Chapter 4 Free Response

Describe each of the following immune responses, including

identifying whether is it innate or adaptive, identifying what

initiates the response, what is targeted by the response, and

identifying a taxon that exhibits this type of response.

PAMP-triggered Immunity

Systematic Acquired Response (SAR)

Hemocyte Response

Humoral Immune Response

Cell-mediated Response

PAMP-triggered Immunity -

1) innate immunity

2) recognition of PAMPs by pattern recognition on host cells

3) bacteria and fungi based on their PAMPs

4) Plants

Systematic Acquired Response (SAR) -

1) Innate

2) local infection or wounding in plants

3) broad protection against infections by pathogens

4) plants

Hemocyte Response -

1) innate

2) pathogens or tissue damage

3) pathogens

4) invertebrates (arthropods)

Humoral Immune Response -

1) adaptive

2) detection of antigens by B cells

3) bacteria, viruses, toxins

4) vertebrates

Cell-mediated Response -

1) adaptive

2) antigens on infected or abnormal host cells by T cells

3) intercellular pathogens

4) vertebrates

Draw and label a generalized sexual life cycle for each

of the following:

§ Animals

§ Plants

§ Fungi

Your diagram should include meiosis, fertilization, at least one

correct place where mitosis occurs in the life cycle, gametes,

spores (if applicable), zygote, and multicellular organism. Your

diagram should indicate which part of the life cycle is haploid (n)

and which part is diploid (2n)

Briefly describe (1-2 sentences) what is meant by alternation of

generations. What is a sporophyte? What is a gametophyte? Be

sure to include whether each is haploid or diploid, what type of

cells it produces, and whether those cells are produced through

mitosis or meiosis. Explain which is the dominant life stage for

each of the following plant groups:

§ Non-vascular plants

§ Seedless vascular plants

§ Seed plants

Alternation of generations: It is a life cycle in plants in which a multicellular haploid gametophyte generation alternates with a multicellular diploid sporophyte generation, each producing the other through reproduction.

Sporophyte: the diploid (2n) stage that produces haploid spores by meiosis

Gametophyte: the haploid (n) stage that produces haploid gametes by mitosis

Non vascular plants Seedless: gametophyte

Seedless vascular plants: sporophyte

Seed plants: sporophyte

Briefly describe the difference between primary and secondary

growth in plants. What is the main site of cell division for primary

growth in roots? What is the primary site of cell division for

primary growth in shoots? What is one function of the root cap?

What do leaf primordia develop into? What do axillary buds

develop into? What is the main site for secondary growth? Where

are new layers of xylem and phloem produced? Describe the major

developmental difference between the two groups of angiosperms,

monocots and eudicots

1) primary growth - increases length

Secondary growth - increases thickness

2) roots: apical meristem

Shoots: shoot apical meristem

3) root caps protect the apical meristem and eases the root movement

4) leaf primordial develops into mature leaves

5) auxiliary buds develop into branches and flowers

6) lateral meristems (vascular and cork cambiums)

7) vascular cambium xylem (inside) phloem (outside)

8) Monocots - one cotyledon (vascular bundle)

Eudicots - two cotyledon (vascular bundles in a ring)

In each of the two major groups of seed plants

(gymnosperms and angiosperms), where would you find

the male and female gametophytes? What occurs

during double fertilization in angiosperms? What is

endosperm? Explain why seeds represent an adaptation

to terrestrial life

1) gymnosperms:

• male gametophyte: in pollen grains

• Female gametophyte: in ovules

Angiosperms:

• male gametophyte: pollen grains

• Female gametophytes: embryo sac inside the ovule

2) double fertilization:

• One sperm fertilizes the egg → forms the zygote

• Another sperm fuses with two polar nuclei → forms triploid endosperm

3) endosperm:

• nutrient-rich tissue (usually triploid) that provides food for the embryo

• Unique to angiosperms due to double fertilization

4) seeds are an adaption

• protect the embryo from drying out

• Provide stored food for early growth

• Allow dispersal over long distances without needing water for fertilization

• Can remain dormant until conditions are favorable

Name and describe the four stages of embryonic development

in animals. What is the major difference between diploblasts and

triploblasts? What is the major difference between protostomes

and deuterostomes? Provide an example of an organism that

belongs to each of those four groups

1) fertilization:

• sperm and egg fuse → zygote forms

• Restores the diploid chromosome number

2) cleavage:

• rapid mitotic divisions of the zygote

• Produces a morula (solid ball of cells) and then a blastula (hollow ball of cells)

3) gastrulation

• cells rearrange to form germ layers (ectoderm, mesoderm, endoderm)

• Blastopore (opening) forms

4) organogenesis

• germ layers differentiate into tissue and organs

• Nervous system, muscles, and other organs stat forming

Diploblasts vs triploblasts

Diploblasts: 2 germ layers

Tripoblasts 3 germ layers

Protostomes vs deuterostomes

Protostomes:

• Blastopore: becomes mouth first

• Cleavage: spiral, determinate

• Coelom foundation: splitting of mesoderm

Deuterostome:

• Blastopore: becomes anus first

• Cleavage: radial, indeterminate

• Coelom foundation: out-pocketing of archenteron

Examples of each group

Diploblasts: jellyfish

Triploblasts: earthworm

Protostomes: grasshopper

Deuterostomes: human

Define ecology. name and briefly describe (1-2 sentences each) the six levels that compose the hierarchical organization of ecological research

Ecology:is the study of interactions between organisms and their environments.

1) organismal

2) population

3) community

4) ecosystem

5) landscape

6) biosphere

escribe four different factors that limit species

distributions with a specific example of how they limit

species distributions. State whether each of the four

factors you chose is an abiotic or biotic factor and

include at least one of each. Several of these factors also

influence population dynamics. Provide definitions for

population and population dynamics

1) temperature (abiotic)

• many species can only survive within a certain temperature range

• Tropical plants will freeze in cold climates

2) water availability (abiotic)

• organisms need water for survival

• Cacti are adapted to deserts

3) food availability (biotic)

• food availability limits where organisms can live

• Giant pandas only live where bamboo grows cause it solely relies on it for food

4) predation (biotic)

• predators prevent prey species from living in certain areas

• Sea urchin populations are limited where predators like otters are abundant

Definitions:

• Population:
  A group of individuals of the same species living in the same area at the same time.

• Population dynamics:
  The study of how and why populations change over time, including factors like birth rates, death rates, immigration, and emigration.

Define population density and dispersion. Name and

describe three types of dispersion patterns that can be

observed in nature. For one of these patterns, give

examples of two different processes that could have led

to the same pattern. What two factors add individuals to

a population? What two factors remove individuals from

a population? What is a metapopulation

• Population density:
  The number of individuals of a species per unit area or volume (e.g., per square kilometer).

• Dispersion:
  The pattern of how individuals are spaced within a population.

Three types of dispersion patterns

1) Clumped dispersion

• individuals grouped together in patched

• Common when resources are unevenly distributed

2) uniform (even) dispersion

• individuals are spaced evenly apart

• Competition or territorial behavior

3) random dispersion

• individuals are distributed unpredictably

• When resources are abundant and interactions between individuals are minimal

Two processes leading to to the same pattern (clumped dispersion)

• patchy resources: individuals gather where food or water is available

• Social behavior: individuals stay together for protection, mating, or cooperation

Factors affecting population size

1) add individuals

• births (natality)

• Immigration (individuals moving into the population)

2) Remove individuals

• deaths (mortality)

• Emigration (individuals leaving the populations)

Metaopulation

• A metapopulation is a group of spatially separated populations of the same species that interact through migration.

• Local populations may go extinct, but the overall metapopulation persists because individuals can recolonize empty areas.

Write the equation and draw a simple graph for the exponential

growth model. You do not need to have numbers on your axes, but

you should know what is represented on the vertical, or y-axis, and

what is represented on the horizontal, or x-axis, and you should be

able to explain the shape of the curve. Thinking about what adds

individuals to a population, why is the curve J-shaped – that is, why

does the curve start out relatively flat and then get steeper and

steeper as you move to the right? What are the two factors that

influence the population growth rate (dN/dt) in the exponential

growth model? What is the main assumption of the exponential

growth model related to resource availability? How do larger

values of r influence population growth

dN/dt = rN

Y-axis: population size

X-axis: time

Shape: j-shaped curve

• is j shaped because the fewer in the population the fewer the reproduction, but the more is in the population the more is produces

Population size and intrinsic rate of increase

Unlimited resources And no environmental resistance

Larger r → faster population growth

The curve becomes steeper more quickly

Write the equation and draw a simple graph for the logistic growth

model. You do not need to have numbers on your axes, but you should

know what is represented on the vertical, or y-axis, and what is

represented on the horizontal, or x-axis, and you should be able to

explain the shape of the curve. Why is the curve S-shaped – that is, why

does the curve start out relatively flat, get steeper, and then become flat

again? How does the logistic growth model equation differ from the

exponential growth model equation? What is carrying capacity (K)?

What happens to the equation (and to the population growth rate,

dN/dt), when N = K? What happens when N is larger than K? What

happens when N is much, much smaller than K? When is the overall

population growth rate the highest in the logistic growth model? Why?

(Hint: think about what adds individuals to a population and what

happens in terms of resource availability as the population grows)

dN/dt = rN (K-N /K)

• N = population size

• r = intrinsic rate of increase

• K = carrying capacity

• dN/dt = population growth rate

• Y-axis: Population size (N)

• X-axis: Time (t)

Shape: S-shaped (sigmoidal curve)

• Beginning is flat cause of small population

• Middle is steep due to reproduction

• End becomes flat because sources become limited

How it differs from exponential growth

• Exponential: dNdt=rN (no limits)

• Logistic: includes (K−N/ K), which reduces growth as N approaches K

Carrying capacity (K)

• The maximum population size the environment can sustainably support.

• What happens at different values of N?

  • When N = K:

    K−NK=0⇒dN/dt=0KK−N​=0⇒dN/dt=0

    → Population stops growing (stable).

  • When N > K:

    (K−N)<0⇒dN/dt<0(K−N)<0⇒dN/dt<0

    → Population decreases (too many individuals for available resources).

  • When N ≪ K (much smaller than K):

    K−NK≈1KK−N​≈1

    → Growth is nearly exponential (resources abundant).

When is population growth rate highest?

• When N ≈ K/2

Why?

• There are enough individuals reproducing (large N)

• But resources are still abundant (not yet limited)

• This creates the maximum balance between reproduction and resource availability, leading to the fastest growth.

What is demography? What does a life table

summarize? Why do demographers typically consider

females only when constructing a life table? How is

reproductive output measured? Why might the age of

individuals be important to consider when measuring

reproductive rates

Demography

• The study of the size, structure, and dynamics of populations over time, including birth rates, death rates, and age distribution.

Life table

• A life table summarizes:

  • Survivorship (how many individuals survive to each age)

  • Mortality rates (death rates at different ages)

  • Often also includes reproductive output by age

Why females are typically used

• Females are usually the limiting factor in reproduction because they invest more energy in producing offspring (eggs, pregnancy, care).

• Tracking females gives a more accurate estimate of population growth potential.

How reproductive output is measured

• Measured as the average number of female offspring produced per female at each age (often called age-specific fecundity).

Why age matters for reproductive rates

• Individuals typically:

  • Do not reproduce when very young

  • Reach a peak reproductive age

  • Have declining reproduction as they age

• So, the age structure of a population strongly affects overall population growth.

  • Example: A population with many individuals in reproductive age will grow faster than one with mostly older individuals.

Draw the basic shape of a Type I, Type II, and Type III

survivorship curve including the axis labels. What does

each type of curve tell you about the number of

individuals surviving in a population throughout an

organism’s life span? Provide an example of an organism

that exhibits each type of survivorship curve

• Y-axis: Number of survivors (often shown as % surviving)

• X-axis: Age

Type 1

• high survival through early and middle ice

• Most individuals die at old age (humans)

Type 2

• constant death rates throughout life

• Equal chance of dying at any age (birds)

Type 3

• very high mortality early life

• Few individuals survive to adulthood, but those who do live longer (oysters)