Ecology Exam 1

Definition of Science: a system of acquiring knowledge; or, the knowledge itself

The importance of the scientific method

• Media; and conflicting news/bad info
• Need a basic understanding of good science; look for use of good scientific method and proper experimental design

Pseudoscience: False-Science (can not attempted to be refuted or falsified)

What do we mean by the scientific method (steps)? (hypothetico-deductive method)

1. Observation

   1. Be curious; notice small details, be precise

2. Gather information

   1. Synthesize relevant info.; includes peer reviewed articles and know info

3. Hypothesis testing

   1. Hyp Ha: A tentative statement about nature, the purpose of which is to suggest experiments (a ‘best guess’) Null Hyp H0: There is no significant relationship between observation and hyp

4. Prediction

   1. Take the null and put it as a if then statement; but be specific

5. Experiment

   1. A well thought out prediction should suggest the proper experiment with it being replicated with guide lines

6. Conclusion

   1. Descriptive stamtents that best explain the results; compair your studies to other similar studies; if results are inline with previous existing theories in increases our confidence

7. Communication of results

   1. Should report even if you fail to reject the null; you cant get stuck on one hypothesis if its not working

Observational vs. Manipulative Experiments

Obervational (Natural): Take advantage of natural events or natural differences

Manipulative Experiment: higher power to detect differences, more control, more costly; you remove a top predator or mimic a natural occurring event in a lab or field

Publication Process

Maniscrpit order

1. Abstract
2. Intro
3. Methods
4. Results
5. Discussions
6. Conclusions
7. Literature Cited

Submit this work to one journal and one journal only; this helps the publisher save time and not have a double publish and how we can catch bad science with the publisher having this peer reviewed and looked at

Other Scientific methods

• Descriptive Science
  • Observational methods oldest
  • Explanations may come from myth, religion
  • No testable hypothesis
• Induction
  • Similar to descriptive science in that there are no hypotheses
  • Data is subject to analysis but usually no correlation analysis
  • Correlation does NOT equal causation

Once a theory has been tested repeatedly it can be a law or a principle

• Theory of Evolution

Elements of a Good Experimental Design

1. Control

   1. An treatment against which one or more other treatments can be compared.
   2. Identical except does not receive the manipulation under investigation

2. Replication (Sample SIze)

   1. Replication is having more than one experimental unit PER Treatment
   2. Sample size = # of experimental units per treatment (Tanks of fish)
   3. Greater replication: closer to true average, greater power to detect differences

3. Randomization

   1. Process of randomly allocating treatments and controls to experimental units
   2. OR randomly selecting samples from the population of interest

Bias

• Bias is a systematic error
  • A balance of a scale is always 24g heavy
• May involve favoring
  • Sampling streams at road crossings
  • Picking out the easiest to catch mice
  • Can be skewed by personal beliefs, culture, or religious beliefs
• Example of Bias: Craniometry
  • Popular in mid-1800s
  • Ranking people on intelligence by volume of skull
  • Knew which skulls belonged to who did not account for sex and other factors

Quasi-Experiments (one or more key components missing)

1. Money
2. Logistics; rare animals, transportation issues
3. Ethical problems; what is it going to do to humans or animals
4. The independent variable is not manipulated by the researcher
5. Treatment and control groups might not be randomized
6. May lack a true control

Result of a Quasi-Experiment: Researcher is limited in what he/she can say

Types of Variables

Dependent Variable: What is measured. Response variable. End point. Effect

Independent Variable: This is what is manipulated; or the effects of which you wish to determine

Confounding Variable: A variable other than your independent variable, that effects your dependent variable

To see an experiment example look at PowerPoint slides from 2/1

Individuals

Interactions with their environments: temp, water, nutrients, energy

Interaction with each other (social): Mating, protection. etc.

Temperature and what effects it

Microclimates (small-scale weather variation measured in a shorter time period) interact with the local landscape to produce microclimatic variation

• Altitudes can affect micro climates severely
• Aspect (North vs South, valleys, mountains)
• Vegetation (leaf covers in jungles)
• Ground Colors (color of sands or soil)
• Boulders/burrows/caves (create shadows, and cool temperature

MISSED CLASS 02/03/23

Thermal Zones and Ecto/homeo-therms

Ectotherms rely mainly on external factors for body temps

Endotherms heavily relay on internal energy for body temp regulation

A homeotherm has a higher energy output, but can only function over a narrow range of body temperatures

Thermal neutral zone: range of environmental temps. Over which the metabolic rate of a homeothermic animal does not change

Every species has its own thermal neutral zone in which it can function, this is a product of where they reside, arctic species can survive a large range of temperatures for example

Homeostasis requires energy (work)

Homeostasis can be costly if it involves maintaining body temp when the environmental temp outside the thermal neutral zone

• Adaptations by aquatic animals for low tempatures
  • Air breathing
  • Fat or blubber
  • Fur
  • Counter-current heat exchange

Conductive heat loss to water is 20-100x more rapid then air

• This is why otters have fur, it creates little air pockets between the fur and skin and

Counter current heat exchange In aquatic mammals vs fish

• Mammals (dolphins)
  • The stuff furthest away from the heart starts to get colder first
  • Blood moves in opposite directions arteries away from the heart (warm blood) veins move blood to the heart (Cold blood)
  • With the current moving in the opposite directions it creates a heat exchange
• Tuna (cold blooded fish)
  • Oxygen and cold water moves through the gills
  • The viens transport warm blood to the muscles for energy and the artires carry cold blood to the heart creating counter current exchange

Many organisms survive extreme temperatures by entering a resting stage

• Inactivity
  • Seek shelter during extreme temperatures, or just stop moving
• Reducing metabolic rate
  • Torpor: Lower metabolic rate and body temp for a short period of time (Can reduce metabolic rate sigficatly usually just over night tho)
• Hibernation: reduced metabolic rate for months in the winter (cold temps)
• Estivation: Reduced metabolic rate for months in the summer (warm temps)

UNIT Individual-Level Ecology

• Behavioral Ecology
  • Study of social relations
  • Interactions between organisms and the enviroment, mediated by behavior
• Asexual Reproduction
  • Only one parent; no meiosis, no fertilization
  • Bacteria, some fungi, some plants, stargish, waterfleas
  • Less energy required compared to reg. Mating
  • Rapid colonization and more offspring
  • One major flaw in asexual reproduction is the lack of genetic diversity
• Sexual Reproduction
  • Fusion of distinct male and females gametes to produce a zygote
  • Mammals, birds, some plants, many inverts
  • Advantages: genetic diversity
  • Disadvantages: Costly (production of flowers, gonads, elaborate displays)
• Female and males are limited by different things sexually. Females would be resources access and males would be mate access, females produce larger more energy-consuming eggs while males produce small gametes and are less energy-consuming
• Some species’ sex is determined in the womb or egg (aligators)
  • Sex is determined by temperatures
  • <86F→ All females
  • \
    > 93F → All males
  • In between → Mix
  • This would be a frequency-dependent selection

Some organisms are hermaphrodites

• Sequential: starts out one sex, then converts
• Mate choice, or competition for mates, can result in selection for particular traits
  • Sexual selection
• Fitness: the number of viable offspring contributed by an individual to future generations
  • Off spring must reproduce to count as viable
• Sexual selection: Differences in reproductive rates among individuals through differences in mating success.
• Intrasexual selection: individuals of the smae sex fighting over a mate (competing)
• Intersexual selection: one sex chooses mates (opposite sex) based on particualar traits
• Evolution of socialaty may be accompanied by cooperative feeding, DEFENSE OF THE GROUP, AND RESTRICTED REPRODUCTIVE OPPEORTUNITES
• Cooperative breeders
  • Members of groups may have reduced mating opportunities
  • Non-breeders cooperate in rearing others others’ offspring
• Not altruistic
  • Helpers benefit still
  • Kin selection: related, so still passing on some alleles
  • Improed chance of own reproduction: inherit territory; recruit helpers themselves; learn parenting skills
• Kin selection appears to play a key role in the evolution of eusociality
• Eusocilaity: more complex, higher level sociality (Colonies of ants, wasps, bees, termites)
• Major characteristics of eusociality
  • More than one generation
  • Cooperative care
  • Non-reproductive and reproductive castes
  • Castes: groups of physically distinct members with different roles

Cates systems and Eusociality

• Caste: groups of physically distinct members with different roles
• Leafcutter ants have to largest caste system with 29 different castes
• Organisms with caste systems: Bees, ants, wasps, termites
• Haplodiploidy in honey bees
  • Males developed from unfertilized eggs and are haploid (only one allel F)
  • Females are developed from fertilized eggs and are diploid (two allele M and F)
  • Queen can choose wether the egg she lays in fertlized or not creating males and females
  • Evolutionary, it is better for a daughter to help rear he sisters because they are 75% related
• Queens are fed royal jelly throught the larval stage (16 days), while normal workers are feed royal jelly for 2 days in the larval stage
  • Different development, although they have the same genetics
  • Thye have different expression of genes, but this is regulated through nutrition in larval stage
• Queen put out pheromones to chemically suppress other females in the colony

Population Genetics

Population genetics: is important in the study of: Evolution, conservation ecology, ecotoxicology

• Evolution was credited to Darwin and Mendel
• Darwin: wrote the Origin of species by means of Natural Selection (1859)
  • Focused other scientists on the diversity of organisms
  • Evolution: Descent with modification
  • Took a 5 year journey on the HMS Beagle collecting 1000’s of specimens aroccs the world
  • Intruged with the organisms on the Galagos islands; species found here were different then others nearby but still simmilar
• Wallace: also had the same ideas as darwin at the same time
  • Colaborated with wallace
  • Wallace wrote papers later defending darwin but continued to work to be a biogeographer

Lecture Online

• Darwins proposed mechanism for adaptation, or evolucion, is natural selection
  • Natural selection: organisms can change over generations if individuals with certain hertiable traits leave more offspring than others
• Two key observations of Natural selection: over production and variance
  • Overproduction makes it hard for offspring to survive creating good offspring to reproduce, individuals with with best suited traits will leave more viable offspring
  • Variation: exists among individuals in a population, much of this variation is heritable
• Mendel worked on peas which showed great inhearidence and were predictable
• Phenotypic variation among indiviuals in a population results from combined effects of genes (specif alles) in the environment
  • An organims genetic makeup (specific alleles). Usually refers to a particular trait (PP, Pp, pp)
• Phenotype: physical expression of the interaction between genotype and environment.
• Isolated populations are more likely to diverge into a sub-species or a totally new species
• Evolution: changes in allele frequencies over time
• The hardy-Weinburg equilibrium model helps identify evolutionary forces over time (changes in alleles)
  • In a pop. mating at random in the abstinence of evolutionary forces alleles will remain constant
• How to be in HWB equilerbruim
  • No mutations
  • Large (n)
  • No migration
  • Random mating
  • No natural selection (no advantages in alleles)
  • Likely one of these conditions will be meet; leading to not be in HWB
• Agents of change
  • Mutation
  • Genetic drift
  • migration/gene flow
  • Natural selection
• Mutation
  • Random changes in DNA molecules; Can be inherited by offspring of occur in gametes
  • Source of all genetic vartion
  • No effect, detrimental, beneficial
  • Benefical → natural selection, adaptation
  • All different kinds of mutations
• Substituation (or replacement) of nucleotide
• Insertion of nucleotide (everything after that insertion is changed)
• Deletion of a nucleotide (Everything after that is changed)
• Genetic Drift
  • Can change gene frequenecies; especially in small populations
  • Changes due to chance alone (random)
  • Bottle neck
  • Drastic reduction in pop. size
  • By chance, certain alleles may be over or under represented among survivors; usually reduces gentetic diverstiy
  • Habitiat fragmentation and overhunting can cause the bottle neck
  • Founders effect
  • Genetic drift in a new colony
  • Founder population has different allele frequenscies than source pop. (by random chance)
• Migration
  • Transfer of alleles into or out of a pop. (Random)
  • Movement of individuals among populations
  • Immigration
  • Emmigration
  • Increase or decrease of genetic diversity
• Natural Selection (Not Random; Adaptive)
  • Of all causes of evolution, only natural selection is adaptive
  • Random generation of genetic variability leads to differential reproductive success (better fit)
  • Development of pesticide resistance
    • Insecticide only kills off the ones who it works on; leaving the bugs left over to breed with those alleles which are suited for it
• Natural selection is the result of differences in survival and reproduction among phenotypes

Discussion of paper

• Advatages of BACI design: Allows you to take into account;
  • Differences among sites at the start.
  • Environmental changes over time

\