVO because allele frequencies don't change in pop as a whole

>> changes genotype frequencies (violates HW Principle) = excess in homozygotes = higher selection acting on genes

increases the rate of purifying selection and eliminates deleterious recessive alleles from a population

Front 53

Inbreeding depression

Back 53

decline in avg fitness that takes place when homozygosity increases and hetero. decreases

deleterious recessives are usually at low frequency most are found in hetero. (no selection against them)

>> makes selection against deleterious recessives more efficient

Front 54

Offspring of inbred matings

Back 54

are expected to have lower fitness because of homozygosity (decreases variation of alleles .. change in environment = death etc.)

Front 55

phylogeny

Back 55

evolutionary history of a clade

shows ancestors and desendant relationsjips among populations or species

put together by observing a species morphological and genetic characteristics

Front 56

clade (lineage)

Back 56

monophyletic group : common ancestor and all its descendants

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monophyletic group

Back 57

common ancestor and all its descendants

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phylogenetic tree

Back 58

graphical summary of that history

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tip

Back 59

taxon terminal node endpoint of a branch represents a group living today or one that ended in extinction

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root

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bas of the tree = most ancestral species

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branch

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represents a population through time

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node

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speciation event

point where two branches diverge and ancestral group splits into two or more descendant groups

Front 63

phenetic approach

Back 63

based on computing a statistic that summarizes overall similarity among populations based on data

no attempt to resolve phylogeny (numerical only)

Front 64

cladistic approach

Back 64

based on realization that relationships among species can be reconstructed by identifying synapomorphies in the species and parsimonys

Front 65

synapomorphy

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shared derived trait found in two or more taxa present in their most common ancestor but is meaning more descent relationships
homologous traits that certain species have that no one else has

allows biologists to recognize monophyletic groups (clades/lineages)

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parsimony

Back 66

implies the least amount of change

Front 67

paraphyletic group

Back 67

ancestor and some but not all descendants

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outgroup

Back 68

species closely related to a group in question but not part of that group, taxonomic group known to have diverged prior to the rest of the taxa in a study

Front 69

homologous traits

Back 69

characteristics that are similar because of descent from a common ancestor

used as evidence for evolution

Front 70

homology

Back 70

similarities inherited from a common ancestor >> sequences in DNA

Front 71

homoplasy

Back 71

traits similar in two species not because those traits were present in a common ancestor but because similar traits evolved independently in two distantly related groups

evolve similar features independently due to similar environments
causes of homoplasy: convergent evolution and reversal

Front 72

what does homoplasy predict about genetic and developmental homologies?

Back 72

they should be nonexistent similarities are due to convergent evolution so we should see different genes and developmental pathways involved

Front 73

convergent evolution

Back 73

occurs when natural selection favors similar solution the problems posed by a similar way of making a living >>

doesn't occur in common ancestor of similar species
genes organized in similar way
similar function
similar patterns in time and space

Front 74

reversal

Back 74

trait that reverts to previous state >> common in DNA sequence data

Front 75

homology/homoplasy

Back 75

homology is more common than homoplasy because the least change is the most homology and least homoplasy

Front 76

SINEs

Back 76

short interspersed nuclear elements
genes that jump from place to place on chromosomes (parasitic sequences similar to viruses)

insert randomly in organisms find 2 species that share because sines its because of common ancestor because its an unlikely for that to reappear again in the same place in a chromosome

Front 77

Species

Back 77

population or group of populations in which evolutionary forces are acting independently

sexual reproduction only
genetically isolated from each other

Front 78

speciation

Back 78

evolution for 2 or more distinct species from a single ancestral species >> on phylogeny its a splitting event

occurs by reproductive isolation which breaks down into allopatric speciation and sympatric speciation

Front 79

species theory

Back 79

new species are created by

-genetic isolation: lack of gene flow

-genetic divergence: mutation, selection and drift proceeding independently in isolated populations

Front 80

hox genes

Back 80

similar genes found adjacent to one another on the chromosome, sequence of base pairs and products of hox genes have similar functions

Front 81

genetic distinctions

Back 81

occur because mutation, selection, and drift act on each species independently of what is happening in other populations

Front 82

bio species concept

Back 82

criteria for identifying a species is reproductive isolation
adv: no gene flow occurs between pops that are repro. iso. from each other
dis: can't resolve for geographically isolated asexual species

Front 83

morphospecies concept

Back 83

distinct morphology and distinct types
adv: widely applicable to sexual and asexual fossil species
dis: can be idiosyncratic experts disagree features to distinguish are subjective

Front 84

phylogenetic species

Back 84

smallest monophyletic groups on a tree of populations
adv: widely applicable and testable
dis: often reliable trees aren't available

Front 85

subspecies

Back 85

populatiosn that live in discrete geographic areas and have distinguishing features such as coloration or calls but aren't considered distinct enough to be their own species

Front 86

Barriers to reproductive isolation

Back 86

premating barriers to gene flow :: habitat >> split in 2 locations
phenological >> caterpillars summer and spring
behavioral
-gametic
-mechanical
postmating barriers to gene flow ::
-hybrid inviability
-hybrid sterility

Front 87

what isolating mechanism is most important for speciation?

Back 87

ecogeography >> population divided into different locations not interbreeding because different places

Front 88

Mechanisms of Genetic Isolation

Back 88

allopatric speciation (different land)

sympatric speciation (same land)

Front 89

Allopatric Speciation

Back 89

populations separate geographically then evolutionary forces act on them independently

via
dispersal and vicariance

Front 90

Dispersal

Back 90

founder event where drift causes changes in allele frequencies in newly founded populations
drift will cause old and new pops to diverge and physical separation btwn pops will reduce/eliminate gene flow
GENE FLOW prevents speciation
the number of individuals stay small for many generations and drift cont' to alter the allele frequency

Front 91

Vicariance

Back 91

splitting of exiting range into fragments >> external factor splits species

Front 92

Sympatric Speciation

Back 92

(same land) gene flow can stop or be reduced enough to produce speciation even while populations are in the same geographic area
>> different pollinators reduce or cut off gene flow and then divergence is selection for traits that attract different pollinators

Front 93

polyploidy

Back 93

certain type of mutation especially in plants

mutation reduces gene flow between mutant and normal or wild type individuals because mutant individuals have more than two sets of chromosomes

Front 94

Autopolyploid

Back 94

individuals are produced when a mutation results in a doubling of chromosomes all come from the same species
>> can lead to reproductive isolation and speciatino

Front 95

allopolyploid

Back 95

individuals created when parents that belong to different species mate and produce an offspring where chromosome number doubles

Front 96

microevolution

Back 96

allele frequency changes within a species due to selection mutation migration and drift

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macroevolution

Back 97

speciation and the origin of higher taxa (orders classes phyla kingdom) --

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micro and macro

Back 98

micro to macro evolution its a continuous process the difference is in scale

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fossils

Back 99

piece of physical evidence from an organism that lived in the past >> only way to compare phenotypes of earlier organisms

Front 100

how do we get fossils ?

Back 100

rapid burial and removing organisms from O2 rich environments

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fossilization

Back 101

is a rare event its not random and is where oxygen is not abundant so decomposition doe not happen

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types of fossils intact

Back 102

intact :: preferred frozen whole organism

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types of fossils compression

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compression:: sediment accumulated on top of leaft and compressed into thin carbon rich film

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types of fossils cast fossil

Back 104

branch decomposed after it was buried left a hole filled with concrete or dissolved minerals faithfully creating a cast of the original

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types of fossils permineralized

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gradual replacement of organic content in the cell >> form into sstone and decays slowly and allows dissolved minerals to infiltrate cells gradually and harden into stone>>trace fossils footsteps

Front 106

the fossil record is biased how?

Back 106

record is nonrandom sample of the past
contains bias'
habitat bias: organisms that live near sediment are more likely to fossilize
temporal bias: common species are represented more
taxonomic bias: hard bodied animals are much more likely to fossilize than soft bodied animals
abundance bias: species that are abundant widespread and present for long periods of time leave evidence more often

Front 107

case study: tetrapod limbs

Back 107

HYP: evolved from fins of lobe finned fish
phylogeny is based on skull characteristics

Front 108

what corroborating evidence do we have about the monophyletic group that developed tetrapod limbs?

Back 108

1) geologic record/timescale establishes ages of sediment and other rocks relative to each other >> support
2) radiometric dating establishes the absolute ages of fossil bearing rocks >> s.
3)associated fossils and nature of host rock support hyp of aquatic to semiaquatic terrestrial transition >> s.
4) comparative morphology supports hyp of homology in limb
5) evo-devo research supports the hyp of homology in limb events
6) phylogeny of early lobe finned fish and tetrapods
7) comparisons with extant taxa support the fins to limb hyp.

Front 109

adaptive radiation

Back 109

rapid diversification of a single lineage into an array of species that must fill a wide variety of ecological niches >> produce star phylogenies

should include:
-monophyletic group
-rapid speciation
-species diversified ecologically

Front 110

niche

Back 110

range of habitats or resources used by a species (ways of making a living)

Front 111

why do adaptive radiations occur?

Back 111

1) ecological opportunity:
- other competitors/species are wiped out
- colonize new habitat
2) morphological innovation
- new morpho. trait that is an adaptive breaktrhough
- provides new ways of acquiring resources or ability to occupy new habitats
>> opens up the previously unavaliable

Front 112

Genetic Mechanisms of Change

Back 112

diversification can take place through:
-gene duplication (new genes new body hyp)
-change in gene expression
mutation is factor in all change and diversification

Front 113

New genes new body HYP

Back 113

explanation for Cambrian explosion when most body shapes evolved
hox genes : explanation of the hypothesis , tells body when to form an appendage (time/placing of limbs)

Front 114

gene duplication

Back 114

would have occurred before or after the explosion and provide new copies of exiting homeotic genes

Front 115

new genes make what possible?

Back 115

make new body plans and appendages recorded in the cambrian explosion possible

Front 116

gene expression

Back 116

changes in expression and function of exiting genes have been equally or even more important

Front 117

background extinction

Back 117

normal extinction rates due to normal rates of environmental change (natural selection)

Front 118

mass extinction

Back 118

at least 60% of species present go extinct in less than 1 million years due to extreme rates of environmental change (like species level bottleneck or drift at a species level)

Front 119

causes of mass extinctions

Back 119

impact hypothesis: asteroid hit the earth and initiated wild fires cooling effect etc.

world went to hell hyp: global warming anoxic gases etc.

Front 120

Permian Triassic Mass Extinction

Back 120

most cataclysmic mass extinction of animals in the fossil record>>
due to global climate change

Front 121

Cretaceous Tertiary (KT) Mass Extinction

Back 121

most famous mass extinction of animals in the fossil record >>
due to impact of a meteorite/asteroid

Front 122

Microbes

Back 122

any microscopic organism including bacteria archaea fungi protists microscopic plants and animals

Front 123

Tree of life for Bacteria and Archaea

Back 123

bacteria is outgroup 2nd is and 2rd are even Archaea and Eukarya >> common origin all types of organisms share genetic code

Front 124

morphology of bacteria and archaea

Back 124

bacteria and archaea are prokaryotes (paraphyletic group not including all descendants) their chromosomes are NOT surrounded by nuclear envelope - few membrane bound structures inside cell and relatively simple cytoskeleton
>> almost all unicellular most species cell is smaller than most eukaryotic cells
>> vary in shape from spirals to pills
>> * all but few have cell walss
>> within bacteria 2 types of cells according to dyeing system (Gram-stain)

Front 125

Reproduction of bacteria and archaea

Back 125

B and A are haploid and reproduce asexually by fisison

Bacteria cells can exchange DNA through conjugation

sounds like mitosis but it's NOT

Front 126

conjugation

Back 126

process by which bacteria can exchange DNA >> touch walls and transfer or tube for DNA to travel through

Front 127

Characteristics of Bacteria Archaea and Eukarya

Back 127

Archaea doesn't have peptidoglycan in their walsl

Front 128

Habitats that bacteria and Archaea use

Back 128

use all habitats
some bacteria are extremophiles (extreme environments)

Front 129

Bacteria's 2 fundamental requirements for life

Back 129

1) molecule with carbon carbon bonds to serve as building blocks fo larger molecules
2) chemical energy in the form of ATP

Front 130

Two ways to obtain carbon building blocks

Back 130

1) heterotrophs: from other organisms (sugars) through absorption or predation
2) autotrophs: synthesize molecules from simple carbon containing molecules CO2 and CH4
-- different sources of carbon

Front 131

Methods of obtaining ATP

Back 131

1) phototrophs: convert light energy to ATP through absorption or predation
2) organotrophs: oxidize sugars or other reduces carbon containing molecutles to produce ATP
3) lithotrophs: oxidized reduction in organic molecules to produce ATP

Front 132

is fungal or bacterial infection harder to treat in humans?

Back 132

fungal is harder because bacteria is closer to us

Front 133

making atp in organotrophs and lithotrophs

Back 133

reduction oxidation reactions involve transfer of electron from one molecule to another
-- in cells molecules or ions used as electron donors have more potential energy than electron acceptors
--- in plants and animals glucose (sugar) is electron donor and oxygen is the electron acceptor

Front 134

photosynthesis

Back 134

glucose + O2 = CO2 +H2O+ATP + heat

Front 135

what can bacteria and archaea use as a source of high energy electrons for producing ATP?

Back 135

can use virtually any molecule with relative high potential energy

Front 136

why is bacteria important?

Back 136

Bioremediation
1) Nitrogen
2)oxygen revolution

Front 137

Nitrogen under Bioremediation for bacteria

Back 137

if no nitriogen fixing bacteria had existed then too little fixed N would have been produced to make large quantities of protein needed to build a large body
-- multicell organisms would be rare to non existent

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Oxygen Revolution under Bioremediation for bacteria

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cyanobacteria were responsible for fundamental change in Earth's atmosphere from one dominated by N gas and CO2 to one dominated by N gas and O

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bacteria and disease

Back 139

exposed to bacteria then get disease like ZOMBIES`

Front 140

chemosythesis was found to be significant after what?

Back 140

after the discovery of hydrothermal vents it was found that chemosynth. plays significant role although there is photosynth.

Front 141

land plants

Back 141

evolved from green algae, other types of algae have different chlorophyl

Front 142

What are challenges and advantages to life on land?

Back 142

1) sunlight and CO2 are more available
2) threat of desiccation (dehydration)
3) transport water through plant body
4) establish an upright body to compete for sunlight
5) transport gametes without water

Front 143

how did plants resist drying?

Back 143

1) cuticle
2) pores and stomata

Front 144

Cuticle

Back 144

waxy water tight sealant
adaptive significance was that plants able to survive in dry environments

Front 145

Pores and stomata

Back 145

though cuticles are useful plants need to perform photosynthesis sooo >>

adaptive significance is pores allow gas exchange and stomata regulate gas exchange and control water loss from the plant

liverworts DON'T have stomata

Front 146

how do plants transport water and nutrients?

Back 146

vascular tissue ; highly organized interacting groups of cells that are specialized for transporting H2O and nutrients

Front 147

types of water conducting cells

Back 147

1) tracheids; first water conducting cells, pores die at maturity "pipes" pits are places with out secondary cell walls where liquid can pass
2) vessels, open tubes with reinforced sides >>
holes with no primary or secondary walls (perforations)

Front 148

significance of vascular tissue

Back 148

replace water lost when stomata open and structural support of secondary cell walls often lignified

Front 149

how did plants counteract reproduction on land?

Back 149

gametangia and embryophytes

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Gametangia

Back 150

specialized reproductive cells >> multicellular structures that protect developing gametes from drying and mechanical damage
--> all land plants have except angiosperms (structures inside the flower perform same function)
--> male antheridium and female gametangia (archegonium)

Front 151

Embryophytes

Back 151

eggs retained and embryo develops inside the archegonium (=land plants are embryophytes)
--embryo develops inside parent and can be nourished by it >> nutrients from gametophyte tosporophyte >> protection for egg and embryo from dying redator

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adaptive significance of embryophyte condition

Back 152

nutrients from mom via transfer cells and protection

Front 153

adaptive significance of pollen

Back 153

sperm are naked and have to swim to the egg
dependence on water/rain
in transit sperm are exposed to drying

Front 154

pollen

Back 154

male gametophyte which gives rise to sperm cells via mitosis >> encased in tough coat (sporopollenin = resistant to dying)
>> transported by wind insects birds bats

Front 155

seed

Back 155

embryo and food supply surrounded by tough case
>> advangtages = food supply
>> disadvantage = offspring can end up in bad places

Front 156

adaptive significance of seeds

Back 156

nutrients from mom via storage in seed protection and dispersal

Front 157

the evolution of the flower

Back 157

elaboration of heterospory >> key innovation is the evolution of the ovary (protect female gametophytes from insects and other predators)

evolution of flowers made efficient pollination possible

Front 158

pollination

Back 158

correlations between flower structure and pollinator (coevolution; pattern of evolution in which two interacting species reciprocally influence each others adaptations over time)

Front 159

what hypothesis are we invoking in making these correlations about pollination?

Back 159

1) natural selection has favored the evolution of flowers that are efficient in attracting pollinators (heritable variation, differential reproductive success)
2) routinely observe that hand pollination results in higher seed production than natural pollination

Front 160

what does the observation of hand pollination resulting in higher seed production mean?

Back 160

it means that reproductive success is limited by access to pollen = mates

Front 161

why is selection on flower traits strong?

Back 161

this si because attracting pollinators is critical for achieving reproductive success

Front 162

Fruits

Back 162

structure dervied from ovary that contains seeds, nutritious and colored found in angiosperms

Front 163

what did the evolution of fruits do? why was it significant?

Back 163

made efficient seed dispersal possible and plant disperser coevoultion

Front 164

key innovation

Back 164

organismal trait >> new tool that allowed the descendants to live in new areas exploit new sources of food and move in new ways

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ecological opportunity

Back 165

availability of new or novel types of resources that are characteristic of the environment

Front 166

animals

Back 166

monopyhletic group distinguished by
-multicellularity
-directed movement
- ingestive feeding

Front 167

multicellularity

Back 167

many cells, some have
specialized functions; may or may not be organized into tissues.

cells bind to each other, communicate, division of labor (some function in feeding, structure reproduction)

Front 168

directed movement

Back 168

most move
at some stage in the life cycle

Front 169

ingestive feeding

Back 169

a few are
parasitic (absorptive feeding)
but most take in prey.

Front 170

body plan

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animal's architecture major features of its structural and functional design

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tissues

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groups of cells taht are specializeed for a particular function (all animals beside/ including some sponges have tissues)

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origin of tissues

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epithelium (only sponges have)
other animals are diploblasts and triploblasts
germ layers: tissues in embryos
a) ectoderm
b) mesoderm
c) endoderm

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what are the germ layers?

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ectoderm >> skin and nerves
mesoderm >> muscles and connective tissue
endoderm >> gut lining

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diploblasts

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two buds .. embryos that have two types of tissue layer
>> ectoderm and endoderm

muscle is simpler and derived from ectoderm

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triploblasts

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three buds .. embryos have three tissue layers
>> ectoderm mesoderm and endoderm

the mesoderm is between the ectoderm and endoderm

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body symmetry

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animal is symmetrical if i t can be divided by a plane such that resulting pieces are nearly identical

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radial symmetry

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have at least two planes of symmetry

>> diploblasts

echinoderms reverted to radial symmetry

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bilateral symmetry

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one plane of symmetry

>> triploblasts

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cephalization

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evolution of a head or anterior region where structures for feeding sensing the environment and processing information are concentrated

ganglia/brain + sensory organs + mouth in head region

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asymmetry

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no planes of symmetry (sponges)

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posterior region

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designed for reproduction digesting and locomotion

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coelom

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fluid filled cavity lined with mesoderm
1) created a container for the circulation of oxygen and nutrients along with space where internal organs can move independently
2) main importance: functions as hydrostatic skeletons (soft bodied animals can move even without fins and limbs)

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acoelomates

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no enclosed body cavity

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pseudocoelomates

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have enclosed body cavity partially lined with mesoderm

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coelomates

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enclosed body cavity completely lined with mesoderm

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cleavage

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series of mitotic divisions without cell growth
>> divides egg cytoplasm and results in a ball of cells

protostome ends in spiral cleavage
deuterostome ends in right angles or radial cleavage

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protostome development

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spiral cleavage
>> mouth first gastrulaltion
>> coelom from mesoderm blocks

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deuterostome development

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radial cleavage
>> mouth second gastrulation
>> coelom from pinched off mesoderm

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tube within a tube design

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basic animal body is a tube within a tube >> inner tube is individuals gut and outer tube forms body wall mesoderm in between forms muscles and organs

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Segmentation

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repeated structural units in a body >> annelids (segmented worms) arthropods and vertebrates

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Growth Patterns

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molting vs. continuous growth

metamorphosis

ecdysozoans grow by molting (shed old external covering expand and grow new one)

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metamorphosis

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advantage >> reduce competition for food between juveniles and adults

adv. in the ocean >> dispersion

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adaptations to live on land

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1) gas exchange (respiratory system)
2) avoid drying out (cuticle, shells)
3) move in high gravity environment (hydrostatic skeleton or exoskeleton)
4) reproduction in land (internal fertilization, vivparity, ovoviparity, an egg that would not dry in land)

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deuterostomes

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largest bodied and some most morphologically complex animals

4 phyla
chordates echinodermata subphyla vertebrata and phylum chordata

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water to land transitions in protostomes

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1) arthropods (insects, crustaceans)
2) mollusks (snails, slugs)
3) roundworms (C. elegans)
4) annelids (e.g. earthworms)

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phylum chordata

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a phyla of deuterostomes

all chordates have
1) notochord
2) pharyngeal gill slits
3) CNS with dorsal nerve cord
4) a tail that extends past the anus

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deuterostomes

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largest bodied and some most morphologically complex animals

4 phyla
chordates echinodermata subphyla vertebrata and phylum chordata

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notochord

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present at least in embryo
stiff rod under dorsal surface

adaptive significance: endoskeleton in vertebrates and organizes dorsal structures in embryos

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water to land transitions in protostomes

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1) arthropods (insects, crustaceans)
2) mollusks (snails, slugs)
3) roundworms (C. elegans)
4) annelids (e.g. earthworms)

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pharyngeal gill slits

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openings in the throat

adaptive significance:
filter feeding
>> in fish, form gills

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phylum chordata

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a phyla of deuterostomes

all chordates have
1) notochord
2) pharyngeal gill slits
3) CNS with dorsal nerve cord
4) a tail that extends past the anus

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notochord

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present at least in embryo
stiff rod under dorsal surface

adaptive significance: endoskeleton in vertebrates and organizes dorsal structures in embryos

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pharyngeal gill slits

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openings in the throat

adaptive significance:
filter feeding
>> in fish, form gills

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Central nervous system in phyulum chordata

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with dorsal nerve cord

adaptive significance:
coordinate movement

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tail in phylum chordata

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extends past the anus

adaptive significance:
movement

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subphylum vertebrata

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monophyletic group distiguished by
1) vertebrae
2) cranium

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vertebrae

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a column of cartilaginous or bony structure that form along the dorsal side of most species and protects the spinal cord

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cranium

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skull, a bony cartilaginous or fibrous case that enclosed the brain it protects the brain and sensory organs

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key innovation in vertebrate evolution

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bones
jaws

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bones

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tissue consisting of cells and blood vessels encased in a matrix made primarily of calcium and phosphate containing compound called hydroxyapatite along with a small amount of protein fibers

-- at present bones functino to move support give shape protect the body of an individual they produce red and white blood cells store minerals and fat participate in detoxification and participate in sound transduction

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jaw

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vertebrates are able to harvest new foods that they couldn't before without jaws

leading hyp: mutation and natural selection increased the size and modified the orientation of the gill arches

insects even developed jaws that work in different ways from ours

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3 hypotheses to support the gill arch hyp:

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1) both gill arches and jaws have flattened bars of bony/cartilaginous tissue that hinges and bends forward
2) during development the same population of cells gives rise to the muscles that move jaws and the muscles that move gill arches
3) unlike most other parts of the vertebrate skeleton both jaws and gill arches are derived from specialized cells in the embryo called neural crest cells

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tetrapods key innovations in transitioning to land

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limbs
reproduction on land :
amniotic egg, placenta and the elaboration of parental care

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reproduction on land for tetrapods

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amniotic egg
placenta
elaboration of parental care

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amniotic egg

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oviparous species
have shells that minimize water loss at the embryo, bathed in liquid
-- have embryo that is enveloped in a protective inner membrane or amnion
-- yolk sac contains nutrients the allantois contains waste and the chorion allows gas exchange

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placenta

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viviparous species
give birth >> have organ called placenta rich in blood vessels and facilitates the allow of oxygen and nutrients from mother to offspring
after development period called gestation >> embryo emerges from mother's body

independent and free process of parental care

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ecology

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study of how organisms interact with their physical and biological environments
--> ecology is concerned with the web network of relations among organisms at different scales of organization

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behavior

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study of what organisms do how they do it in terms of genetic neuronal and hormonal mechanisms and why in terms of fitness

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behavioral ecology

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study of how organisms make decisions when they interact with various aspects of their environment

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Fixed Action Patterns (FAP)

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highly stereotypical behavior patterns that are usually triggered by simple stimuli called signal stimuli or releasers

examples of innate behavior

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innate behavior

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behavior that is inherited and shows little variation based on learning or the individuals condition

once started continue to completion

all animals show some degree

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flexible or condition dependent behavior

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behavioral change in response to learning and to show flexibility in response to changing environmental conditions

>> individuals response to stimulus varies with situation

optimal foraging theory >> animals should maximize their feeding efficiency

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how are costs and benefits measured?

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in terms of their impact on fitness

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learning

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change in behavior based on experience
>> important in species that have large brains and life dominated by complex social interactions

in species that do learning FAPS and other inflexibles with stereotyped behaviors are rare instead these are capable of wider range of behavior

simple types :
1) classical conditioning
2) imprinting

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classical conditioning

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type of simple learning
>> individuals trained by experience to gvie the same response to more than one stimulus >> even a stimulus that has nothing to do with the normal response

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imprinting

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another simple type of learning that takes place in newly hatched ducks and geese

adopt as their mother the first moving thing they see

fast and irreversible and occurs only during a short critical or sensitive period

humans learning language maybe?

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operant conditioning

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animal must do something to gain a reward (positive reinforcement) or avoid punishment

rat and press bar get food

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bird songs

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more complex learning >>

depending on bird species

can be innate and may be highly stereotyped (chickens)

singing can be heavily influenced by learning but learning is constrained to certain periods and occurs only in response to certain stimuli (white crowned sparrows)

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cognition

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recognition and manipulation of facts about the word combined with the ability to form concepts and gain insight

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adaptive significance of learning

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helps organisms cope with challenges from their environment

type of learning is correlated with the type of environmental unpredictability it encounters

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sexual selection

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selection based on success in courtship

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why do males look different than females?

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1) heritable variation in appearance and/or courtship behavior
2) individuals experience differential success in obtaining mates

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fundamental asymmetry of sex

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in most species females invest much more in offspring than males do

>> female fitness limited by an ability to gain resource required to produce eggs and rear young
>> male fitness is limited by ability to attract mates --> sexual selection should be much more intense in males than females

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sexual selection via male male competition

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female makes a large egg cell
fight for female and territory males that win tend to be a lot bigger than females so the advantage for fitness is d\ue to sexual selection

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sexual selection when females choose

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if reproductive success is not limited by access to males and if males compete for females females should be choosy about males

choose
1) good genes (good alleles)
alleles associated with disease resistance
2) resources needed for egg formation to rear young is nutrients parental care

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result of sexual selection males

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males compete for access to females/eggs >>
male combat
sperm competition
display (colors vocalizations ornaments engineered structures)

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result of sexual selection females

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should be choosy
resources
good genes
sexy sons

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kin selection/ altruism

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behavior that is costly to the actor and beneficial to the recipient where costs and benefits are expressed in terms of fitness

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difference between kin selection and natural selection

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natural selection >>
asocial : survive > grow > reproduce = fitness

kin selection >>
social population: survive> grow> repro = direct fitness
help relatives survive > grow > repro = indirect fitness

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inclusive fitness

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direct + indirect fitness combined

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when do alleles that lead to altruism increase in frequency in a population

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alleles for altruistic behavior will increase in frequency if they increase the fitness of individuals (where that allele is likely to be present)

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when will altruism evolve?

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benefit * relatedness > greater than cost

then mutation conferring increased indirect fitness via altruism will be favored by kin selection

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prezygotic isolation

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biological species conept >> reproductive isolation the way to test it is pre/postzygotic isolate

>> separate different species so they can't mate

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postzygotic isolation

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biological species concept >> the offspring's of matings between members of different species don't survive or reproduce = inviable