III.+Organisms+and+Populations

toc

=A) Diversity of Organisms (8%) = **i) Evolutionary patterns ** (1) What are the major body plans of plants and animals? Since plants and animals have gotten bigger, they need to get water and nutrients to all of their cells. Diffusion only works in a very small organism. Both plants and animals evolved tube-like structures to transport resources to all parts of the body. We see a xylem and phloem in plants. In animals there are organ systems like digestive and circulatory. Both plants and animals require and produce gas for cellular processes. Both have large surface areas for gas exchange. In plants we see leaves, and in animals there can be things like gills or lungs. Plants and animals also need some structural support against gravity, such as bones.

**ii) Survey of the diversity of life ** (1) What are representative organisms from the Domain Eubacteria, Kingdom Fungi, and Kingdom Protista? Cyanobacteria, also called blue-green algae. Basidiomycetes (Club Fungi): mushrooms Chlorophyta (Green Algae)  (2) What are representative members of the major animal phyla and plant divisions? **Animalia**: Porifera (Sponges) Cnidaria (Jellyfish) Platyhelminthes (Flatworms) Nematoda (Nematodes) Mollusca (Clams) Annelida (Segmented Worms) Arthropoda (Arthropods) (insects, crustaceans) Echinodermata (Echinoderms) (starfish)  Chordata (Chordates) (humans) Bryophyta (Mosses & Liverworts) Lycophyta (Club Mosses) Pterophyta (Ferns) Coniferophyta (Cone-Bearing Trees & Shrubs) Anthophyta (Flowering Plants)
 * Eubacteria: **
 * Fungi:**
 * Protista:**
 * Plantae: **

**iii) Phylogenic classification ** (1) What are the distinguishing characteristics of each group (kingdoms and the major phyla and divisions of animals and plants)? **Animalia**: Porifera (Sponges)  Cnidaria (Jellyfish)  Platyhelminthes (Flatworms)  Nematoda (Nematodes)  Mollusca (Clams)  Annelida (Segmented Worms)  Arthropoda (Arthropods) (insects, crustaceans)  Echinodermata (Echinoderms) (starfish)  ** Plantae: ** Bryophyta (Mosses & Liverworts)  Pterophyta (Ferns)  Coniferophyta (Cone-Bearing Trees & Shrubs)  Anthophyta (Flowering Plants)
 * No definite symmetry.
 * Body multicellular, few tissues, no organs.
 * Cells and tissues surround a water filled space but there is no true body cavity.
 * All are sessile, (live attached to something as an adult).
 * Reproduce sexually or asexually, sexual reproduction can be either gonochoristic or hermaphroditic.
 * Has no nervous system.
 * Has a distinct larval stage which is planktonic.
 * Lives in aquatic environments, mostly marine.
 * All are filter feeders.
 * Often have a skeleton of spicules.
 * Radially Symmetrical.
 * Body multicellular, few tissues, some organelles.
 * Body contains an internal cavity and a mouth.
 * Two different forms exist, medusa and polyp
 * Reproduction is asexual or sexual.
 * Has a simple net like nervous system.
 * Has a distinct larval stage which is planktonic.
 * Lives in aquatic environments, mostly marine.
 * Mostly carnivorous otherwise filter feeders.
 * May have a minimal skeleton of chiton or calcium carbonate.
 * Bilaterally symmetrical.
 * Body having 3 layers of tissues with organs and organelles.
 * Body contains no internal cavity.
 * Possesses a blind gut (i.e. it has a mouth but no anus)
 * Has Protonephridial excretory organs instead of an anus.
 * Has normally a nervous system of longitudinal fibres rather than a net.
 * Generally dorsoventrally flattened.
 * Reproduction mostly sexual as hermaphrodites.
 * Mostly they feed on animals and other smaller life forms.
 * Some species occur in all major habitats, including many as parasites of other animals.
 * Bilaterally symmetrical, and vermiform.
 * Body has more than two cell layers, tissues and organs.
 * Body cavity is a pseudocoel, body fluid under high pressure.
 * Body possesses a through gut with a subterminal anus.
 * Body covered in a complex cuticle.
 * Has a nervous system with pharyngeal nerve ring.
 * Has no circulatory system (no blood system)
 * Reproduction normally sexual and gonochoristic.
 * Feed on just about everything.
 * Live just about everywhere, many species are endoparasites.
 * Bilaterally symmetrical.
 * Body has more than two cell layers, tissues and organs.
 * Body without cavity.
 * Body possesses a through gut with mouth and anus.
 * Body monomeric and highly variable in form, may possess a dorsal or lateral shells of protein and calcareous spicules.
 * Has a nervous system with a circum-oesophagal ring, ganglia and paired nerve chords.
 * Has an open circulatory system with a heart and an aorta. [[image:http://www.earthlife.net/inverts/images/clipart/blank.gif width="100" height="82" align="right"]]
 * Has gaseous exchange organs called ctenidial gills.
 * Has a pair of kidneys.
 * Reproduction normally sexual and gonochoristic.
 * Feed a wide range of material.
 * Live in most environments.
 * Bilaterally symmetrical and vermiform.
 * Body has more than two cell layers, tissues and organs.
 * Body cavity is a true coelom, often divided by internal septa.
 * Body possesses a through gut with mouth and anus.
 * Body possesses 3 separate sections, a prosomium, a trunk and a pygidium.
 * Has a nervous system with an anterior nerve ring, ganglia and a ventral nerve chord.
 * Has a true closed circulatory system.
 * Has no true respiratory organs.
 * Reproduction normally sexual and gonochoristic or hermaphoditic.
 * Feed a wide range of material.
 * Live in most environments.
 * Bilaterally symmetrical (in most cases).
 * Body has more than two cell layers, tissues and organs.
 * Body cavity a true coelom.
 * Most possesses a through straight gut with an anus (in most cases).
 * Body possesses 3 to 400+ pairs of jointed legs.
 * Body possesses an external skeleton (in most cases).
 * Body is divided in 2 or 3 sections.
 * Nervous system includes a brain and ganglia.
 * Possesses a respiratory system in the form of tracheae and spiracles (in most cases).
 * Possesses a open or lacunnar circulatory system with a simple heart, one or more arteries, and no veins, (in most cases).
 * Reproduction normally sexual and gonochoristic, but can be parthenogenetic.
 * Feed on everything.
 * Live everywhere.
 * Possess 5-rayed symmetry, mostly radial, sometimes bilateral.
 * Body has more than two cell layers, tissues and organs.
 * Body cavity a true coelom.
 * Most possesses a through gut with an anus.
 * Body shape highly variable, but with no head.
 * Nervous system includes a circum-oesophageal ring.
 * Has a poorly defined open circulatory system.
 * Possesses a water vascular system, which hydraulically operates the tube feet or feeding tentacles.
 * Without excretory organs.
 * Normally possesses a subepidermal system of calcareous plates
 * Reproduction normally sexual and gonochoristic.
 * Feeds on fine particles in the water, detritus or other animals.
 * All live marine environments.
 * Non-vascular
 * Enclosed reproductive systems
 * Reproduce via spores
 * Spend most of their lives as haploid
 * Have xylem and phloem, making them vascular
 * No seeds, leaves, or flowers
 * Reproduce via spores
 * Gymnosperm
 * Cone bearing
 * Seeds
 * Vascular tissue
 * Woody plants
 * Seeds enclosed within ripened ovary

**iv) Evolutionary relationships **  (1) What is some evidence that organisms are related to each other?

Evidence that demonstrates that organisms are related to each other are homologous structures. Homologous structures are structural similarities in an organism’s body such as the similarities in the forelimbs of a human, bat, cat and whale. They are similar in that the bones are attached in similar ways and the bones are proportionally similar.

Another example is the similarities between DNA of two organisms; DNA is the “blueprint” for all organisms on earth (which supports the theory that all organisms descend from a common ancestor). Scientists can compare the DNA sequences between organisms and the more similar DNA they have the more closely they are related.

Another type of homologous structure is the vestigial structure. These further show that populations have diverged from a single common ancestor. These vestigial structures are usually of little importance to specific organisms, but their presence is important because it helps scientists trace ancestry. Examples of this are clearly displayed in the forelimbs of various types of mammals. <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">2) How do scientists study evolutionary relationships among organisms?

Scientists look for similarities in behavior, coloration, body structure, and genetic makeup.

they can also look at fossils to find ancestral species which shows relationships among many organisms <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">(3) How is this information used in classification of organisms? Scientist pick animals that are similar, like a house cat and ocelot or an African elephant and an Asian elephant, place them in groups and further break them down into specific species.

Scientists break the organisms into groups called domains, kingdoms, phylums, classes, orders, families, genuses, and species. They use the information, such as body structure and genetic makeup, to place the organisms into broad groups, such as the domain archaea or bacteria. They then find similar organisms and group them into more specific groups, all the way down into the correct genus. =<span style="font-family: Arial,Helvetica,sans-serif;">B) Structure and Function of Plants and Animals (32%) =

<span style="font-family: 'Times New Roman',Times,serif;">**<span style="font-family: Arial,Helvetica,sans-serif;">i) Reproduction, growth, and development ** <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">(1) What patterns of reproduction and development are found in plants and animals and how are they regulated? in plants: sporophyte and gametophyte generations alternate in the life cycles of plants. flowers are specialized shoots bearing the reproductive organs of the angiosperm sporophyte. male and female gametophytes develop within anthers and ovaries and pollination brings the two developed parts together. in addition, to prevent self pollination, plants have various mechanisms. double fertilization gives rise to the zygote and to the endosperm. the ovule develops into a seed containing an embryo and a supply of nutrients. the ovary develops into a fruit that is special for seed dispersal. evolutionary adaptations of seed germination contribute to the seedling survival. plants also reproduce asexually. in animals: both asexual and sexual reproduction occurs in the animal kingdom. diverse mechanisms of asexual reproduction enable animals to produce identical offspring rapidly. reproductive cycles and patterns also vary among animals.internal and external fertilization depends on mechanisms ensuring that the mature sperm encounters the mature egg of the same species. species with internal fertilization usually produce fewer zygotes but prove more parental care than species with external fertilization. in human reproduction, spermatogenesis and oogenesis involve meiosis. spermatogenesis is the development of the sperm cells and then oogenesis is the development of the female reproductive cell. hormones in humans regulate reproduction.

(2) What is the adaptive significance of alternation of generations in the major groups of plants?

Also... The dominant form of bryophtes is the gametophtye- in fact, the sporophyte generation is actually dependent on it. This actually makes sense if you look at ferns-- they aren't very big individually, they're small, so they need to produce more and more of them in order to increase overall surface area. However, as plants evolved, they adapted a vascular system, the sporophyte generation became dominant. With a vascular system it can grow taller, but growing takes time, so the sporophyte became dominant instead of the gametophyte. And, reducing the dominance of the gametophyte is part of why plants became successful on land.
 * alternation of generations ** is what the life cycle of plants is referred to as. There are two distinct phases: gametophyte phase (haploid) and sporophyte phase (diploid). A haploid plant of the gametophyte generation produces gametes by mitosis. Two gametes combine to produce a zygote, which develops into a diploid plant of the sporophyte generation. This sporophyte produces spores by meiosis, which germinate and develop into a gametophyte of the next generation.

(1) How does the organization of cells, tissues, and organs determine structure and function in plant and animal systems? Cells are the basic unit of life. Tissues are groups of similar cells that perform a particular function. Organs are made up of groups of tissues that perform related functions.
 * <span style="font-family: Arial,Helvetica,sans-serif;">ii) Structural, physiological, and behavioral adaptations **

In plants and in most animals, cells are specialized, so they do perform unique functions. Take for example the mesophyll cells in plants. These are the cells that perform photosynthesis, and it makes sense that these cells are the ones that do because they are present on the leaves of a plant. The leaves provide a giant amount of surface area that absorbs a lot of light from the sun. By making the leafs accessible to the energy source, the mesophyll cells receive their light energy to convert to chemical energy for the plant's wellbeing. (3) How do the organ systems of animals interact? The respiratory system gets rid of waste (CO2) and provides the body with more oxygen, which in turn gets binded to by the hemoglobin in blood. The heart pumps the blood around the body because of the circulatory system, which takes o2 to places like muscles for respiration. We breathe in oxygen which undergoes gas exchange in the lungs; then co2 undergoes gas exchange in the lungs, and gets breathed out. The brain acts as the control center for all of the organ systems that make up our bodies. Its neurons control both our voluntary muscle movement and our involuntary muscle movement (like peristalsis in the digestive system, circulation of blood flow for oxygen, etc.) Organs are so interdependent that the damage of one can result in the failure of another until all organ systems shut down. The nervous system is so important that if it shuts down, all of the organ systems will fail as well. (4) What adaptive features have contributed to the success of various plants and animals on land? In order to live on land, various plants and animals developed features such as a vascular system, support against gravity, protection against desiccation by an outer tough covering, internal fertilization and ability to absorb required gasses from gas-phase atmosphere. Animals had changes in mouth parts and foraging habits. The evolution made it so pants can convert carbon dioxide into sugar and other essential things that are needed by animals. The animals can eat the plants and convert the sugars into energy. (1) What are the responses of plants and animals to environmental cues, and how do hormones mediate them? During a drought, the hormone Abscicic Acid causes the stomates to close. If the plant begins to wilt, ABA will be immediately produced and the stomates will be rapidly closed. Abscicic Acid or ABA also slows growth and makes sure that the seed stays dormant and only germinates when there is the right amount of light, nutrients, and moisture for the seedling to survive. In maturing seeds the levels of ABA are very high because the seed shouldn't germinate just yet. It needs to wait a bit longer. Gibberellins-when it rains and the seed imbibes water the release of gibberellins from the seeds embryo signals the seed to break dormancy and germinate.
 * <span style="font-family: Arial,Helvetica,sans-serif;">iii) Response to the environment **
 * PLANTS: **

Ethylene is produced in plants in response to environmental stresses, such as drought, flooding, injury, mechanical pressure, or infection. An example of mechanical pressure is when a seedling is pushing upward through the soil and it hits a rock. This stresses the delicate tip and produces ethylene. The ethylene causes a triple response to take place and the plant is able to maneuver around the rock and become stronger.

** ANIMALS ** When you intake too much alcohol, the hormone ADH is inhibited. So, your body excretes a lot of urine, but it's all concentrated because ADH controls the absorption of water.

Most animal’s reproductive cycles are regulated by the changing seasons, and reproductive cycles are controlled by hormones. Many mammals ovulate at the time of year when fertilization will result in the young being born in the spring when chances of survival are greatest.

AND, when humans are in a stressful situation, our bodies release epinephrine which increases our heart rate, etc. Ex: you're being chased by a bear, and you find you can run much faster than you can in PE class. ( The "fight or flight" hormone) Nonepinephrine helps regulate your body systems and gets them back to normal after that scary run-in with the bear.

=<span style="font-family: Arial,Helvetica,sans-serif;">C) Ecology (10%) = egology definitons: ecology- study of interactions of organisms with their physical environment and with each other population- group of individuals of one species living in one area who have teh ability of interbreeding and interacting with each other community- all organisms living in one area ecosystem- all organisms in a given area as well as the abiotic factors biosphere- global ecosystem

<span style="font-family: 'Times New Roman',Times,serif;">**<span style="font-family: Arial,Helvetica,sans-serif;">i) Population dynamics ** <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;"> (1) What models are useful in describing the growth of a population?


 * Logistic Growth Model: ** “realistic” version of population growth: takes into account that resources are limited and that every population has a carrying capacity. The graph has a distinct S shape.

This model show that as the rate of increase in population reaches zero, carrying capacity is being reached. To clarify, carrying capacity is the largest population that the environment can sustain.

The equation for the Logistic Growth model is - dN/dt = r(max)N((K-N)/K)
 * r(max) is the max per capita rate of increase (intrinsic rate of increase)
 * K is the carrying capacity
 * N is the population size
 * t is time


 * Exponential Growth Model: ** idealistic model of population growth: assumes that organisms can reproduce without problems and that there is no competition for resources/ that resources aren’t limited. The graph has a distinct J curve.

The equation for this model is dN/dt = r(max)N
 * r(max) - intrinsic rate of increase
 * N- population size

There is also Zero population growth, which doesn't have a model, but is rather important. This is when the death rates and birth rates are equal. This doesn't mean that there is no birth and no death, it just means that the amounts of births and deaths equal eachother out perfectly.

<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">(3) How do organisms affect the cycling of elements and water through the biosphere?

Animals eat organic molecules and then excrete some of them out. These are then absorbed by soil, which is saturated with water, which then evaporates. Primary producers then used the CO2 and water in the atmosphere to perform photosynthesis. Primary consumers then eat the primary producers, who in part are eaten by secondary and then tertiary consumers. All these animals then excrete nutrients back into the earth.

Biotic (living) factors affect the community and ecosystem by either preying upon organisms, being preyed upon as a food source for other organisms, or providing an environment for a community to live in. Biotic factors can also destroy ecosystems through their consumption of resources or general destruction for their own benefit (think humans and global warming/cutting down the rainforest/killing for fur). Abiotic factors can be barriers or conditions in which organisms can or can not thrive, such as a mountainous terrain being unideal for prairie animals or tropical temperatures being unideal for penguins to live in.

definitions- biotic: biotic factors are all the living components of an ecosystem abiotic: nonliving factors- temperature, water, sunlight, wind, rocks, and soil

(1) In which ways are humans affecting biogeochemical cycles?
 * <span style="font-family: Arial,Helvetica,sans-serif;">iii) Global issues **

Global warming- the addition of extra CO2 to the ozone layer as well as deforestation are both ways humans are affecting biogeochemical cycles. Also, the excessive killing of animals is destructive to the food/energy cycle since many consumers and secondary producers are having their numbers decreased. Additionally, when we use fossil fuels, we release pollutants into the atmosphere, which turn into acid and lower the pH of rain (aka acid rain). Then this acid rain harms and kills organisms in lakes, rivers, etc.

<span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">(2) How is population size regulated by abiotic and biotic factors? Population size is regulated by the biotic factors of: disease, parasitism, limited food supply and predation, and competition. Disease, parasites and predation limits the size of a population through death. Limited food supply regulates the size of a population in that the amount of food corresponds to the size of the population. When organisms compete for food and space it can limit population size. Abiotic factors create an environment that could be limiting to the organism. For example, the forests in Madagascar that are surrounded by steep sharp mountains limit the size of the area available for habitation, limiting the size of the populations of organisms that live there. Other limiting abiotic factors are Chemical factors like: water, oxygen, salinity, pH, or soil nutrients and Physical factors like: temperature, light, soil structure, fire, and moisture.

(1) How is energy flow through an ecosystem related to trophic structure (trophic levels)? <span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">There are trophic levels like producer, primary consumer, secondary consumer and tertiary consumer. If you were to arrange these in a pyramid based on biomass, the greatest would be at the bottom, because they are the producers. This is because of the second law of thermodynamics. When biomass and energy is transferred from one level to another, there is a loss along the way. Energy transfer isn't 100% efficient. For example, when a cow eats grass, it gets some energy from it to build muscle and bone, but a lot of the energy is lost as heat. Because of this, the cow needs to eat more grass (in mass) than the cow actually contains. <span style="color: #800018; font-family: Arial,Helvetica,sans-serif;"> (2) How do elements (e.g. carbon, nitrogen, phosphorous, sulfur, oxygen) cycle through ecosystems? (3) How do organisms affect the cycling of elements and water through the biosphere?
 * <span style="font-family: Arial,Helvetica,sans-serif;">ii) Communities and ecosystems **<span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">

<span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">By consuming and excreting them in different areas

<span style="color: #ff00d9; font-family: Arial,Helvetica,sans-serif;">Water Cycle: Water evaporates from plants via transpiration. Carbon Cycle: Cellular Respiration adds CO2 to the air, and photosynthesis removes it from the air. Also, when we burn fossil fuels, we add even more CO2 into the atmosphere. Nitrogen Cycle: Nitrogen-fixing bacteria convert nitrogen into ammonium, nitrifying bacteria convert ammonium into nitrates, and denitrifying bacteria convert nitrates into nitrogen. <span style="color: #800018; font-family: Arial,Helvetica,sans-serif;">

(4) How do biotic and abiotic factors affect community structure and ecosystem function?

Abiotic factors, such as sunlight or wind, may be more prevalent in some areas than in others. So in an area where wind blows away food that scavengers would eat, these scavengers will die, since an abiotic factor affected the enviornment and made it so no more food was avaliable. And now, decomposers have more to eat, since more organisms are dead, and now the communty structure and ecosystem are much different from earlier. A biotic factor that can affect community structure and ecosystem function would be like prey-predators. Biotic factors like more predators would force the prey population to do something to protect itself.

(1) In which ways are humans affecting biogeochemical cycles? <span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">Humans accelerate natural biogeochemical cycles when we extract elements from their reservoirs or sources, and deposit them back into the environment. An example is that humans altered the carbon cycle by extracting and combusting billions of tons of hydrocarbons in fossil that were buried deep in the Earth's crust. Also we clear vegetation, which stores carbon. Half of the extra carbon produced is taken up by plants and the oceans, and the other half remains in the atmosphere. Humans also have altered the nitrogen and phosphorus cycles by adding these elements to croplands, like with fertilizers. These contribute to over-fertilization of aquatic ecosystems when excess amounts are washed into local waterways.
 * <span style="font-family: Arial,Helvetica,sans-serif;">iii) Global issues **<span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">

humans often pollute resources which makes in unusable or we consume too much of certain resources

Biomes- very large areas of the earth whose distribution depends on teh amount of rainfall and the temperature in the area, each is characterized by different vegetation and animal life
 * marine- largest biome, most stable, provides most of the earth's food and oxygen, divided into regions depending on amount of sunlight it recieves
 * tropical rain forest- accounts for more than 20 percent of the earth's net carbon fixation (food production), most diverstiy of species
 * desert- very little rainfall, most extreme temperature fluctuations, most organisms are adapted to hot,arid conditions (CAMplants)
 * temperate grasslands- low total rainfall, have mainly grazing animals
 * temperate deciduous forest- trees drop their leaves in winter, rich soil due to decompositon of leaves
 * conifer forest (taiga)- dominated by conifer (evergreen) forests, very cold winters, largest terrestrial biome, heavy snowfall
 * tundra- permafrost (frozen subsoil), referred to as the frozen desert