Bio Exam 2 - Chapters 8, 5, 9, 10, and 11. GVSU BIO 215 Dreyer

The principle of allocation

• organisms have limited energy. the amount used for one function reduces the amount available for other functions.

• trade-offs vary with environments

• As the population adapts to the environment, fitness in other environments is reduced

Phenotypic trade-off

A situation in which a given phenotype experiences higher fitness in one environment, whereas other phenotypes experience higher fitness in other environments.

Phenotypic plasticity

the ability of a single genotype to produce multiple phenotypes

Acclimation

an environmentally induced change in an individuals physiology

Biotic variation

adaptations to variation in enemies, competitors, and mates

• like camouflage, and self fertilization in times of low mates

Inbreeding depression

the decrease in fitness caused by mating between close relatives due to offspring inheriting deleterious alleles from both the egg and sperm.

Habitat

a place or physical setting in which an organism lives

Microhabitat

a specific location within a habitat that typically differs from other parts of the habitat

Isozymes

different forms of an enzyme that catalyze the exact same chemical reaction

Migration

seasonal movement of animals from one region to another. Some causes include temperature changes, photoperiod lengths, and food availability.

Dormancy

organisms dramatically reduce their metabolic processes

Diapause

Dormancy in insects associated with a period of unfavorable environmental conditions

Hibernation

a type of dormancy that occurs in mammals in which individuals reduce the energetic costs of being active by lowering their heart rate and decreasing their body temperature

Torpor

brief period of dormancy that occurs in birds and mammals in which individuals reduce their activity and their body temperature to cope with cold temperatures

Aestivation

shutting down the metabolic processes during the summer in response to hot and dry temperatures

Evolution

living things change over generations. Organisms must survive, reproduce, and change

Surviving

Considered successful if the individual survives to reproduce

Reproduction

successful reproduction occurs if their offspring lives

Successful generations

high survival and reproduction

Evolutionary fitness

individuals, populations, species

Relative fitness

More fit than other members of its species

Sufficient fitness

fit enough to continue

Fitness

context dependent. What is fit in one environment may not be fit in another

Life history that achieves maximal fitness

Life forever, reproduce immediately, reproduce continually.

Life history influences

• body plan and lifestyle: small animals tend to reproduce sooner and die earlier

• evolutionary responses to physical conditions, food supply, predators, and other biotic factors

Life history associations

• Long life: delayed reproduction, few offspring per reproductive bout, slow development

• Short life: early reproduction, many offspring per reproductive bout, rapid development

Evolutionary fitness

• We define the fitness of PHENOTYPE.

  • Individuals are fit when the genes they carry get to the next generation

  • because individuals have different alleles, we can have different fitness in the same population of gene pool

Survival and Reproductive fitness

• the genes survive, not the individual, population, or species.

• reproduction means the genes can continue to the next generation

• single genes can have expressions that help or hurt the fitness of the individuals that have them

• a gene can yield a trait to increase its survival

Genes and Reproduction

• genes can continue to the next generation via sexual or asexual reproduction.

  • Asexual: clonal reproduction. cells divide faster

  • Sexual: recombination, produces more gametes

Mutations

the ultimate source of genetic variation.

• only random DNA changes occur.

• some are good, bad, or neutral

Independent assortment and recombination

• only occurs in sexual reproduction

• results in offspring being genetically nonidentical

Genetic drift

• the assumption of neutral change in fitness.

  • variation from generation to generation, resulting from random sampling.

  • some variants get to reproduce, but which ones do vs. don’t aren’t determined by their genes.

  • change by chance

  • more impactful in small populations

Bottleneck effect

population size is reduced for at least one generation, causing reduced genetic variation

Founder effect

reduced genetic variation from the original population. A non-representative sample of genes in the original population

Natural selection

• happens only under constraint

• acts on phenotype, even though the traits under selection are governed by genotype

• characteristics that give a fitness advantage will increase in frequency over the following generations

• results in adaptations that tailor organisms to survive within their environment

Directional selection

Favoring one end of variation

Diversifying selection

favors individuals at both extreme ranges

Stability selection

favors the middle ground between two variations

Sexual selection

Constraint from mate preferences.

• acts on reproductive component of fitness, so the survival component can be compromised

• can agree or disagree with natural selectin pressures acting on the same traits

• A subtype of natural selection. Traits can be the combination of both natural and sexual.

Cooperation/Mutualism

• reciprocity

• benefit to actor, but multiple costs and benefits involved

Altruism

• kin selection, indirect fitness, inclusive fitness

• selection for others that benefit offspring or other relatives

Inclusive fitness

benefit to your genes for performing an act

Hamilton’s Rule

An act is beneficial if the cost to you is less than the benefit discounted by the relatedness.

Inclusive fitness trade-offs

• alarm calls when predators are sighted: decrease personal safety, but increases colony safety

  • alarm calls more often when offspring are around

• division of labor so some individuals are non-reproductive ex. honey bees having the sisters of the queen care for her, but only the queen reproduces.

Kin selection with haplodiploidy

• females develop from fertilized eggs: diploid

• Males develop from unfertilized eggs: haploid

• Sisters share half of genetic material from mother and all from father.

  • increased benefit to helping sisters because their genetic relatedness is 75%

Reciprocity

the evolution of cooperative or altruistic behavior may be favored by the probability of future mutualism

Summary of evolution

• populations change over time in response to constraints.

  • evolve due to biotic or abiotic selective pressures

• expect potential change in:

  • allele frequency, adaptations, co-evolution, and speciation

Aposematic signaling

colorful traits advertise poisonous nature

• creature evolved toxin to ward off or kill predators

Co-evolution

• Some predators evolved a resistance to the toxin

• when two or more species reciprocally affect each others evolution through natural selection

Macroevolution

grandest trends and transformations in evolution, like lungs, legs, amniotic egg, etc

Allopatric speciation

the evolution of new species through the process of geographic isolation

Sympatric speciation

• the evolution of new species without geographic isolation

• splitting an ancestral group into two or more reproductively isolated groups

Life history

• the significant features of the life cycle through which an organism passes

• the full range of changes, habits, and behaviors of a living thing over the course of its life

• details of a species’ life history, how it has evolved, and how we affect it are critical to management.

  • indicators of environmental stress

  • identification of current or future perturbations (harvest, climate change) can influence sustainability

Competitive plants

• low stress, low disturbance environment

• fast growth + nutrient intake

• goal is to dominate productive environments by reducing the growth of other plants

Stress-tolerant plants

• high stress, low disturbance

• slow growth, conserved metabolism

Ruderal (disturbance)

• low stress, high disturbance

• high seed production

• fast life cycle

Fast life history

• greater number of offspring

• shorter life span

• faster growth

• earlier reproduction

• earlier sexual maturation

• smaller parental investment

Slow life history

• fewer offspring

• longer lifespan

• slower growth

• delayed reproduction

• later sexual maturation

• greater parental investment

Fish Life history

• fish fecundity (# of eggs) increases with body size, and body size increases until maturation.

• maximize growth early and then mature at a large size

Carrying capacity

• r: fast life histories, associated with unpredictable habitats or disturbance

• K: slow life histories, associated with stable, predictable habitats

Intermediate life history

Bats have a small body size, long life span, but have early reproduction with only one pup per year

Semelparous

Animals that reproduce once, then die

Monocarpic

plants that reproduce once, then die.

Iteroparous

Animals that reproduce multiple times over their lifespan

Polycarpic

Plants that reproduce multiple times over their lifespan

What affects life histories?

• temperature

• photoperiod

• predator availability

• levels of precipitation

Asexual Reproduction

organisms can produce clones OR genetically variable offspring (parthenogenesis)

Sexual Reproduction

organisms can evolve as separate sexes or as hermaphrodites

Female (Biological Sex)

• Fewer, larger, and more costly gametes

• reproduction limited by access to resources

Male (Biological sex)

• More, smaller, and less costly gametes

• Reproduction limited by available mates

Hermaphrodites

• Simultaneous hermaphrodites: both male and female reproductive functions at the same time

• Sequential hermaphrodites: can switch between male and female reproductive functions. One at a time.

Monoecious

Plants that have separate male and female flowers on the same individual

Dioecious

Plants that contain either only male or female flowers on a single individual

Promiscuity

Males mate with multiple females, and females mate with multiple males. No lasting social bond.

Polygyny

A mate males with more than one female

Polyandry

A female mates with more than one male

Monogamy

One female mates with only one male and vice versa

Dilution effect

The lowered probability of predation to a single animal when it is in a group

Other benefits of living in groups

• high group defense - increased vigilance

• group demonstrations to attract mates of the opposite sex

Costs of group living

Increased spread of illness, parasites, etc. Increased competition in large groups

Eusocial Species

• multiple adults living in one group

• overlapping generations within the group

• cooperation (particularly in offspring care)

• one or a few individuals dominate reproduction

• presence of sterile individuals

• Isoptera and Hymenoptera insect orders

• In mammals, naked mole rats are eusocial

4 Types of Social Interactions

1. Cooperation: Benefits both parties

2. Selfishness: Benefits only the donor

3. Altruism: Benefits only the recipient

4. Spitefulness: Benefits neither