BIOB51: Final Exam

Asexual species

Organisms where all members are the same sex, reproducing without the need for a mate, leading to rapid population growth.

Sexual species

Organisms requiring a mate to reproduce, resulting in a 50% male and female offspring ratio and a slower reproduction rate compared to asexual species.

Muller’s ratchet

The accumulation of irreversible harmful mutations in asexual populations over generations, leading to decreased fitness.

Genetic load

The burden of accumulated deleterious mutations over time, more prominent in asexual populations compared to sexual populations.

Red Queen effect

The concept that sexual reproduction provides an advantage in the evolutionary arms race, where constant adaptation is necessary to maintain fitness.

Snails

66% of the population of sexual and asexual are asexual females. There is variation with different frequency of parasitism, intensity of infection correlates with frequency of males. Sexual populations have an advantage to fight off parasitism or something.

Differential parental investment

Unequal investment in offspring between males and females due to differences in reproductive biology and behavior. Males deal with uncertain paternity, and their sperm is smaller.

Operational sex ratio (OSR)

The ratio of males to females capable of reproducing at a given time, influencing mating strategies and competition. Slower rate of reproduction by females leads to male-biased OSR (females are limiting with male-biased OSR).

Sexual dimorphisms

Result from sexual selection, situation where male and female look different. Ornaments (attractive traits, intersexual), armaments (weaponry, intrasexual).

Sexual selection

The process where certain traits increase mating success, leading to differential reproductive success between individuals.

Benefits of female choice

• Direct benefits: benefit the female directly. For example, food, nest sites, protection

• Indirect benefits: benefits that affect the genetic quality of the female’s offspring

Darryl (female choice)

2 different species of cricket and grasshopper. Female is holding what the male gave to her, and it stays on females abdomen, pumping sperm into her, or they might give a food gift. Larger egg will give larger offspring typically.

• Female being choosy for best spermatophore in creases size of eggs and amount you can lay.

Female red back spider (Andrade)

her mate is getting eaten. Sperm brought from pretty pale, inserts in female, males can only make it twice, and then becomes the ultimate gift to females. It lays on her fangs.

Trinidadian guppies

males vary in colouration, orange females are most interested in. They painted pennies and females pecked far more orange, coinciding with preference for orange men. The preference of colour came before preference in females.

Mutual courtship behaviour

mutual because input of sexes is the same. No disparity (males and females choose each other).

Monogamy

A mating system where one male pairs with one female exclusively, promoting parental care and shared investment in offspring.

Polygamy

• Polygyny: males mate with multiple female (females only mate with single males)

• Polyandry: females mate with multiple males.

Sperm competition

sperm from multiple males compete to fertilize the egg, internally competitive. Males (or their sperm) utilize several strategies to increase fertilization success.

Penis of male aedeagus

Inserts and scrubs out sperm of previous male, increase chance of paternity. Longer spines means more fertility. Damages female internally and can kill her.

Pre-chicken domestication

females are storing sperm, can somehow tell if it is from something related to them or not related to them

Cryptic female choice

Red Junglefowl. Females store sperm following insemination, more sperm from unrelated mates than related mates. Some feral populations of domesticated fowl - females can forcibly eject ejaculates following insemination. Pick least related male to avoid inbreeding.

Distal-less

important for legs and mouth and antenna. Changes in the expressions can change stuff. Varying degrees of expression have varying effects. Normal, mild reduction and moderate reduction each have a drop in male advantage. (water bugs and grabbing)

RNA interference

Effective way to experimentally decrease gene expression. Dll dsRNA was injected into nymphal male water striders. Selectively binds to correlated RNA, causing RNA to degrade and shut down before protein made. They can stop the development of the antenna.

Male sand gobies

Guard and cover eggs with sand, remove algae, selectively eat some eggs to increase offspring survival. Mostly in a low oxygen position.

Life history

Strategies for reproducing, growing, and surviving that an organism uses during its life.

David Reznick

• Water pools from waterfall, pools differ in amount and type of predators inside of them. Predation pressure and life history traits amongst guppies.

• Killifish - Rivulus Hartii, can only kill the small babies, while spike (large) goes after the young and the adults.

• Guppies at the bottom are from live birth, using more of female’s resources.

Ryan Cowslick and Brian Cough

Is there a tradeoff between growth and reproduction. Opened up female and did a surgery. Ovaries removed or things were moved around. Prevented reproduction, they grow to a heavier mass and survive longer years with the inability to reproduce. Allocating resources comes at a cost of growth and survival.

Pipefish (Adam Jones)

Related to seahorses. Brood pouch, females make the egg and fertilize and transfer to male to carry. Males have fewer mates, males mate much quicker with larger females transfer more eggs and produce more viable offspring. Increase number of offspring

Meiotic drive

Produce more of one than the other. Potentially through miscarriage, cannibalism.

Triver-Willard hypothesis

Mother alters sex ratio based on condition, producing females in poor condition and males in good condition. Males benefit more from being big and able to attract mates.

Seychelles warblers

• High resources: females favoured, up to three helping daughters is beneficial (88% daughter)

• Low resources: males favoured, disperse away from poor habitat. (23% daughter)

Red junglefowl

opportunities to ‘alter’ sex ratio: Can lay an egg once a day. Calcium layer is put on an hour before laying. Selectively reabsorb eggs from one way or another, cryptically choosing. When egg comes down the line, one passes through and one is dumped

Parental conflict

Disagreement between parent and offspring regarding investment, optimal allocation differs. Mother withholding energy so she can allocate them later to other kids. Bird babies have ornamented mouth, parents are attracted to the mouth and the sound.

Eurasian penduline tit

Nest is an extended phenotype, how females choose males (males sing around their nest). Enlarge nest and one will choose to incubate. One third of the nests are abandoned and the eggs are just sitting there - why might you abandon → increased reproductive success. Males and females aren’t sure when to leave cuz whoever stays has to stay. Females hiding eggs.

Sibling rivalry

Fulica americana, babies are brightly coloured. All orange and all black, exactly same amount of feeding. When he had some orange and some all black they much preferred the orange.

Genomic imprinting

Epigenetic effect where parent-of-origin genes are expressed differentially, involving methylation.

In one experiment, silencing maternal growth-inhibit gene makes them grow larger than normal. Father’s growth promoter gene being kicked out made mice born smaller.

Senescence

Deterioration with age. Caloric restriction can slow down the aging process. Genes involved in repair switched on under stress. May involve trade-offs. C. elegans mutants that age more slowly have lower fitness.

Species

Smallest independently evolving unit. Follow independent evolutionary trajectories. Defining species is contentious. 22 different theories about how to define what a species is exists. What is a species is a man made concept, problem with lines being poorly defined. Species is the tips of branches and we’re still sorting them out today.

Extant

More than morphology (behaviour, geography, dispersal tendencies). Luxury and curse. Lines are less distinct, with abundant overlap.

Phylogenetic species concept (PSC)

Smallest possible group descending from a common ancestor; recognizable by unique, derived traits. Useful for systematics. Focuses on phylogenetic history.

Biological species concept (BSC)

Species are groups of potentially interbreeding populations that are reproductively isolated from other such groups. Works well with sexually reproducing animals and is the most common species concept.

General lineage species concept (GLSC)

species are metapopulations of organisms that evolve independently from other metapopulations.

• Metapopulation: group of spatially separated populations of the same species that interact at some level. Significant gene flow between metapopulations = same gene pool.

Geographic barriers

Extrinsic properties of landscape that prevent gene flow → allopatry

Reproductive barriers

Geographic barriers and reproductive barriers prevent gene flow, leading to allopatric speciation.

Boulder star coral species complex

One species that will eventually become two species. They flow to areas and new coral starts to grow. Release of gametes.

Premating barriers

Issues with timing of reproduction (allochronic speciation - reproducing at different times). Issues with pollinator isolation (monkey flowers).

• So few hybrids because of the pollinator issue and where flowers are found. 0.6 elevation issue, 0.4 pollinator issue.

• Mimulus lewisii → bee pollinated, at higher elevations

• Mimulus cardinalis → hummingbird pollinated, lower elevations

Postmating, prezygotic barriers

Physical damage to reproductive tract (beetles), gametic incompatibility (pollen fails to penetrate and fertilize other species).

Postzygotic barriers

Hybrids are produced but have low fitness. Hybrid inviability, hybrid sterility, ecological inviability, behavioural sterility. Ring-necked dove and rock dove cannot create good offspring. B-D-M incompatibility. You have ancestors on two different loci but only one allele, hybrids should be heterozygotes, otherwise they’re unviable.

B-D-M incompatibility in Monkey Flowers

2 loci by QTL analysis (chromosome 6 & 13). Only looking at hybrids, homozygous have much lower compatibility, if your hybrid is homozygous it dies. Invisibility at different loci.

Allopatric speciation

Differences from through space. Vicariance and dispersal. Islands provide this opportunity. Crickets in Hawaii.

Vicariance

the physical splitting of a habitat (like lizard example)

1. chance separation

2. genetic drift and selection

3. two populations are isolated

Dispersal

population moves to new habitat, colonizes and finds new population (darwin’s finches originally dispersed from Ecuador to inhabit Galapagos Islands)

1. Dispersal and colonization

2. Genetic drift and selection

3. Two populations are isolated

Reinforcement

Selection favors prezygotic isolation mechanisms, preventing hybridization, and reinforcing divergence that has already begun. Premating, reproductive character displacement. Field crickets in texas.

Field crickets

Texenis and rubens. Texenis lives closer to texas, while rubens is in Florida. They overlap in an area (return to sympatry), there is a lot of overlap. The male song. Allopatric separation and divergence, when they return the songs overlap considerably with high potential of hybridization. The species song gets a lot different to reinforce difference and females preference follows the switch.

New type of soil

water levels lower and a soil that was full of marine life, and soil is volcanic and has so many nutrients. Area allows a new species to emerge. Despite curly (old) living so close to kentia (new), they are not crossbreeding. This is because they reproduce at different times. Similar to corals. Very little area of overlap. Between 5 and 6 is only reasonable interbreeding time.

Sympatric speciation

Formosa and Pubescens flowers underwent speciation due to pollinator preference, leading to divergence.

Parapatric speciation

Neighbouring populations diverge while still exchanging alleles. Cline (gradient of conditions), hybridization zone until we get speciation. Lizards and sand adaptation Reality showed a lot of gene exchange.

Ecological speciation

Reproductive barriers evolve due to selection for different ecological traits, leading to pre and postzygotic isolation. Grizzly bears isolated.

Allopolyploidy

Formation of a new species through the combination of different species with varying chromosome numbers, leading to rapid speciation. Polyploidy resulting from interspecific hybridization.

Cryptic species

Species that are undergoing speciation but do not show obvious morphological differences, important for measuring biodiversity.

Barcoding: cytochrome C section barcodes a species

Microbial species

Fission recreation is a puzzle. Different microbial species can communicate through projection, which creates convolute for gene transfer, or to ingest.

Horizontal gene transfer

Transfer of genetic material between different species, complicating classification and challenging the traditional species concept.

Macroevolution

Evolution occurring above the species level, involving origination, diversification, and extinction of species over time.

Microevolution

evolution occuring within populations. Adaptive and neutral changes in allele frequencies.

Wallace’s line

not a huge geographic distance, the species North and South of the line do not interact. Deep trench, non-geographic barrier keeping them apart. Between Criental and Australia.

• A northeast kangaroo - population represents descendants of those recently brought by humans

Wallace liked biogeography (study of species distribution across space and time).

Phylogenetic signature

Continent splits in 2, diverging again, 4 new species, a tree would connect by vicariance event 1 showing them collectively diverging

Pattern of geography of marsupials

first pattern based on continental drift, second is based on different characters, there is strong congruence. Original marsupials developed in China, moved across Asia and Europe to N America, and some went back to Asia, or Africa, Antarctica, S America. Species of marsupials in N America, Europe and Asia died off. Only N American marsupials are ones moved up from S America (opossum in Georgia)

Rate of extinction and origination

Scientists use the rates of origination and extinction of species in the fossil record to examine the history of life on Earth. Origination occurs when fossil record indicates a lineage split into distinct clades. An extinction occurs when the last member of a clade dies.

Adaptive radiation

Occurs when new species evolve rapidly to occupy ecological niches in the absence of competition, leading to increased biodiversity. High rates of origination in short period of time.

Coevolution

Reciprocal evolutionary changes between interacting species driven by natural selection, leading to adaptations in performance and fitness.

Mass extinction

A significant increase in extinction rates beyond the background level, often leading to major disruptions in ecosystems and biodiversity.

Permian extinction

60 000 years, in middle of a 500 000 year period of volcanic activity in Siberia. Great lava flows. Lead to anoxic conditions. Continued for so long, why so many organisms went extinct.

K-T extinction (K-Pg)

Thick iridium layer (66 MYA)

First day following the Asteroid, saw tsunamis, forest fires, particles reflected sun out, destroying the base of ecosystems (a lot of plants).

Impact off coast of Yucatan Peninsula. CO₂ and SO₂ in atmosphere (little O₂ for respiration; ocean acidification). Dark dust cloud from explosion blanketed Earth for several years. No matter where, we have never found dinosaur fossils above the line. Dinosaurs are one part, because plants also saw a drastic impact to foundation of ecosystem.

Mutualism

positive/positive relationship between species that raise each other’s fitness

• Pollination, seed dispersal, nutrient exchange between mycorrhizae and plants, farming, animals and microbiota, cleaning

Commensalism

positive/neutral relationship that benefits ones species but has a neutral effect on other species

• Scavengers

Positive/negative relationship

predator and prey, herbivore and plants, virus and host, deceptive pollination (flower tricks insect to coming to it, with no nectar)

Ants and Acacia

ants live on acacia tree and the ants benefit from home inside dried out thorns. Acacia provides specific food as nectarines, with the only biological function being for feeding ants. Fruity nubs for it to eat. Ants provide protection. With vs without ants graph shows the amount of herbivory, amount of foliage. Survival is better with ants.

Geographic mosaic theory

Populations within the same species experience different selection pressures based on their geographic location, leading to varying levels of adaptation.

• Cold-spot: at stasis (no change)

• Hot-spot: intense selection

Coevolutionary alternation

Can occur in interactions involving many species. When one species is in an antagonistic relationship with several species. Optimal species to go after is the smallest population, and then blue gets big, and then go after pink, pink gets big, go after green, green gets big, go after blue again. All populations are just getting bigger and bigger.

Coevolutionary arms race

Evolutionary pattern where species engage in a cycle of adaptation and counter-adaptation in response to each other's strategies, such as predator-prey interactions.

Evolutionary faunas

Animals of a specific region, habitat, or geological period, reflecting the diversity and adaptations of species within a particular context.

Trade-off of life

Geographic ranges show that toxicity levels and resistance levels in species are in tandem, affecting traits like crawling speed in garter snakes.

Attenuated coevolution

Myxoma virus in rabbits showed decreased lethality over time due to a balance between killing and resistance, favoring less lethal strains.

Mullerian mimicry

Non-toxic species mimic toxic ones for protection, leading to warning coloration in various organisms.

Introgression

Movement of genetic material across species boundaries, often through hybridization, influencing genetic diversity.

Diversifying coevolution

Increase in genetic diversity due to varied coevolutionary processes among ecological partners, accelerating population divergence.

Coevolution and extinction

Highly specialized interactions between species can lead to mutual dependence, where the extinction of one species may drive the extinction of the other.

Proximate questions

Address how behaviors are produced and develop

Ultimate questions

Adresses why variations in behaviour influence fitness, and why it evolved

Natural variant approach

studies mutations in natural populations

Jerry Hirsch (1961). Inspired by artificial selection. Mutations occur naturally. More amenables to studies of ecology and evolution.

Flies and geotactic maze experiment, as well as flies and aggression.

Single gene mutant approach

manipulates specific genes to understand behavior.

Seymour Benzer (1967). Inspired by success at dissecting development. Perhaps normal behaviour can be mutated. Caveat: do genes uncovered vary naturally?

ASPS

Advanced sleep phase syndrome. Mutations in copy of period gene. Wake time is advanced.

Conservation of gene function on behaviour (eg. Hox genes)

DNA sequence and gene function conserved across diverse lineages. Broad implications and applications. Genes affect all animals because of whatever.

Foraging gene in honeybees

The for gene regulates the transition from nurse to forager bees, affecting their behavior within the hive.

Vocal learning in songbirds

Genes like egr-1 play a crucial role in song learning and production in birds, influencing their ability to mimic sounds.

Pair bonding in voles

Differences in pair bonding behavior in voles are mediated by neuropeptides like vasopressin and oxytocin, affecting their affiliative behaviors.

Courtship in Drosophila

The FruM gene in male flies is essential for male-female courtship behaviors, and its absence can lead to altered courtship patterns.