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69 Cards in this Set
- Front
- Back
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Species
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"Species are distinct types of organisms and represent evolutionarily independent groups"
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Classification of Species
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binomial nomenclature
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Definition of a species:
Biological Species Concept |
Species are groups of interbreeding natural populations that are reproductively isolated from other such groups.
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Definition of a species:
Morphological Species Concept |
Based on the appearance of the body alone---size, shape, or other morphological features. The logic is that distinguishing features are most likely to arise if populations are independent and isolated
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Definition of a species:
Phylogenetic Species Concept |
based on reconstructing evolutionary history of populations. Phylogenetic trees are used to represent genealogical relationships
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Speciation:
Allopatric speciation |
A physical barrier arises and separates populations or subpopulations of a species, gene flow stops, and favors divergence that ends in speciation
e.g. Hawaiian Honeycreepers |
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Speciation:
Sympatric Speciation |
a speciation event within the home range of an existing species, in the absence of a physical barrier
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Speciation:
Parapatric Speciation |
speciation in which the new species forms from a population contiguous with the ancestral species' geographic range. Hybrid zones exist where the species ranges meet.
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Speciation:
Polyploidy |
a change in the number of chromosomes, offspring inherit three or more of each type of chromosome from the parents. This occurs when:
chromosomes separate improperly during meiosis or mitosis or germ cells (pre-egg or sperm) replicates its DNA but fails to divide |
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Reproductive Isolating Mechanisms:
Prezygotic isolation |
Ecological
Temporal Behavioral Mechanical Gametic |
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Reproductive Isolating Mechanisms:
Postzygotic Isolation |
Hybrid inviability causes an inviable offspring to be produced through hybridization.
Hybrid sterility. |
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Virus
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obligate, intracellular parasites
outside of host cell, they simply exist. Viruses satisfy many properties of life: highly organized reproduction respond to environments they evolve most viruses do not cause disease. Some actually introduce useful genes. |
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Viral Reproduction
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1) Penetration
2) Replication 3) Transcription 4) Protein synthesis 5) Viral assembly 6) Release |
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Viral Reproduction:
Penetration |
Virus attaches to host cell
this attachment depends on the viral protein and the receptor used on the host cell's membrane (Attachment site may be on all host cells or just a special set) Major Means include: 1) cutting a hole in the cell 2) inducing the cell to engulf it 3) fusing with the cell membrane - by stealing a piece of the host membrane as they leave the cell they easily bind with the new cell |
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Viral Reproduction:
Replication |
The cell replicates the virus DNA
a) autonomous replication- the genes are separate from the DNA of the host cell b) integrated replication- the genes become replicated into the host's DNA and are replicated along with the host. |
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Viral Reproduction:
Transcription |
Viral genetic material is used as a blueprint to make mesenger RNA.
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Viral Reproduction:
Protein Synthesis |
The cell synthesizes proteins from virus' genes:
1) direct the cell to make an enzyme that destroys the cell's DNA 2) other virus' depend on quick replication, transcription, and translation 3) in most cases, a host cell is forced to make virus proteins instead of its own |
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Viral Reproduction:
Viral Assembly |
The viral genetic material and enzymes are surrounded by their protein coat (ready to infect new cells)
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Viral Reproduction:
Release |
After new viruses are produced, in some viruses a viral enzyme causes the host cell to break open in a process called lysis.
Other viruses can exit the cell without destroying it. |
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Examples of Human Viruses
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Herpes
Hepatitis Rabies Ebola Influenza HIV |
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Other infectious agents
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Viroids: Infectious particles that lack protein coat
Prions: dangerously altered proteins |
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Prokaryotes
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Prokaryotic:
No nuclear membrane around genetic material Cell walls - no peptidoglycan r-RNA, and lipids are very different from the bacteria Inhabit very inhospitable habitats, reminiscent of early Earth (hot, chemically hostile, anaerobic) Bacteria & Archaea |
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Prokaryotes:
Archaea |
Examples:
Methanogens Thermacidophiles |
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Archaea:
Methanogens |
Anaerobes harvest energy from CO2 and H20, produce methane as a waste product.
Inhabit the guts of ruminants (cows) and other animals |
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Archaea:
Thermacidophiles |
high temperatures (up to 85C)
harvest energy from sulphur compounds expelled at sulphur spring and geothermal vents. (including humans) and also at the bottom of marshes |
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Prokaryotes:
Bacteria |
Characteristics:
1) Unicellular, prokaryotic 2) Metabolically very diverse 3) Often a rapid reproduction rate e.coli's doubling time is 17 min 4) Act as primary decomposers and as pathogens (attack living or dead tissue) 5) Nearly omnipresent |
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Bacteria:
Classification |
1) Classified by mode by which they obtain energy:
Heterotrophs, Autotrophs 2) Classified need for O2 Aerobic, Anaerobic, Faculatative Anaerobic 3) Classified by structure of cell-wall Gram positive, Gram negative 4) Classified by shape Helix, Cocci, Spyrillis |
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Bacterial Reproduction and Genetic Variation:
Asexual Reproduction |
1) produce identical cells
2) effective way of propagating the genome in a stable environment (all genes get passed on to each offspring, not just 1/2 as in sexual reproduction) 3) If reproduction is rapid, even a low mutation rate will introduce some variation |
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Bacterial Reproduction and Genetic Variation:
Genetic variation |
Transformation
Transduction Conjugation |
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Bacterial Genetic Variation:
Transformation |
1) absorb DNA from the environment
2) DNA released when other cells die |
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Bacterial Genetic Variation:
Viral Transduction |
1) Virus accidentally carries bacterial DNA, NOT viral DNA
2) Injects into new bacteria 3) some genetic engineering accomplished in this way |
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Bacterial Genetic Variation:
Conjugation |
1) absorb DNA plasmids directly from another bacterium
2) Plasmid: small circular piece of DNA with a few dozen genes (also called an episome) |
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Bacteria in the global ecosystem:
Decomposition |
the breakdown of organisms and the release of nutrients back into the environment
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Bacteria in the global ecosystem:
Nitrogen Cycling |
Plants rely on nitrogen from the soil for growth and cannot acquire it from the gaseous nitrogen in the atmosphere.
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Bacteria in the global ecosystem:
Nitrogen Fixation |
Denitrifying bacteria
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Bacterial Human Diseases
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Pneumonia
Cholera Lyme Disease Gonorrhea (STD) Botulism E.coli |
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Protists
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any eukaryote that is not plant, animal, or fungus. 6000 protists have been described
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Steps from prokaryotes to Eukaryotes
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-membrane infolding
-endosymbiosis mitochondria/ chloroplast |
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Characteristics of protists
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-single-celled
-reproduce sexually or asexually -use all major modes of nutrition -photosynthetic protists (algae) -predatory protists (protozoa) -parasitic protists (protozoa) -systematics are in transition |
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Protists reproduction
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Protists exhibit a great deal of variation in their life
histories (life cycles). They exhibit an alternation between diploid and haploid phases that is similar to the alternation of generations found in plants. Protist life cycles vary from diploid dominant, to haploid dominant. |
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7 major groups of protists
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Chromists
Alveolates Slime molds Euglenoids Red Algae Zooflagellates Pseuopods Green algae |
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origin of plants
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green algae
-both have chlorophyll a and b and the accessory pigment B-carotene -both store starch -both share the composition and structure of sperm, thylakoids (membrane-bound compartment inside chloroplasts), and peroxisomes (metabolize fatty acids) |
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Steps from prokaryotes to Eukaryotes
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-membrane infolding
-endosymbiosis mitochondria/ chloroplast |
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Characteristics of protists
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-single-celled
-reproduce sexually or asexually -use all major modes of nutrition -photosynthetic protists (algae) -predatory protists (protozoa) -parasitic protists (protozoa) -systematics are in transition |
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Protists reproduction
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Protists exhibit a great deal of variation in their life
histories (life cycles). They exhibit an alternation between diploid and haploid phases that is similar to the alternation of generations found in plants. Protist life cycles vary from diploid dominant, to haploid dominant. |
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7 major groups of protists
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Chromists
Alveolates Slime molds Euglenoids Red Algae Zooflagellates Pseuopods Green algae |
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origin of plants
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green algae
-both have chlorophyll a and b and the accessory pigment B-carotene -both store starch -both share the composition and structure of sperm, thylakoids (membrane-bound compartment inside chloroplasts), and peroxisomes (metabolize fatty acids) |
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What land plants provide to other organisms
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oxygen, hold soil and water in place, build soil, moderate extreme temperatures and winds, and food
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4 phyla of land plants
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-bryophytes (mosses)
-pteridophytes (ferns) -gymnosperms (conifers/pines) -angiosperms (flowering plants) |
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4 great episodes in the evolution of land plants
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-origin of bryophytes from algal ancestors
-origin of diversification of vascular plants -origin of seeds -evolution of flowers |
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key features of plants
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-embryophytes- Multicellular plant embryos develop from zygotes that are retained within tissues of the female parent
-alternation of generations: two multicellular body forms (gametophyte and sporophyte) alternate -adaptations to life on land: -roots that anchor and absorb water -protection from desiccation (waxy cuticle and stomata) -vascular tissues -protection of gametes in enclosed structure (gametangia)- protection of the zygote and embryo -pollen, seeds, fruits, flowers -bryophytes: Gametophyte generation dominant - sporophyte develops from zygote, motile sperm swim to stationary egg on gametophyte, Early embryonic development occurs within archegonium, Haploid spores carried by wind, non-vascular - |
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bryophytes
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-Lack roots (absorptive structures called rhizoids)
-Limited conducting tissues -Gametophyte is dominant |
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ferns
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-vascular plants
-Sporophyte generation dominant - sporophyte develops from zygote motile sperm swim to stationary egg on gametophyte -Early embryonic development occurs within archegonium -Haploid spores carried by wind vascular |
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gymnosperms
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-Sporophyte generation is dominant - develops from zygote retained on gametophyte
-Wind dispersed pollen carries sperm to stationary egg -Early embryonic development occurs within a protective seed containing food supply -Seeds (2n embryo) dispersed by wind or animals -Vasular -Swimming sperm (which requires water for dispersal) was replaced by dispersal of the whole male gametophyte (pollen) -Gametophytes became even more reduced in size |
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angiosperms
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-Sporophyte generation is dominant - develops from zygote retained on gametophyte
-Pollen dispersed by wind or animals , carries sperm to stationary egg -Early embryonic development occurs within a protective seed containing food supply; seed encased in fruit -Fruit carrying seeds, dispersed by wind, water or animals -Vasular Important adaptations: -Flowers attract pollinators showy flowers advertise the presence of pollen -Fruits encourage seed dispersal fruits entice animals to transport seeds -Broad leaves capture more sunlight costs: attractive to herbivores (thorns, spines, and resins are produced to discourage herbivores) |
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Characteristics of fungi (8)
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1)Eukaryotic
2)Non-vascular 3)Reproduce by spores – sexual and asexual 4)Not motile 5)Alternation of generations 6)Uni- and multi-cellular 7)Cell walls 8)Differ from plants in cytoplasmic ultrastructure |
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fungi alterations of generations
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Sexual reproduction involves the two alternating processes of meiosis and fertilization. Meiosis and fertilization divide the life of the organism into two distinct phases or "generations".
-gametophyte generation -sporophyte generation |
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How fungi differ from plants
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-Fungi lack Chlorophyll and are not Photosynthetic.
-Fungi NEVER Reproduce by Seeds. -The Cell Walls of Fungi are made of CHITIN (KIE-tin), NOT Cellulose. |
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How lack of chlorophyll affects fungi
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-Not dependent of light – can therefore occupy dark habitats
-Can grow in any direction -Can invade substrate with absorptive filaments |
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fungi form
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-Body of almost all fungi is a “mycelium”
-Made up of an interwoven mass of hyphae -Septum -pores |
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nutritional status of fungi
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-Saprophytes
-Parasitism -Mutualism |
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Fungi reproduction
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-Most fungi produce enormous amounts of spores that are spread over a wide area
-Most produce both asexual diploid spores (mitosis) and sexual haploid spores (meiosis). -Spores can remain dormant until conditions become favorable for germination |
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4 major groups of fungi
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-Chytridiomycota (Chytrids)
-Zygomycota (Zygote fungi) -Ascomycota (Sac fungi) -Basidiomycota (Club fungi) |
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chytrids
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-Flagellated spores
-Cell walls contain chitin -Have contributed to the decline of the frog population worldwide |
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zygote fungi
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-Produce sexual diploid zygospores
-Cell walls contain chitin -Cause soft fruit rot and black bread mold |
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Ascomycota (Sac fungi)
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Sexual spores formed in sac-like ascus
-Cell walls contain chitin -Causes molds on fruit; textiles; Dutch elm disease and chestnut blight |
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Basidiomycota (Club fungi)
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-Sexual reproduction involves production of haploid basidiospores and club-shaped basidia
-Cell walls contain chitin -Causes smuts and rusts on crops -Include some edible mushrooms |
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Harmful Fungi
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-Can cause human disease, either directly or by their toxins
-Athlete’s foot and jock itch -Ringworm -Disease of important animals and crops -Rusts and smuts -Cause rot and contamination of food |
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Useful Fungi
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-Yeast: baking and brewing
Organic acids are produced with fungi: citric acid in Coke – Aspergillus -Steriods and hormones can be produced by fungi: The pill -Used to make fine cheeses: Camembert and Roquefort -Antibiotics: Penicillin |
