UNIT 3 Flashcards
Most viruses are composed of what?
of a nucleic acid and a few proteins
Viroids are made up of what ? They are the … infective agents?
they are made up only of a nucleic acid (genetic material). /simplest
Viruses are …. and because of that they do not metabolize energy?
acellular (noncellular)
What can viruses not produce?(4)
ATP or conduct fermentation, cell respiration, or photosynthesis
Where can viruses reproduce?
only in systems that do perform these functions: living cells
Viruses are considered…?
Not alive
What does obligate intracellular parasites mean?
They are obligated to reproduce inside a cell.
Viruses are obligate intracellular parasites that ….and …. only within living cells of a specific hosts?
that develop and reproduce
How does viruses reproduce? What happens to the host cell?
Viruses reproduce using the host’s synthetic machinery and usually destroy the host cell in the process.
what is synthetic machinery?
Its everything in the cell (ribosome, DNA, like a factory which they intrude).
What happens when the host cell release the progeny of replicated viruses?
It infect new hosts. (cell)
Outside the cell, the individual viral particles are called?
virions
What is the virion genetic material?
its either DNA or RNA
What generally surrounds virion?
a capsid (or protein coat).
The characteristic shape of virion are determined by what?
by the protein coat
Are viruses affected by antibiotics? Why?
No ,because they lack the cell wall structure and ribosomal biochemistry of bacteria.
Viruses are described according to four different criteria. What are they?
1-Whether the genome is DNA or RNA
2-Whether the nucleic acid is single-stranded or double-stranded
3-Whether the shape of the virion is a simple or complex crystal
4-Whether or not the virion is surrounded by a membrane
Viruses that infect bacteria are called?
Bacteriophage (or phage)
How does bacteriophage recognize their host?
By means of specific binding between proteins in the capsid and receptor proteins on the host’s cell.
The virion are equipped with ….. that inject the phage nucleic acid into the host cell?
With tail assemblies
The virus may do what when entered in a host?
may reproduce immediately and kill the host, or postpone reproduction by integrating its nucleic acid into the host’s genome.
What are the two types of reproductive cycles?
(1) the lytic cycle and (2) the lysogenic cycle
What happens in the lytic cycle?
The infected bacterium lyses (breaks down), releasing the progeny phage
What are called the phage that only have lytic cycles ?
virulent viruses
What happens in the lysogenic cycle?
the host cell does not lyse (break down), but harbors the viral nucleic acid for many generations.
What are called the phage/virus that only have lysogenic cycles ?
temperate viruses
What are the three mains domains for all living organisms ?
Bacteria, Archaea, and Eukarya
Is it true that the two prokaryotic domains of Archaea and Bacteria differ from each other more radically than the Archaea from the Eukarya?
true
What are the most successful organisms on Earth in terms of number of individuals ?
Prokaryotes
Where can prokaryotes be found? What type of habitat on earth?
They are found in every type of habitat on Earth.
What are the three common body shapes of prokaryotes?
- Sphere or coccus (plural cocci)
- Rod or bacillus (plural bacilli)
- Helical or spirillus (plural spirilli)
What do Prokaryotes lack?
Nuclei, and membrane- enclosed organelles
How does the prokaryotes chromosome look like?
one circular chromosome
Is it true that many prokaryotes are motile(mobile)?
true
How do prokaryotes move(most of them)?
Most move with a flagellum (pl. flagella). Prokaryotic flagella rotate.
Do Prokaryotic cell walls differ from those of eukaryotes (plants, fungi, and algal protists)?
Yes
How do Prokaryotic cell walls differ from those of eukaryotes (plants, fungi, and algal protists)?
– Bacterial cell walls generally contain peptidoglycan (a polymer of amino sugars).
– Archaea, however, do not have peptidoglycan.
How can you find the differences in peptidoglycan content? What is the name of the substance reacted upon? What are the results?
From different reactions to the Gram stain/
• Gram (+) have lots of peptidoglycan and appear purple.
•Gram (–) have very little peptidoglycan and appear red.
How do prokaryotes reproduce asexually ?
by binary fission
How do prokaryotes reproduce sexually ?
by exchanging genetic information, called conjugation.
What type of cell have only all 3 metabolic pathways and what are they?
prokaryotes/obligate aerobes, obligate anaerobes, facultative anaerobes
What are the 4 categories of nutrition for prokaryotes? (They are the only one to have it)
photoautotrophs, photoheterotrophs, chemoautotrophs, and chemoheterotrophs.
Some prokaryotes play key roles in global….cycles and what are there names ?
nitrogen and sulfur/Nitrogen fixers & denitrifiers do so in the nitrogen cycle.
What generated the oxygen gas that permitted the evolution of aerobic respiration and the appearance of present-day eukaryotes ?
Photosynthesis by cyanobacteria
Is it true that only a big majority of known prokaryotes are human pathogens (i.e., disease- causing organisms)?
False , small/minority
Many prokaryotes are ……—they metabolize organic compounds in dead organisms and other organic materials.
decomposers
There are far more known (archaea/bacteria ) than(bacteria/archaea)
Bacteria,archaea
Taxonomy of bacteria has been based on characteristics, what are they?(6)
shape, color, motility, nutrition, antibiotic sensitivity, and gram-stain reaction
How many clades of bacteria have been proposed under a currently accepted classification scheme?
Over 12
What is chlamydia bacteria?
They are extremely small, and live only as parasites within cells of other organisms.
What is cyanobacteria?(what can they do?)
unlike other bacteria, they can
photosynthesize (similar to plants). Many species can also fix nitrogen. Ex., Anabaena
What is firmicute bacteria? (Produce)
They are very diverse. Some produce endospores (resting structures resistant to harsh conditions). Ex., Bacillus, Staphylococcus
What is actinomycetes bacteria? ( produce)
They produce important
antibiotics. Grow as branching filaments. Ex., Mycobacterium tuberculosis
What is mycoplasma bacteria?
the tiniest of all living organisms, lack conventional cell walls, and have very small genomes.
What is proteobacteria?
It’s the largest group of bacteria (ex., E.coli). Includes some nitrogen-fixers, such as Rhizobium
Archaea are famous for …. such as ..4..?
Archaea are famous for living in extreme environments:
high salinity, high temperatures, high or low pH, and low oxygen.
Archaea are divided into two main clades what?
Euryarcheota and Crenarcheota
Most know crenarcheota are both?
thermophilic and acidophilic
Some euryarcheota are ….(produce methane gas, CH4)
are methanogens
Some euryarcheota live in… (2)?
- Some live in the guts of herbivorous animals.
* Some in high-temperature environments on the ocean floor.
Some Euryarcheota are extreme ….? These salt lovers lend a pinkish color to salty environments; some grow in extremely alkaline environments.
halophiles
How did the modern eukaryotic cell arise from?
An Ancestral prokaryote
What would be the probable steps for the formation of modern eukaryotic cell? (4)
▪loss of the cell wall,
▪inward folding of the plasma membrane,
▪an infolded plasma membrane attached to the chromosome may have led to the formation of a nuclear envelope,
▪a primitive cytoskeleton evolved.
We define protists as all eukaryotes that are not….3 ?
plants, fungi, nor animals
Protist are monophyletic (one ancestor) or polyphyletic(many ancestors) ?
polyphyletic (i.e., many ancestors).
Most protist are …. and others live within other organism?
Aquatic
The great majority of protist are 2…. but many are multicellular, and a few are enormous ?
are unicellular and microscopic
_ is an outdated term applied to photosynthetic protists.
Algae
_ is an outdated term applied to protists once classified as animals.
Protozoa
_ is an outdated term applied to fungi-like protists.
Slime moulds
What are phylum pyrrophyta?
They are unicellular and photosynthetic.
- Reddish brown pigments.
- Major contributors to world photosynthesis. •Contribute to growth of coral reef.
- Cause “red tides”.
What are apicomplexa??
They are unicellular and heterotrophic.
• All are parasitic.
• The genus Plasmodium causes the disease malaria.
What are ciliophora (ciliates)??
They are unicellular and heterotrophic.
• Have numerous cilia.
• Have two types of nuclei.
What are bacillariophyta (diatom)??
They are unicellular and photosynthetic.
- Yellow or brown carotenoid pigments.
- Contribute to world photosynthesis.
- Have “glassy” cell walls made of silica.
What are Phaeophyta (Brown algae)??
They are mostly multicellular and photosynthetic.
• Brown carotenoid pigments.
• They include the largest of all protists (i.e., Giant Pacific kelp).
• Show tissue differentiation.
What are rhodophyta (red algae) ??
They are multicellular and photosynthetic.
• Red pigments.
• Their storage product is floridean starch.
• Their gametes are not flagellated.
What are chlorophyta (Green algae)??
They are mostly multicellular and photosynthetic.
• Green chlorophylls a & b, like plants.
• Their storage product is starch, like plants.
• Are sister to the plants (Plant kingdom).
What are choanoflagellida??
They are unicellular and heterotrophic.
•They have a flagellum.
•Body type similar to a characteristic type of sponge cell called the choanocyte (“collared” cell).
•Are sister to the Animal kingdom.
What is fungi?
They are heterotrophic eukaryotes with absorptive nutrition.
Fungi degrade….in the biosphere, and are …. of almost all vascular plants ?
dead organic matter//nutritional partners
Some fungi can be .. of plants and animals?
can be serious pathogens or parasites
What are the 3 groups of fungi and their meanings?
decomposers: absorb nutrients from dead organic matter,
parasites: absorb nutrients from living hosts,
or
mutualists: both partners benefit.
Some fungi ( yeast ) are ….? (Cellular)
Unicellular
Most fungi are ….? (Cellular)
Multicellular
Multicellular fungi are composed of ? (3)
Hyphae
Mycelium
Hyphae cell walls
What is a hyphae?
each of the branching filaments that make up the mycelium of a fungus. (tubular filaments)
What is a mycelium?
An underground mass of hyphae (the main body of the fungus)
An hyphae cell wall contains?
Chitin
What are the steps of asexual reproduction in fungi?
- Cell division by unicellular fungi: fission (also called budding).
- Production of spores.
- Breakage of the mycelium.
When and how do fungi sexually reproduce?
• Fungi reproduce sexually when hyphae of different mating types meet and fuse (see example of Zygomycota)
What are the 4 fungi phyla kingdom ?
▪Chytridiomycota ▪Zygomycota ▪Ascomycota; and ▪Basidiomycota.
These phyla (4 kingdoms fungi) differ in their ...?(2)
in their reproductive structures, and mechanisms of spore formation.
The Chytridomycota have …and ressemble..?
flagellated spores and gametes//probably resemble the ancestral fungi
The Zygomycota reproduce sexually by ….
fusion of hyphae. This makes zygosporangia that contain zygospores.
The Ascomycota have a sexual reproductive structure called ?
an ascus that contains ascospores
The Basidiomycota have a sexual reproductive structure called ?
a basidium that contains basidiospores.
What is Mycorrhizae ? (Association)
mutualistic associations of fungi with plant roots, enhance the ability of the roots to absorb water and nutrients. The fungus gets sugars and proteins from the plant.
What is Lichens ? (Association)
mutualistic associations of a fungus with a cyanobacterium (or a green alga), are found in some very inhospitable environments (very cold, very dry, etc)
Plants arose from ..? (Ancestor)
A common green algal (chlorophyta) ancestor
What are the traits the plants share with green algae? (3)
Chlorophyll a and b
Starch as a storage product
Cellulose in cell walls
Surviving phyla of plants are grouped into 2 main categories what are they called?
Non-tracheophytes and tracheophytes
Non-tracheophytes(non vascular plants ) lack what?
A vascular system
tracheophytes (vascular plants) are characterized by what?
A vascular system containing tracheids
What can help the Adaptation of plants to the land? (5)
A waxy cuticle
Gametangia: organs enclosing gametes
Embryos in a protective structure
Pigments that protect against UV radiation
Mycorrhizae: mutualistic relationship with fungi
The Non-tracheophytes include ?(3)
Liverworts,hornworts and Mosses
Do Mosses have a rudimentary (basic form ,undeveloped) system?
Yes
In dominant gametophyte (non-tracheophytes), what happens to the sporophyte generation in relation to the gametophyte generation?
The sporophyte generation is smaller than the gametophyte generation and depends on the gametophyte for water and nutrition
How do gametophyte look like ? (Liverworts/ hepatophyta)
Are flattened and leafless
How do sporophytes look like and where do they grow? (Liverworts/ hepatophyta)
Are very short (a few mm) and grow on the gametophyte
How do gametophyte look like ? (Hornworts/Anthocerophyta )
Are flattened plates of cells (very similar to those of liverworts
How do sporophytes look like and how do they grow? (Hornworts/ Anthocerophyta)
They grow as green , elongated, horn-like structure upward from the gametophyte
How do gametophyte look like ? (Mosses/bryophyta)
Green and leafy
How do sporophytes look like? (Mosses/bryophyta)
Long, non-photosynthetic stalk , at the top of which is a capsule
Some moss species are … to the vascular plants?
Probably sisters
In tracheophytes , there is an appearance of…?
Appearance of tracheids
In tracheophytes , how come sporophyte is the dominant sporophyte ?
The sporophyte generation is larger and nutritionally independent of the gametophyte
tracheophytes form 2 major groups what?
Non-seed and seed plants
In non-seed tracheophytes Mosses(lycophyta) , the gametophyte is… and the fertilization results in …?
Is small and grows right below the ground level. // sporophyte
In non-seed tracheophytes Mosses(lycophyta) , sporophyte are ..(look)?
Evergreen, bearing needle-like leaves
In non-seed tracheophytes , club Mosses(lycophyta) have …?
Sporangia arranged in clusters called strobili
In non-seed tracheophytes , Ferns(pteridophyta)what is their “reproduction cycle”? (Gametophyte, zygote)
Gametophyte produce both sperm and eggs
Zygote develops into a sporophyte that quickly becomes independent
In non-seed tracheophytes ,Ferns(pteridophyta), sporangia are found where?
On the undersurfaces of fronds , clustered in groups called Sori
What is homospory?
Is the production of one type of spore that gives rise to one kind of gametophyte that makes both eggs and
sperm
What is Hererospory?
It’s the production of the two types of spores (female megaspores and male microspores) that give rise to female and male gametophyte
Is it true that non-tracheophytes are all heterosporous?
False , they are all homosporous
Is it true that all seeded tracheophytes are heterosporous?
True
Surviving seed plants fall into two groups what are they?
Gymnosperms: naked-seed plants
Angiosperms: flowering plants
Is it true that seed plants are all heterosporous, and have greatly reduced gametophytes.
True
What is gymnosperm? And what is happening for the seed and ovule?
“naked-seeded”—the ovules and seeds are not protected by ovary or fruit tissue
What is the living phyla discussed ?
Coniferophyta (cone-bearing plants)
seed cone make what gametophyte? Gender
make female spores that produce the female gametophyte.
Pollen cone make what gametophyte? Gender
make male spores that produce the male gametophyte (pollen)
Conifers have a life cycle in which naked seeds are produced on the scales of what ? Gender
of female cones.
How can seed cones be fertilized?
Wind carries pollen grains from pollen cones to seed cones.
How does the conifers reproduce? (Fertilization story)
Pollen sticks onto seed cone, pollen tube develops and sperm descends, fertilizes the egg, embryo develops within the female gametophyte, a seed develops around the embryo, mature cone releases winged seed that is dispersed by wind.
What is Angiosperm?
“ enclosed seed ” —the ovules and seeds are enclosed in a carpel.
What phylum is the angiosperm composed of ?
one phylum: Angiospermae/Anthophyta (flowering plants)
How can angiosperms be distinguished from others?
▪ Flowers ▪Ovules and seeds enclosed in a carpel ▪Double fertilization ▪Triploid (3n) endosperm ▪Fruits
What does the stamen do?
It bears spores that develop into the male gametophyte (pollen)
▪stamen: anther and filament
What does the pistil do?
It bears spores that develop into the
female gametophyte.
▪pistil: stigma, style, and ovary (one or more carpels).
Flower physicals made up of ?(4) that differ from flower to flower
pistils, stamens, petals, and sepals
How is the pollen dispersed?
Wind, but mostly animals (pollinators)
Pollen grain have 2 sperms, what are they?
❑one sperm combines with egg to give the embryonic sporophyte.
❑the other sperm combines with two haploid nuclei of female gametophyte to form a triploid nucleus—becomes the endosperm.
What nourishes the sporophyte in flowers?
Endosperm
The embryo has how many cotylédons?
1 or 2
What is catyledons?
embryonic seed leaves
catyledons absorb and digest what?
the endosperm
Ovary developes into _ that carry seeds?
fruits
Fruit _ seed and _ in dispersal
protects//aids
There are two major classes of flowering plants what ?
monocots and (eu)dicots.
What is the common flagellated protist ancestor of all members of the kingdom Animalia?
Choanoflagellida
What has radial or bilateral symmetry?
Most animal
Radially symmetrical animals move slow or fast?
Slow
Those with bilateral symmetry have more ….?
rapid movements and sensory organs
Is it true that the porifera (sponges) have no body symmetry, and have several cell types.
True
Sponges feed with _, which are feeding cells that filter out small organisms and nutrients.
Choanocytes
Is it true that the Cnidarians are radially symmetrical.
True
The cnidarian gut is a blind-sac called _ . What it’s functions?(3)
the gastrovascular cavity//in digestion, circulation, gas exchange
Exemples of cnidarians organisms?
jellyfish, sea anemone, coral, and hydrozoans
What do Platyhelminthes (Flatworms)have ?(organidm components,move)
They have only one gut entrance/exit, and move via cilia.
Many flatworms (Platyhelminthes) are ….?
Internal parasites
How does Platyhelminthes (flatworms) feed? (Absorbing of nutrients)
They absorb digested food from the digestive tract of the host.
Exemples of Platyhelminthes (flatworms)?
planaria, tapeworms, flukes
What do Nematoda (roundworms )have ?(organism components)
They have a thick, unsegmented, white or transparent, multilayered cuticle.
The guts of Nematoda (roundworms )have ?(2)
A mouth and an anus
Almost all of Nematoda (roundworms ) are ?
Parasite
Exemples of Nematoda (roundworms ) ?
Ascaris, Trichinella, Echinococcus, vinegar eel.
What are annelids (segmented worms)? And where do they live?
They are a diverse group of segmented worms that live in marine, freshwater, and terrestrial environments.
Most of annelids (segmented worms) have a _ body wall that serves for _ ;restricted to aquatic or moist habitats.
very thin, permeable//gas exchange
Exemples of annelids (segmented worms)?
earthworm, leech
What are the body components (3) of Mollusca (soft-bodied animals) ?
foot, visceral mass, and mantle
What is contained in the foot body plan component of Mollusca (soft-bodied animals) ?
large, muscular structure, for locomotion
What is contained in the visceral mass body plan component of Mollusca (soft-bodied animals) ?
all internal organs (ex., heart, digestive, excretory, reproductive, etc.).
What is the mantle body plan component of Mollusca (soft-bodied animals) ?
fold of tissue that covers organs in the visceral mass. In some species, the mantle secretes a calcareous shell.
Exemples of Mollusca (soft-bodied animals) ?
snail, slug, clam, oyster, mussel, squid, octopus.
Arthropods are the _ animals on Earth. About 1,000,000 species have been described.
Dominant
In the Arthropods (jointed-limb animals) , how are their skeletons and what does it provide and prevent?
Rigid exoskeleton (chitin & protein) provides support for walking on land, prevents drying, and provides some protection against predators.
Most Arthropods (jointed-limb animals) have 3 body regions ,what are they?
head, thorax, abdomen.
Exemples of Arthropods (jointed-limb animals)?
lobster, crab, shrimp, cockroach, beetle, butterfly, spider, scorpion, louse, tick, mite, centipede, millipede
What do echinoderms (spiny-skinned animals) have? (Body composition)
They have a unique water vascular system, and a calcified internal skeleton.
echinoderms (spiny-skinned animals) larvae have _ symmetry,but as they develop into adults, it changes to _ symmetry.
Bilateral//penta-radial
Exemples of echinoderms (spiny-skinned animals)?
sea star, sea urchin, sand dollar, sea cucumber
Members of chordates [Chordata (Animals with a notochord)] are united by some time in their life cycle, what ? (4)
Dorsal,hallow nerve cord
Notochord
Pharyngeal Gill slits
Post-anal tail
Phylum chordata has 3 sub-phyla, one is only important, what is it called?
Vertebrata
Members of Vertebrata [Chordata (Animals with a notochord)] evolved _ ( replacing the notochord during early development? This which allowed for rapid movement.
Internal skeletons around a jointed , dorsal vertebral column
Vertebrae’s have moved /radiated where?
In marine, freshwater, and terrestrial habitats
There are 7 classes of vertebraes, what are they called?
Agnatha, Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, Mammalia
What are Agnatha (Jawless Fish) ?
They are jawless fish with circular mouths, and a cartilaginous skeleton—hagfish, lamprey.
Most species of Agnatha (Jawless Fish) are ?
Most species are parasitic feeding on blood
What are Chondrichthyes (Cartilaginous Fish) ?
They are finned fishes with skeletons of cartilage (rather than bone)—ray, skate, shark, and chimaera.
What are Osteichthyes (Bony Fish) ?
They are finned fishes with calcified bones—tuna, salmon, perch, trout, sea-horse,eel
What is ethology?
The study of animal behavior from an evolutionary perspective.
In ethology, most behaviours results from what?
from complex interactions between inherited mechanisms and experience.
What are proximate mechanisms?
neuronal, hormonal, anatomical mechanisms.
What are ultimate cause?
selection pressures that shaped evolution of the behavior.
Is it true that Much of animal behavior is unlearned and called stereotypic (i.e., always the same) or innate (ex., web spinning in spiders)?
True
Stereotypic behaviour is often _ (ex., spider species can be identified by the pattern of their webs)
Species-specific
Genes do not encode behavior ; but _ (such as enzymes) can affect behavior
Gene product
How can gene products (such as enzymes) affect behaviour?
by starting a series of gene- environment interactions that underlie development of proximate mechanisms.
Some types of learning take place at specific times in an animal’s life, called ….?
Critical period
What is imprinting?
the animal learns a set of stimuli during a limited critical period (ex., recognition of parents, food, suitable sexual partner, etc.).
Some behaviour results from both _and _? With an exemple?
Inheritance and learning
Male songbirds have species-specific songs used in territorial displays and courtship.
Ex., White-crowned sparrows must hear the song when they are nestlings (i.e., critical period), even though they don’t sing it for a whole year. Females don’t sing because of difference in hormones.
Animals must make many decisions such as?
where to live, when to leave, what to eat, and which other animals to associate with.
These decisions must be made in an environment that may be quite variable, and will ultimately influence what ?
Fitness
Is habitat selection one of the most important decisions?
Yes
The habitat selection must provide what? (5)
food, shelter, mates, nest sites, escape routes, etc.
Is it true that behavioural ecologists try to determine what information is used select a habitat, and how it relates to their fitness?
True
What can be used to analyze the behaviors of animals ?
cost-benefit approach
What are the 3 components of cost in the cost-benefits approach?
- Energetic cost –
- Risk cost –
- Opportunity cost –
What is energetic cost?
difference in energy expended if resting vs energy expended in performing the behavior.
What is risk cost?
increased chance of being injured or killed as a result of the behavior.
What is opportunity cost?
benefits the animal gives up by not performing other behaviors during the same time
What is a population?
a group of organisms of a single species that interbreed and live in the same place at the same time
What is exponential growth & the formula linked to it?
is continuous population growth in an environment where resources are unlimited; it is density-independent growth.
dN/dt = rN
where:
dN/dt = change in population size; N = population size;
r =per capita growth rate (assuming no immigration, nor emigration).
[ r=(Births - Deaths)/N , or, r=(birth rate - death rate), or, r=(N2 - N1)/N1 ]
When birthrates are as high as possible and death rates are as low as possible, r reaches a maximum value called the ….?
intrinsic rate of increase, r max
Is it true that Species that breed at a young age and produce many offspring have a high r max (ex: fruit flies and bamboo) ?
True
Is it true that species that take a long time to mature and have few offspring per year have a low rmax (ex: Giant pandas and palm trees)?
True
Some populations may grow at rates close to their r , but, only _ It is common in rebounding populations and founding populations.
Very short period of time
Real-world populations (as opposed to lab- reared) cannot _ ?
Maintain exponential growth for long
When the population gets large enough, resources get used up, _?
slowing the growth rate.
What causes birth rates to decrease, and death rates to increase? What does this growth called?
Environmental limits //density-dependent.
Eventually, in population ecology,the growth rate will plateau, or level off, making an _?
S-shaped curve.
In ecology,The population size at which it levels off (which represents the maximum number of individuals a particular environment can support) is called the _?
carrying capacity (K).
The growth called logistic growth, what is the formula?
dN/dt = r [(K-N)/K] N
In logistic growth, birth rates and death rates are influenced by _?
density-dependent factors:
What are exemples of density-dependant factors?
–As population density increases, food supplies may be depleted, reducing amount of food available to individuals.
–Predators may be attracted to high densities of prey, increasing death rate.
–Diseases can spread more easily.
Populations are also influenced by density-independent factors, that may _? Give exemple?
kill a large number of individuals in a population regardless of the population’s density.//Ex.: weather-related phenomena (intense storms, cold periods, etc.) and disasters.
What are the 5 factors that have trong influence on the variation of population density among species (Some species tend to be more common than others.)?
1) Life span & reproductive rates
2) Resource abundance
3) Size of individuals
4) Length of time a species has lived in an area
5) Social organization
Explain each of the 5 factors that have trong influence on the variation of population density among species?
1) In general, more stable population numbers are seen in species with long- lived individuals and low reproductive rates.
2) Species that use abundant resources generally reach higher population densities than those using scarce resources.
3) Species with small body size generally reach higher population densities.
4) Species that are introduced to a new region where their normal pathogens & predators are absent can reach very high population densities (i.e., invasive species).
5) Complex social organization can lead to high population densities.
What is r-strategists?
life history strategies that allow for high intrinsic rate of increase.
What is K-strategists?
Life history strategies allow them to persist at or near the carrying capacity.
What does an ecological community consist of ?
It consists of all the species that live & interact in a given area.
Organisms in a community can be divided into _ based on their source of energy.
trophic levels
Seed plants produce 2 types of spores: what are they? (Gender) As well as how do the gametophytes meet?
Sperm from the male gametophyte (pollen) fertilizes the egg from the female gametophyte resulting in a diploid zygote.
How does seed plant fertilize?
Diploid zygote divides to produce an embryonic sporophyte.
• Growth is then suspended, the embryo enters a dormant stage, and a multicellular seed develops around it.
The seed is a _ stage?
well-protected resting
Seed coats protects from_ , as well as Predators?
drying out
What does an ecological community consists of ?
An ecological community consists of all the species that live & interact in a given area.
How can organisms in a community be divided has? (Based on their source of energy)
trophic levels
What the different trophic levels and what are they?
1) Primary producers ; are autotrophs (photosynthesizers) that get their energy directly from sunlight.
2) Primary consumers are herbivores that eat plants and other autotrophs;
3) Secondary consumers are carnivores that eat herbivores;
4) Tertiary consumers are carnivores that eat secondary consumers, and so on.
Except the primary producers that are autotroph (photosynthesizers) , all other trophic levels have _?
heterotrophs that consume (directly or indirectly) the energy-rich molecules made by the primary producers.
Organisms that get their food from more than one trophic level are called?
Omnivores
What do Detritivores (or decomposers) eat?
They eat dead bodies and waste products, transforming detritus into free mineral nutrients that can be recycled by producers.
What is the food chain(the sequence)?
A sequence in which a plant is eaten by an herbivore, which is eaten by a primary carnivore, etc.
Food chains are interconnected to make what?
More complex food webs
What are the 5 species interactions categories?
(1) If both participants benefit from an interaction, the interaction is a mutualism (+/+ interaction).
(2) If one participant benefits but the other is unaffected, the interaction is a commensalism (+/0 interaction).
(3) If one participant is harmed but the other is unaffected, the interaction is an amensalism (–/0 interaction).
(4) One organism may benefit itself while harming another organism; these interactions are called predator–prey and parasite–host interactions (+/– interactions).
(5) If two organisms use the same resources and those resources are insufficient for their combined needs, they are in competition (– /– interaction).
What are amphibians?
Beings that have juvenile stages that live in water and have gills to breath, whereas the adults breath through lungs and skin, and live on land—frog, toad, caecilian, salamander, mudpuppy.
What are reptilians?
Beings that have dry, water-proof scaly skin and shelled eggs, as well as internal fertilization. They are the first truly terrestrial vertebrates — snake, turtle, lizard, and crocodilians.
What are Aves?
Beings that are characterized by feathers, a beak with no teeth, hard-shelled eggs, and a lightweight but strong skeleton. Forelimbs are modified as wings, and most can fly—owl, cardinal, duck, eagle, penguin, ostrich.
What are the mammalia?
Beings that are characterized by the presence of sweat glands, mammary glands, hair, and internal fertilization with mostly live birth—rat, bat, cat, dog, reindeer,dolphins,whale, monkeys,humans
