Bio 110 lab practical

Echinoderms

-A deuterostome -echinoderms are slow moving or immobile animals that live on the sea bottom. The most familiar echinoderm is the sea star. Others include sea urchins, sand dollars, sea cucumbers and sea lilies. -Echinoderms are so named because of their skin. The skin is covered with bumps or spines that project from a calcium-rich internal skeleton. The word echinoderm is derived from the Greek terms echino (spiny) and derma (skin) -these animals have coeloms containing well-developed digestive and reproductive organs. -Echinoderms are brainless, but they have nerve networks. -the hallmark of echinoderms is a water-vascular system that allows echinoderms to move and gather food.

Logistic growth

-Logistic growth occurs in environments where various factors restrict growth. Factors like resource and space limitations, competition or predation may limit population growth. These restrictive factors influence the carrying capacity (K) of a given environment. -the rate of increase is influenced by how large N is in comparison to K. -there are three phases in logistic growth: lag phase, log phase, and stationary phase.

Flatworms

-a non-molting protostome aceolomate -Flatworms are the first to show more than tissue grade level of organization. -both excretory and reproductive organs are present. -flatworms have muscles and nerve cells. The digestive cavity, if present, is still primitive; i.e., most digestion occurs intracellularly. -because these animals are thin and flat, each body cell is close enough to an environmental source of oxygen and a sink of carbon dioxide and other wastes for diffusion to handle the job of gas exchange. -the life cycles of some of these worms are complex and involve both asexual and sexual propagation. -the example of a flatworm in lab was called a planaria.

Rotifers

-a non-molting protostome pseudocoelomate -the members of this group are more structurally complex than the flatworms. -these organisms have complete body cavities and complete digestive systems that take in food at one end, break it down, and push the unused stuff out the other end. -rotifers are abundant in fresh water. Although multicellular, they are often no larger than a single-celled paramecia. -Rotifers are free-living and sweep food into their digestive tracts with cilia. -the rotifers shown in class were called Philodina.

Marchantia

-a nontracheophyte, it is a liverwort -the gametophyte is more prominent than the sporophyte, and is lobe-shaped

Leeches (non-molting protostome coelomates)

-about three-quarters of leeches are blood suckers; the rest are not parasitic to humans, but instead prey upon worms, snails, and insect larvae. -Blood-sucking leeches have numerous adaptations -leeches may painlessly slice open a section of thin skin on a victim and secrete various substances into the wound, like the anti-clotting substance hirudin, to ensure continuous blood flow.

green plants

-all green plants are eukaryotic autotrophs that use chlorophylls a and b to carry out photosynthesis. -all plant cells have cell walls made of cellulose. -Plants follow a unique life cycle consisting of two alternating phases. -in order to reproduce, plants (like animals) make gametes: eggs and sperm.

chordates

-deuterostomes -have notochords. -have pharyngeal arches, pouches and slits that aid in gas exchange -have a hollow dorsal nerve tube. -some chordates are invertebrates; meaning they have no backbones. The remainder of chordates, vertebrates, do have backbones. -examples of chordates: jawless fish (lampreys), perch and sea horses, frogs and newts, turtles, snakes, lizards, sparrows, and humans.

earthworms (non-molting protostome coelomates)

-earthworms are oligochaete worms. -have no well developed head and few setae. -the burrowing of earthworms has positive effects on soil. The burrows improve soil drainage and aeration.

how do sponges get their energy

-like all animals, sponges are heterotrophic and must acquire their nutrients from something else. -the flagellated cells of a sponge help circulate water through the perforated body wall and out the osculum. As the water moves, it brings along food particles. The flowing water also delivers oxygen to the sponge and carries away wastes, such as carbon dioxide and ammonia.

Arthropods

-molting coelomate protostomes -Arthropods comprise the largest animal phylum because it contains the insect species. Also includes crustaceans like crab, crayfish and shrimp; and Chelicerates like spiders, scorpions and horseshoe crabs. -arthropods have paired, jointed appendages. -They are completely covered by an external skeleton called an exoskeleton made of chitin. Although useful, an exoskeleton has no use for growth so it must be shed during molting and later be recreated in a larger size. -arthropods have segmented bodies. The segments fall into three regions: the head, the thorax and abdomen. -arthropods have open circulatory systems.

nematodes

-molting pseudocoelomate protosomes -Nematodes are also called roundworms. -can live in many different places: on land, at sea, in fresh water, in polar regions, deserts and hot springs. they are very common. -There are free-living and parasitic roundworms. -Some nematodes are troublesome to cultivated plants; they may damage plants by blocking the flow of water and soil nutrients in xylem. -Other nematodes like Trichinella, Ascaris, hookworms, pinworms and filaria worms are parasitic on humans.

Annelids

-more non-molting protostome coelomates -This phylum contains multiple classes: earthworms, marine worms, and leeches. -the annelids are segmented worms, i.e., they externally appear to be constructed of similar subunits arranged one after another from head to tail. -the degree of internal segmentation varies: the earthworms tend to have the greatest degree of internal segmentation and the leeches the least.

mollusks

-non-molting protostomes coelomates -mollusks include such creatures as snails, clams, squids and octopuses. -the soft parts of a mollusk consist of a foot, visceral mass and a mantle.

Poriferans

-sponges -poriferans are aquatic and most inhabit the oceans -the basic body plan of a sponge is a three-layered perforated sac, consisting of an outer epidermis, a jelly-like middle layer sprinted with amoeboid cells, and an inner layer composed of cells fitted with flagella. -the cells of a sponge are not organized into a tissue. -sponges are multicellular, but their cells lack tissue-level organization.

sponge skeletons

-sponges have skeletons, the composition of which is the basis of sponge classification. Some skeletons are made of calcium, others of silicon, others of protein.

marine annelids

-the marine annelids are called polychaete worms. -they have easily discernible heads and antennae. -each body segment projects locomotor appendages that have many stiff. bristles called setae. The term polychaete refers to these many bristles. -in lab the example for marine annelids was clamworms (Nereis)

lycophytes

-tracheophyte plants -lycophytes, the club mosses, have roots, stems, and leaves as well as a vascular system to provide transport. The leaves of lycophytes (called lycophylls) are structurally different than the leaves of fern and seed plants (called euphylls). -the lycophylls have only one unbranched vein; euphylls have branched veins. -the prominent sporophyte produces a club-shaped reproductive structure called a strobilus at the top of the plant that produces spores. -The example of a lycophyte used in lab was Selaginella

Predation

A predator gains energy and matter from its prey. Predators seek to capture prey and prey seek to avoid predators. Simple concept, but the interplay between the two can lead to complex patterns in the population growth of each. -LOOK AT GRAPH OF BOTH POPULATIONS IN LAB BOOK UNDER PREDATION

C difficile

A type of bacteria; pathogenic and may potentially harm the human host.

E coli

A type of bacteria; potentially beneficial because they produce vitamin K.

Oscillation around carrying capacity: how do you explain the oscillation of the population around the carrying capacity?

As the population gets older, they use more energy (you use more energy as you get older). When this population dies, this energy is lost, and energy goes into the next generation.

as we increased the level of a single environmental factor that served as a resource (which would be food, oxygen, etc), what happened to the relationship between the single resource and carrying capacity?

As we increased the resource, carrying capacity increased until another factor in carrying capacity limited it. So carrying capacity increased as the environmental factor increased but then the environmental factor continued to increase and carrying capacity stopped increasing.

At what degree of overlap was one population eliminated? Why might this eliminated population still persist when the level of overlap is below this level?

At 100%, population 2 was eliminated. It could still persist when it is below 100% overlap because there are still some resources available for competition.

stationary phase

Eventually, the food becomes scarce, room runs out, and pollution rises. These conditions tend to increase the death rate and lower the birth rate and population growth slows. Finally, in the stationary phase, the population size does not change, because the birth and death rates are equal. If the environment can meet the demands for food and space on a continuing basis, then a population may remain at the stationary phase for a long period of time.

How did the antibiotic affect the carrying capacities of the two populations?

It decreased E. coli and increased C. difficile -E. coli and C. difficile were competitors.

In the absence of antibiotics how is E. coli helping its host?

It keeps the C. difficile level down because it competes for the same resources.

Nontracheophyte plants

Nontracheophyte plants are the simplest examples of land plants. The land plants have major problems that aquatic species don't have to face: adequate water, means of water transport, and means of support. -most nontracheophytes must have moist habitats to thrive. They are small, and have some water conducting tissue, but lack tracheids within the plant. -mosses are the most common nontracheophytes.

From lab we were asked to consider a mosquito population whose growth is influenced by four factors: the availability of fruit, oxygen, discarded automobile tires, and methoprene. Which appeared to be the limiting factor and why?

Oxygen appeared to be the limiting factor because the carrying capacity changed the most or there was a significant change in carrying capacity when we varied the amount of oxygen. So oxygen is most likely to serve as a limiting factor.

carrying capacity (K)

The carrying capacity is the number of individuals in a population that an environment can support indefinitely. A population may level off in a stationary phase near the carrying capacity of its environment.

animals

The cells of animals are eukaryotic and lack cell walls. Animals are multicellular and heterotrophic; most are mobile; and they reproduce asexually or sexually. Animals also ingest their food and digest it internally.

seed-bearing vascular plants

The seed plants are the best adapted of all plants to terrestrial existence. -in addition to very well developed vascular system and other adaptations to handle water gathering and distribution, the development of seeds puts these plants at a distinct advantage when it comes to living on land: the sporophyte generation can, with seeds, suspend its development for long periods of time before resuming. -the two main groups of seed-bearing plants are gymnosperms and angiosperms.

log phase

Then, as time passes, the number of individuals increases, the birth rate still exceeds the death rate, and the population enters a period of rapid growth known as the log phase. In the log phase the organisms are reproducing, and there are many of them reproducing, thus accelerating growth.

As we increased the level of a single environmental factor that served as a more negative factor, what happened to the relationship between this single factor and carrying capacity?

This factor decreased carrying capacity linearly until another factor of carrying capacity influenced environmental factors. An example of such an environmental factor that would decrease carrying capacity would be loss of habitat, drought, etc.

In the lab we varied the degree of niche overlap to see which of two species is the more efficient competitor. Why was it important to first determine the carrying capacity for each population when their niches do not overlap?

This is important because by finding the carrying capacity at 0% overlap, we will know what the maximum carrying capacity is for each organism. This will allow us to know what carrying capacity to expect for the more efficient competitor when at 100% overlap. In this case, the carrying capacity for each organism at 0% overlap was 150. At 100% overlap, the carrying capacity for population 1 was 150, and the carrying capacity for population 2 was 0. Therefore, we know that population 1 was the more efficient competitor.

notochord

a flexible supportive rod of tissue running down the animal's back just ventral to the neural tube.

Polytrichum

a nontracheophyte, a moss

antibiotic

antibiotics are literally "anti-life" agents. Antibiotics kill certain types of bacteria, but are relatively harmless to human cells. So, a bacterial infection may be successfully treated with antibiotics while doing little harm to the human. Many antibiotics are taken orally and enter the digestive tract where they may kill some of the resident bacteria. Also, bacteria vary in their susceptibilities to antibiotics. In lab, the oral antibiotic in use was more harmful to E. coli than C. difficile.

lag phase

at first in logistic growth there is a lag phase during which the number of births is greater than the number of deaths, but the growth is slow because of the small number of individuals in the population (The organisms are reproducing, but there just aren't very many of them to do so, thus the slow start.)

Coeloms or not

bilateral animals have a tube within a tube body plan. The outer tube is equivalent to the skin of the organism; the inner tube is the digestive tract. Coeloms have to do with the spaces between the tubes. Three different types: acoelomates, pseudocolemonates, and coelomates.

competition: niche

central to understanding competition is the idea of a niche. The niche of an organism is defined by the range of resources it can use. -An example of a niche is paramecium caudatum. It is an aquatic single celled protist. One factor that determines its niche is the amount of oxygen dissolved in the water that surrounds it. -Competition occurs when niches overlap. When niches overlap, two or more organisms attempt to simultaneously use the same limited resource. Competitors are rarely equal; one is often more efficient than the other.

chlorophytes

chlorophytes are green algae. Like all plants these algae have chlorophylls a and b, and carotenoids. Some live on land, some in fresh water, and some in the sea. -Although chlorophytes are plants, they differ in on respect: the embryos of chlorophytes are unicellular, whereas the embryos of other members of the plant kingdom are multicellular. -The examples of chlorophytes from lab are Chlamydomonas and Spirogyra.

mollusks: visceral mass

contains vital organs, like those for digestion, excretion, circulation, and reproduction.

angiosperms

flowering plants -they are distinguished from gymnosperms in several ways: they produce flowers; gymnosperms do not. They have xylem vessels in addition to tracheids to convey water and minerals from the roots to the rest of the plant. Their seeds are enclosed in fruits, in contrast to gymnosperms.

growth rate of linear growth

growth rate is constant and independent of population size.

growth rate for logistic growth

growth rate is influenced by the difference between carrying capacity and population size.

growth rate for exponential growth

growth rate is proportional to population size.

Eumetazoans

have tissues. have either two different layers of tissue or three layers of tissue.

ferns

have very well developed vascular systems. -the fronds (leafy structures) you see on them are the sporophyte generation; the gametophyte is comparatively smaller and unobtrusive. On the underside of the fronds are reproductive structures called sori that produce the spores that become gametophyte. The sperm that are produced in the gametophyte must swim from the antheridia in which they're produced to the archegonia, which house the eggs. Because this must occur in a film of water on the surface of the gameophyte, ferns typically are restricted to relatively moist habitats.

acoelomates

in acolemoate animals the space between the tubes is completely filled with mesoderm cells.

formula for determining linear growth

in linear growth the population size (N) increases according to this equation: N=ct+N 0 c=rate of increase (change in population size per uint time) t=time (in generations) N =initial population size. 0

formula for determining exponential growth

in unrestricted exponential growth the population size (N) increases according to this equation: N=N e^rt 0 e=euler's number (2.718) r=intrinsic rate of increase t=time (in generations) N =initial population size 0

deuterostomes

it deuterostomes the anus develops first from the blastopore and the mouth develops secondly in another place. Deuterostomes means "mouth second".

how does the initial population size affect the carrying capacity?

it does not affect carrying capacity. carrying capacity is only affected by k.

exponential growth

occurs when the population size of each new generation is a multiple of the previous generation - for example, a population that doubles every generation. Under such conditions, the number of new individuals added continuously rises with population size. Exponential growth requires unlimited resources and a nearly vacant environment. This may happen after a disturbance (such as a fire, drought, or flood) wipes out most life in an area, or when a new area is occupied. However, no natural environment can sustain exponential growth for very long. -In exponential growth a fixed proportion of cells reproduce. -with exponential growth the rate of increase and slope are not constant, but are constantly changing. The growth rate is proportional to the population size, so as the population grows, the growth rate increases.

protostome variations

protostomes fall into two large classes. The ancestors of one class underwent molting, the other ancestors of the other class did not molt. Molting occurs when an organism outgrows its stiff, outer skeleton and must shed it in order to grow larger.

How does r affect carrying capacity?

r does not affect carrying capacity.

Gymnosperms

seed-bearing plants. -of the gymnosperms, the most well known are the coniferophyta, "pine" trees, complete with pine cones. Other divisions to be aware of are cycadophyta (palm-like leaves), and Ginkgophyta (with fan-shaped leaves). -the cones of conifers are as close to flowers as these gymnosperms come -they also have less emphasis on the gametophyte generation -the examples of gymnosperm used in lab were cycad, ginkgo, and a pine tree.

Whisk ferns

simple vascular plants. Whisk ferns lack leaves and don't really have roots. -they have a primitive vascular system composed of xylem and phloem that is restricted to the stem of the plant.

linear growth

simplest of the three patterns. Example includes corn seed which consists of an embryo and a food supply. -in linear growth a fixed number of cells reproduce in each generation. -in linear growth the rate of increase (and slope) are constant.

sponge reproduction

sponges reproduce asexually by budding, or a broken-off piece of a sponge may form a whole new Poriferan of its own. Sponges may also reproduce sexually: usually some of the amoeboid cells within one sponge develop into sperm and eggs, which unite to form zygotes that develop into mobile larvae.

nematocysts

the "sting" of a jellyfish; the structure that cnidarians use to immobilize their prey

which population had the competitive advantage before the addition of antibiotic?

the E. coli

three-layered animals: bilateral

the bilateral animals may be divided into two large groups according to developmental pattern: protostomes and deuterostomes. -During early development, bilateral embryos produce three distinct layers of cells: ectoderm, endoderm, mesoderm

blastopore

the endoderm is connected to the blastopore which is a hole. In protostomes the blastopore become the mouth of the organism and the anus develops later.

Ascaris

the example of a roundworm given in lab. it is a molting pseudocolomate protostome. It is parasitic on humans.

gametophyte and sporophyte generations of nontraacheophytes

the gametophyte generation of a moss is somewhat more prominent than the sporophyte generation. -the sporophyte, which consists of a stalk topped with a capsule full of spores, grows from the gametophyte, which is the leafy part that is so characteristic of moss.

how does the intrinsic rate of increase (r) affect the rate of growth? (especially how does it affect the time required to reach carrying capacity?)

the higher the r, the less amount of time required to reach capacity.

gastrodermis

the inner layer of two-layered animals (cnidarians)

Endoderm

the innermost layer of bilateral animals. It contributes in major ways to the digestive tract. Forms the primitive gut, which is the precursor to the digestive tract. This precursor is connected to the outside of the embryo via a hole called the blastopore.

how does the initial population size affect the time required to reach carrying capacity?

the larger the population size, the faster carrying capacity is reached

Mollusks: mantle

the mantle is a heavy fold of tissue that may contain glands that secrete a protective shell

mesoderm

the middle layer of bilateral animals. Becomes muscles.

Protostome

the mouth comes before the anus. That is what protostome means: proto = first and stome = mouth.

Ectoderm

the outer layer of bilateral animals. it develops into the outer layer of the skin.

two-layered animals: cnidarians

the simplest eumetazoans have two layers of tissue. The outer layer corresponds to the skin and the inner layer is part of the digestive system. They have radial body symmetry. They have their body arranged around a central axis, like the spokes of a wagon wheel. -most cnidarians are salt-water creatures. The outer layer has some cells specialized for both protection and sensation, while others are contractile in nature. The inner layer, called the gastrodermis, has cells specialized for contraction and digestion. The gastrodermis lines a digestive cavity that has but one opening that serves as both the mouth and anus. -Cnidarians are heterotrophs. They prey on other organisms by catching them in their tentacles, immobilizing them with structures called nematocysts, and then moving the meal into the digestive cavity. -cnidarians include hydras, jellyfish, and corals.

Pseudocoelomates

the space is not filled with cells; the mesoderm supply lines the inner surface of the body covering. In contrast, mesodermal cells do not cover the digestive tube itself.

Coelomates

the space is not filled; the mesoderm also lines the inner surface of the body covering, but in this case mesodermal cells cover the digestive system.

Pterophytes

tracheophyte plants -Whisk ferns -ferns

tracheophyte plants

tracheophyte plants are much better adapted for terrestrial (land) habitats than are nonvascular plants. -the most important adaptation is that they have transport systems to carry water from the soil to all parts of the plants, and to conduct nutrients made by some parts of the plant to other parts of the plant. The culmination of this is the existence of trees that grow as tall as 100 meters from the ground.

mollusks: foot

used for getting from place to place

Plants: zygote

when a sperm fertilizes an egg, a single-celled zygote is formed. The sperm donates one set of chromosomes to the zygote and the egg donates another, corresponding set as well. The zygote then contains two sets of chromosomes; or, put it another way, the chromosomes are in pairs. By analogy, this would be like getting shoes for your birthday: dad gives you a right shoe and mom gives the corresponding left shoe: you now have a pair of shoes.

plants: diploid

when there are two chromosomes of each type in a cell, the cell is diploid.