NOT EXAM labs 1-3 + appendix A

Question 1

Adaptation

Answer 1

traits that contribute to an organism’s fitness by increasing its chance of surviving and reproducing

Can be physical feature of body (colour of wings) or behaviour (attraction to certain smells)

Not all traits are adaptations

E.g. reduviid bugs (nymphs) have an adaptation that covers their thorax with a layer of dust or sand which allows dead insects to stick to them and camouflages them from predators → increases their chance of survival

Question 2

New traits and new combinations of traits are created in the population by ________(genetic errors) as well as ______________(mixing of genes through sex)

Answer 2

mutations ; recombination

Question 3

fitness

Answer 3

Fitness can be measured as the number of offspring an individual produces relative to other individuals in the population

Question 4

In order for a trait to evolve by natural selection, the following three criteria must be met:

Answer 4

The trait is heritable

There is variation between individuals within a population for the trait

Variation in the trait leads to some individuals leaving more offspring in the next gen than others (i.e. some individuals have higher fitness than others)

Question 5

Population can also change genetically by random processes (_________) or by the influx of migrants from other populations (________)

Answer 5

genetic drift; gene flow

Question 6

Adaptations for competition for mates

Answer 6

An individual’s fitness depends not only on how long it survives and how well it locates food, but also on how successful it is in competing for mates

An individual that fails to mate will produce no offspring and have a fitness of zero

Question 7

sexual selection

Answer 7

Natural selection arising from variable mating success is called sexual selection

Sexual selection often results in the evolution of differences between males and females in secondary sexual characteristics (characteristics other than ovaries and testes)

Question 8

sexual dimorphism

Answer 8

Differences in the shape or size of body called sexual dimorphism

Question 9

Two principal mechanisms of sexual selection are

Answer 9

intrasexual competition and mate choice

Question 10

Intrasexual competition

Answer 10

Males fight with other males for access to females

Males that defeat their rivals will sire more offspring (so they possess more adaptations for fighting - horns, tusks)

Question 11

mate choice

Answer 11

In many species, females/males are choosy about their mates

Thought to increase the fitness of the “chooser” by enabling it to mate only with healthy individuals (which are thus more “attractive” as mates)

Attractive individuals attract more mates → produce more offspring

Adaptations include elaborate structures, colour patterns and courtship displays that might reveal their health and vigour

Question 12

Phenotype plasticity →

Answer 12

a single genotype can produce different phenotypes in response to its environment

Question 13

phenotype

Answer 13

The phenotype is the “outward appearance” or observable manifestation of a specific genotype

Question 14

overall organism’s phenotype composed of its …

Answer 14

morphological, behaviour and physiology

When variation in the phenotype is observed within a population, the observed variation may result from variation among genotypes (i.e. genetic variation), the environment, or the interactions of both components

Question 15

Evolution depends on ________ traits being passed down from gen to gen

Answer 15

phenotypic

-It’s an organism’s alleles and not its phenotype that are transmitted directly from parents to offspring

Question 16

Continuous phenotypic traits are the result of…

Answer 16

interactions between multiple genes and the environment

Continuous phenotypic traits–>height/skin colour)

Question 17

continuous phenotypic traits

Answer 17

Each of these genes can have a large or small effect on phenotypic expression

These traits referred to as quantitative or polygenic traits

(height, skin colour)

Question 18

Because both gene expression and fitness are dependent on __________, an individual’s ability to respond to environmental conditions in a way that will increase its ________is an important factor in evolution

Answer 18

the environment; fitness

Question 19

Individuals that can exploit the appropriate combination of phenotype and environment will gain the ________
Can be achieved by altering the environment (move to suitable habitat) or altering the _______–

Answer 19

highest fitness; phenotype

Question 20

acclimation

Answer 20

Alteration of the phenotype, called acclimation, occurs in individuals that are able to modify their phenotype in response to environmental variation in a manner that improves fitness

Question 21

Individuals don’t adapt but they ______to their environment
________are capable of adapting to changing environments

Answer 21

acclimate ; Populations

Question 22

phenotype plasticity

Answer 22

When an individual can alter the expression of a phenotypic trait in response to the environment, they are showing phenotypic plasticity for that trait

Ability of one genotype to produce different phenotypes in different environments

Expresses itself as either discrete alternate types or in a continuum

E.g. desert annual plant produces either yellow(dormant) or green(non-dormant) seeds depending upon day length

Question 23

When phenotype plasticity expresses itself in a continuum, the relationship between the environment and the trait in question is known as a …

Answer 23

reaction norm

Question 24

Why aren’t all traits phenotypically plastic?

Answer 24

Possible explanation is that insufficient genetic variation exists(in species or trait) for the evolution of plasticity to occur

-even if sufficient variation exists for the evolution of plasticity, costs and limitations may result in a selective pressure against a trait evolving phenotypic plasticity

-costs associated with producing new phenotypes and maintaining the sensory and regulatory mechanisms required for plasticity may offer a significant selection pressure against the evolution of plasticity for a trait

-at a genetic level, linkage between genes might produce a situation whereby genes promoting plasticity might be linked to genes conferring a low fitness for other traits

Question 25

limitation with producing new phenotypes

Answer 25

A limitation associated with producing new phenotypes is the accuracy with which an organism can correctly process environmental cues in order to appropriately acclimate

Question 26

maladapted phenotype

Answer 26

If an organism incorrectly senses the environment, or the environment changes rapidly, the organism may produce a maladapted phenotype

Question 27

Another limitation is the time difference between …

Answer 27

sensing environmental change and alteration of the phenotype

During this time, the organism will experience reduced fitness as it is not yet acclimated to its new environmental conditions

The greater the change in phenotype, the longer the time lag

Question 28

What could lead to selection for the plasticity of a trait?

Answer 28

One example could be in heterogeneous environments, which change frequently over space/time

An individual that can produce more than one phenotype is more likely to acclimate to the changing conditions than an individual who can express only 1

Question 29

Mechanism behind plastic response

Answer 29

Light is a critical resource for plant growth and survival, and leaves are designed to capture light

Example of phenotypic plasticity in plants is the adaptation of leaves to sun and shade conditions

Question 30

How can a plant tell whether it will grow in the sun or shade?

Answer 30

Plants produce proteins called phytochrome, a photoreceptor that detects shading by other plants

As white light passes through a plant’s leaves, some wavelengths are absorbed and others are transmitted

Green light is TRANSMITTED (which’s why leaves appear green) and red and blue light is absorbed, so plants growing underneath other plants receive reduced amounts of red light
It’s the reduced ratio of red light to far-red light that elicits a phytochrome response

Question 31

Phytochrome not only detects light quality, but it regulates…

Answer 31

gene expression

When plants receive a lower ratio of red to far-red light, the phytochrome molecule activates a different set of genes

These genes in turn alter morphological, physiological and biochemical characteristics in plants

Question 32

scientific method

Answer 32

Observing outside world
Asking a question about a natural phenomenon that interests us
Hypothesising an explanation for the phenomenon
Testing the hypothesis through a correlational or experimental study
Collecting and analyzing data from the experiment
Creating a conclusion from the experimental data

Question 33

observations

Answer 33

The “hows” and “whys” of nature

Question 34

hypothesis

Answer 34

A tentative answer to the question stemming from your observations

-one or more factors influence the observed phenomenon
-worded in a way that proposes a relationship between one or more factors and the observed phenomenon
-can never be proved only disproved

Question 35

Since we can only disprove a hypothesis, we create a tool, the _______ (H0) that when rejected provides support for our hypothesis, which we refer to as the hypothesis (Ha; aka “alternate hypothesis” )

Answer 35

null hypothesis

Question 36

null hypothesis

Answer 36

Null hypothesis states that the factor you are interested in has no effect on the observed results, while your hypothesis states that it has an effect on the results

-Contrary to hypothesis, null hypothesis proposes NO relationship between the factor being studied and the observed phenomenon and can be seen as the default position when trying to explain the observed phenomenon

-For every hypothesis you make (that something interesting is happening), there will be a corresponding null hypothesis (that nothing interesting is happening)

Question 37

experimental manipulations

Answer 37

Experimental manipulations use artificial manipulations to investigate the relationship between one factor and another

Question 38

correlational studies

Answer 38

Correlational studies use natural variation to investigate the relationship between one factor and another

Question 39

independent variable

Answer 39

The factor being controlled or manipulated by the researcher is the independent variable

Question 40

dependent variable

Answer 40

The phenomenon is the response or dependent variable (the variable that’s usually being measured and is not controlled by researcher)

Question 41

control

Answer 41

A control is a reference to which the results of an experimental manipulation can be compared

-E.g. if we want to investigate the effect of smoking on human lung tissue, we need a control group of non-smokers to compare with a treatment group of smokers
-Controls are important to ensure that the conclusions drawn from an experimental manipulation are biologically valid

Question 42

confounding variables

Answer 42

Confounding variables are factors that the researcher failed to control or eliminate in which can damage the validity of an experiment

Question 43

controlled variables

Answer 43

Controlled variables are variables held constant in a study

Question 44

advantages of a correlational study

Answer 44

1. Less handling time of organisms
2. Systems under study are more likely to be observed in their natural state
   -mere act of manipulation can introduce differences among treatments, which can affect our results and conclusions
3. Represent biologically relevant variation

4.There are situations where experimental manipulation is not practical or ethical

Question 45

advantages of an experimental manipulation

Answer 45

They are more likely to control for confounding variables

We know the direction of causation

Question 46

importance of plant-animal interactions

Answer 46

Plants produce almost all energy available in terrestrial ecosystems

Important energy source for other organisms

Animals that feed on plants receive this energy indirectly

Plants provide shelter and provide survival for most animals

Plants can’t be displaced, animals help them with seed dispersal/reproduction

These can lead to adaptations→leads to diversity

Question 47

positive species interaction

Answer 47

Positive→species benefit from the interaction

Question 48

negative species interaction

Answer 48

interaction is costly for species

Question 49

__________ determines the nature of the interaction (if the costs outweigh the benefits, then the interaction has a negative effect on species)

Answer 49

Net effect

Question 50

competition

Answer 50

When interaction has negative effect on both species →competition

Competition arises when both species require the same resource

Not common between plants and animals (only between animals)

Question 51

mutualism

Answer 51

Mutualism → interactions in which both species benefit
E.g. ant in tree (ant gets shelter, tree gets more resources), pollination

Question 52

consumer-resource interaction

Answer 52

positive effect on one and negative effect on the other

Consumer benefits and the resource suffers a cost

Relationship between predator-prey, parasite-host, herbivore-plant

Question 53

plant herbivore interactions

Answer 53

Organisms feed on foliage, eating entire leaves or portions of them

Only one type of herbivory and different organisms (different feeding modes)

Herbivores can have strong effects on plants
Removal of plant tissue negatively impacts plant’s fitness
-plant feeding reduces amount of resources for photosynthesis, plant growth and production of seeds
-herbivores that consume and kill seeds have a negative effect on plant fitness
-flowers consumed → pollination and reproductive success reduced
-herbivores can also indirectly decrease fitness by transmitting viruses between plants through their mouthparts or saliva

Question 54

plant resistance

Answer 54

plants can resist herbivores through tolerance/defense

Question 55

tolerance

Answer 55

Tolerance is a plant’s ability to to reduce the effects of herbivory on fitness

Plants can tolerate herbivory by physiological responses
e.g. move resources from roots to shoots following herbivory in order to stimulate shoot growth and replace lost tissue

Question 56

defense

Answer 56

Defense is a trait that reduces damage to a plant by herbivores

-3 categories:
Timing of flowering or leaf production
Structural defenses
Chemical defenses

Question 57

Plant can employ more than one defense against herbivores, and they can combine different types of defenses:

Answer 57

plants can have both structural and chemical defenses

Question 58

phenology

Answer 58

study of life cycles of plant and animals in relation to seasonal change

-plants can defend themselves from herbivore damage by producing leaves or flowers when herbivores are least abundant
-may also present flowers or leaves simultaneously instead of sequentially
-this could reduce damage by herbivores if herbivores can’t eat as much of the plant tissue in simultaneous presentation as in sequential presentation

Question 59

trichomes

Answer 59

traps herbivores and prevents them from laying eggs or makes it difficult for them to feed on leaf tissue

Question 60

constitutive defenses

Answer 60

Defenses costly to make so only produced by plants when needed→ constitutive defenses

Question 61

induced defenses

Answer 61

produced or increase their levels of expression following damage by a herbivore