Lecture 16-30 Flashcards
What is evolution?
Evolution is the process by which the heritable characteristics of a population change over time.
- all evolution must occur on the genetic level
What is a population?
A group of organisms of the same species in the same region capable of mating freely with one another
What is a character or characteristic?
A feature of an organism (e.g. hair color, nose shape, height, blood group)
What is a trait?
The state of a character in an organism (e.g. blonde, narrow, 178cm, AB+)
What is a Phenotype?
All the observable traits of an organism. These result from the interactions of its genotype (genetic inheritance) with the environment.
What are evolutionary genetics?
Broader study of how population genetic phenomena bring about long-term evolutionary change, including speciation and adaptation
What are Mendel’s 3 laws of inheritance?
- Law of segregation (the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene)
- Law of dominance (some alleles are dominant and some are recessive)
- Law of independent assortment (genes from different traits segregate independently during the formation of gametes)
What are examples of monogenic discontinuous traits?
Hair lines, dimples, chin clefts
What is an example of a polygenic trait?
Skin color is an example of a polygenic trait
- these traits are often continuous - a large range of phenotypes not easily categorized
What is a mutation?
A stable, heritable alteration in the genetic material and the raw material of evolution
What is recombination?
The rearrangement of DNA sequences by the breakage and rejoining of chromosomes
What are alleles?
alternate versions of the DNA sequence that occur at the same locus on homologous chromosomes
What is a population bottleneck?
Reduction in overall population size (e.g. due to environmental stress like a famine)
What is a locus? (on a chromosome)
it is a fixed position on a chromosome
When is genetic drift stronger?
it is stronger in smaller populations that are more affected by a mutation.
- random drift is weaker in larger populations
What is the founder effect and what does it do?
isolation of a small fraction of the population from the larger group (gets rid of a trait possibly)
What are the two things that offspring must be?
- Viable: the individual must reach adulthood
- Fertile: the adult must be able to have offspring
What is admixture?
gene flow between two or more genetically distinguishable populations
What is a molecular clock?
The observation that amino acid differences between species accumulate at a regular (clock-like) rate.
How do we estimate the fitness of different genotypes?
We calculate the average number of offspring left by individuals with each genotype
What can the molecular clock be used to tell?
It can tell us when species diverged or their estimated times, even when there is no fossil evidence.
What is the neutral theory of evolution (1968, Kimura)?
- Neutral alleles have no impact on the organisms fitness
- neutral alleles will change in frequency by genetic drift alone
- most substitutional events observed occurred by drift not by selection
- still allows for some selection
- Supported by empirical data: molecular clock between species
What is Anagenesis?
Evolution of a new species without branching
What is cladogenesis?
An evolutionary splitting of one species into two descendent species
How long can DNA last or be preserved?
It can last around 2.6 million years (that’s the limit of permafrost)
What are the major aims of phylogenetics?
- to reconstruct the correct evolutionary relationships between biological entities
- To estimate the times of divergence
- to escribe the sequence of evolutionary changes
- to locate the geographical origins
What is a clade?
A group of taxa composed of a common ancestor and ALL of its descendants
What are the parts of a phylogeny?
Nodes: represent taxonomic units, DNA sequences, genes, proteins, individuals, populations etc.
Branches: define the relationship between nodes, descent and ancestry
Operational taxonomic unit: actual data under study
Hypothetical taxonomic units: inferred ancestral unit
Root: recent common ancestor of all units under the study
What is Introgression?
the transfer of genetic material between species or subspecies through a hybridization event followed by backcrossing with the parental species
What are examples of a recessive disorder?
Cystic fibrosis and albinism
What causes higher frequency of recessive disorders?
Close inbreeding increases the frequency of both common and recessive traits
- The founder effect and bottlenecks can also increase this
What is metabolism?
The sum total of all chemical reactions occurring in an organism, it concerns management of energy
What is cellular respiration?
the burning of fuel to produce ATP (life’s energy molecule)
The four main steps are:
1. Digestion (catabolism)
2. Glycolysis
3. krebs
4. ETC
What is metabolic rate?
The sum of all the energy an organism uses in a given period of time.
What is metabolic rate influenced by?
- Body size
- Temperature
- Activity
etc…
Why do bigger animals require more energy?
They require more energy because they have more cells which require more energy
- per unit mass metabolic rate decreases for larger animals
What does temperature do to metabolic rate?
For ALL organisms it exponentially elevates their metabolic rates, metabolic rate doubles or triples for every 10c increase
What are the different properties of water potential in plants?
- osmotic potential
- Pressure potential
- matrix potential
- Gravitational potential
How do plants get the nutrients they need?
Semipermeable membranes!
- allow for the passage of some molecules and ions but not others
- osmosis occurs
- Water moves from high to low psi, which is energetically favorable
What allows plant cells to be able to handle high pressures?
Rigid cell walls allow plants to handle high pressures
- composed of cellulose, hemicellulose, pectin
What do heterotrophs/ animals need food for?
- Fuel (chemical energy)
- Raw materials for biosynthesis (carbon skeletons)
- Essential nutrients
What fuels ATP generation?
Carbohydrates and fats fuel ATP generation
What are the four types of essential nutrients?
- Essential amino acids
- Essential fatty acids
- Vitamins
- Minerals
What are amino acids and what do animals need?
All organisms need a standard set of 20 amino acids, plants, microorganisms can typically synthesize all of them
- 50% need to come from diet
- protein in animal products complete, most plant protein incomplete
What are Fatty acids and what do animals need?
they synthesize a variety of cellular components (e.g. membrane phospholipids, storage fats)
- can synthesize many fatty acids but several must come from diet
- Dietary seeds, grains, vegetables
What are vitamins and what do animals need?
organic molecules required in relatively small amounts of the diet, diverse physiological functions
- Coenzymes in metabolic processes
- Formation of visual pigments
- Bone formation
- Blood clotting
- Synthesis of fat
What are minerals and what do animals need?
Inorganic nutrients needed in smallish amounts
- Many metabolic processes
- Acid-base balance
- Nerve and muscle function
- Calcium and phosphorus needed in relatively large quantities for construction of bones
What are adaptations that humans have in their digestive system?
- Efficiency of digestion and absorption (70-80%)
- Dentition: teeth
- Size and length of digestive system (larger digestive tract = more time to digest plant cell walls
What are plants made up of and what is there biomass?
- Carbon 30-50% of plant biomass is carbon, building block of metabolites, enhances growth
- H2O 405 of plant biomass is oxygen, critical for cellular respiration
What are essential plant nutrients?
Macronutrients:
- Nitrogen, magnesium, phosphorus, Sulfur, Potassium, Calcium
Micronutrients:
- Boron, chlorine, Manganese, copper, iron, nickel, zine, molybdenum
What does resource allocation depend on in plants?
- Environmental cues
- Genetic constraints
- found in Transport tissue, photosynthetic tissue, reproductive tissue, roots
Where are micro and macronutrients obtained from?
They are obtained as ions from the soil
What is the difference between micro and macronutrients?
Macro = structural components of proteins, cell walls, membranes, metabolites, and chlorophyll (osmotic potential)
Micro = enzyme cofactors, forming active sites
What are the routes that nutrients can take to enter the cell?
Apoplastic route - between cells
Symplastic route - through cells via plasmodesmata
What happens in Nitrification?
Soil bacteria further convert ammonium to nitrate
What does Magnesium do for plants?
it is the lynchpin of chlorophyll by stabilizing structure during light capture, it is also related to energy transfer (e.g. ATP activation)
How is phosphorus important in plants?
Phosphorus is the key for the production of ATP, very high energy bond
What are other ways that plants can get their resources?
Carnivory - some plants supplement their dietary needs by finding a way to trap insects
Parasitism - Some obtain nutrients and organic carbon by growing in or on other plants
What is an example of a parasitic plant?
Mistletoes are an example of a parasitic plant, their seeds germinate on other plant structures. After establishing on the plant a connection forms between the phloem and the xylem.
What are proteinases?
digestive enzymes that break down proteins during digestion
What do prostaglandins do in plants when there is a stress response?
They regulate inflammation to repair tissue damage.
- Salicylic acid
- Plants respond to their injuries and enemies a lot like animals do
What are Proteinase inhibitors?
Prevent digestive breakdown thus reduce digestibility
What are abiotic stressors to plants?
Temperature - too hot or cold
- Heat-shock proteins
Drought stress (can be regulated by phytohormones)
-
Why do we have circulatory systems in animals?
Because diffusion is inefficient over large distances, some simple animals don’t have true circulation systems
What are the functions of the circulatory system?
- Respiratory transport
- Nutrient and water transport
- Communication via hormones
- Infection fighting
- Wound healing
- Heat transfer
What are respiratory organs for gas exchange?
- Gills
- Lungs
- Skin
What is an open versus closed circulatory system?
Open = pores, tubular heart, Arthropods (some mollusks)
Closed = Small branched vessels in each organ, Auxiliary hearts. ventral vessels, dorsal vessel (Annelids, All vertebrates, some mollusks)
What is special about echinoderms (example starfish) - respiration?
They use their vascular system for respiration and locomotion
What are different ventilation patterns?
- Non-directional
- Tidal ventilation
- Unidirectional ventilation
What is Tidal ventilation?
- Enter and leave through the same points
- e.g. humans, reptiles
What is Unidirectional ventilation?
One way flow, more efficient
- birds and fish
What are abiotic factors?
- Temp
- water
- sunlight
- wind
- rocks and soil
- periodic disturbance
What are the two factors that plants need to cope with?
- Stress: light, water, nutrients
- Disturbance: partial or total destruction of plant e.g. herbivory, wind, frost, fire etc.
What can closed circulation be?
Single:
- Low flow
- Low blood pressure
- metabolic performance
Double:
- 2 loops
- heart pumps blood to the lungs, then blood comes back to the heart
- provides a lot of energy
- costs a lot of energy
What are the two native flowering plants found in the Antarctic region?
- Deschampsia antarctica (Antarctic hair grass)
- Colobanthus quitensis (Antarctic pearlwort)
What are the problems of dep sea survival?
- Extreme pressure
- Darkness - hard to find prey and a mate
- Extreme cold - around 1c or less at 4000 m
What are characteristics of deep sea fish?
- small and gelatinous
- reduced skeleton
- no swim bladder or other air spaces
- deep sea fish often explode when brought to the surface
- THINK blobfish
What is competition?
Interaction where different individuals/species compete for a limited resource
- Nutrients
- Breeding sites
- Food
- Space
What is Plant competition?
The tendency of neighboring plants to utilize the same quantum of light, ion of a mineral nutrient, molecule of water, or volume of space
What is Mutualism?
an ecological interaction between two species in which both benefit
(crocodile and birds, shark and feeder fish)
What is commensalism?
an ecological relationship in which one species benefits while the other is not harmed or helped in any significant way
What is Amensalism?
Competition with no effect on winning competitor
What is parasitism?
ecological relationship where a parasite eats the cell contents, tissues, or body fluids of the host
- parasites harm but usually do not kill their hosts, at least not immediately
What is an ecological niche?
the specific set of biotic and abiotic resources that an organism uses in its environment
What is the difference between fundamental niche and realized niche
Fundamental: full range of environmental conditions, resources and space
Realized: where the species actually occupies in the world
What is an animal with an ecological niche?
Poisonous dart frog = good example
- Lives in rainforest
- high temps
- breeds in bromeliads
- eats insects
- high humidity
(two species can have the same ecological niche)
What is resource partitioning?
When two species with similar niches take up/use different spaces (higher and lower parts of a tree)
What is obligate mutualism?
One species cannot survive without the other
What is Facultative mutualism?
Where both species can survive independently
What is the energy flow through the ecsystem?
sun - producers - consumers - decomposers - inorganic nutrient pool
What can save the planet?
- Climate regulation
- Dwindling fossil fuel
- Feeding global population
- Maintaining biodiversity
What are the layers of soil?
O: litter layer
A: Mineral soil mixed with organic matter
B: Depositional horizon containing materials leached from A horizon
C: weathered parent material
What is the biosphere?
The entire proportion of Earth that is inhabited by life; sum of all planets communities and ecosystems
- Seas, lakes, rivers/streams etc.
What are geographical regions that are connected to a biome?
- Tropical forest
- Desert
- Grassland
- Temperate forest
- Boreal/coniferous forest
- Tundra
What is climography?
The relationship of climate to biomes
What is primary productivity (biome productivity)?
Rate at which biomass is produced per unit area by plants
What is Net primary productivity (biome productivity)?
What is left after some primary productivity has been respired away by plants themselves
- Net primary productivity represents the actual rate of production of new biomass
What are the 3 types of tropical forests?
- Tropical rainforest
- near equator (rainfall: >2,500 mm/yr)
-25% of forests in tropics, 6% of earths surface - Tropical Deciduous forest
Areas with distinct wet and dry season
- trees and shrubs
- 32% forests in the tropics - Tropical dry forest
- lowland areas with prolonged dry season and scarce rainfall
- thorny shrubs
- 43% tropical rainforests
What are Epiphytes?
plants that live on plants (not parasites)
What is a Boreal forest? (northern conifer forest, Taiga)
Winter: long and cold (short day length
Summer: short and wet (warm)
Soil: thin, nutrient poor and acidic
principle trees: conifers - can withstand cold drought and snow
What are temperate forests?
Mid latitudes where sufficient moisture to support trees
Summers: warm
Winters: cold
Growing season: 6-9 months
precipitation: relatively high and throughout the year
Soil: deep and fertile, thick litter layer
What are Grasslands characterized by?
Long seasonal drought
What percent was the natural grassland originally?
42% of land surface was
What is temperate grassland?
- When rainfall is intermediate between desert and temperate forest biomes
- long dry season
- cold winters (dormant period)
- grazing and occasional fires
- fertile soils
What are Tropical grasslands?
- Warm climate
- Long dry season (5-7 months)
- Regular fires (every year)
- Lower nutrient status then temperate grasslands
How is desert location determined?
By global atmospheric circulation but also, rain shadows and continental interiors
What are plant adaptations for the desert?
- Avoid drought - carefully timed phenology (seasonal flowering)
- Tolerate drought
- intesnsification of water absorption, shallow spreading roots, really deep roots, dew/fog traps
- Reduction of transpiration
What are some ways that plants reduce transpiration to tolerate drought?
- Sunken stomata
- reduce stomatal aperture
- scaly/hairy leaves
- retain dead leaves around stem
- deciduous, shed leaves/branches
What is Tundra climate like?
Physical:
- cold
- low precipitation
- permafrost
- short-growing season
Botanical:
- very low diversity
- perennials with vegetative reproduction
- no trees
- shallow rooting
What is peat?
Partially decayed organic matter of plant origin formed under wet, anaerobic conditions
- found in areas of high rainfall and impeded drainage
What are Bog characteristics?
- Very low nutrients
- Waterlogged
- Acidic
What is species richness?
the number of species in a given area
What is species evenness?
The relative abundance of species in a given area (how rare or common a species is)
What is Diversity Index?
Overall measure of diversity that combines aspects of richness and evenness
What percent of the worlds fish species live in rivers?
40% of fish species
What kind of rivers are there?
- Snow fed rivers
- Glacial rivers
- Bog fed rivers
What are different stressors for rivers?
- Dams block migration routes and disrupt habitat
- Overexploitation
- Global warming, pollution, drought
- Eutrophication from agricultural and urban areas
- Water withdrawal for human use
- Invasion of exotic species
What are some anthropogenic sources found in rivers?
- Manure
- Fertilizer
- Sewage treatment
- Acid rain
What happens when land around rivers is agricultural?
- Dissolved nutrients increase (nitrogen and phosphorous)
- Deposition of fine sediment increases (cattle disturb the bank)
- Water temp increases (loss of shading along the river bed)
- Water input decreases
- Chemical pollutants increase
What is an example of an invasive water species (mollusk)?
Zebra mussel
- native to Caspian and Black sea region
- spread by boat movements
one female mussel can have up to one million eggs over year
- Can live without water for 7 days
- they are very efficient filter feeders which means they remove the nutrients from the water/food for other animals
What do we use the ocean for?
- Tourism
- Food (fish etc.)
- New innovation’s
- Genetic resources
- Cultural
- Pollination
- Raw materials
- Recreation
- Climate regulation - carbon storage, storm protection, waste breakdown
- Food web
- SO MANY THINGS
What are the layers of marine habitats? Surface to bottom
Intertidal, Pelagic, mesopelagic, bathypelagic, Abyssopelagic
How many animal phyla are found in the ocean?
- 30 animal phyla are found in the marine system, 600,000 to 9 million species associated with tropical coral reefs
What is an estuary?
Where the river meets the sea, they are difficult to define (based on salinity)
What are the classifications of estuaries?
- Topography: coastal plains, offshore deposits, isostatic variation driven by tectonic activity
- Tidal range: large tidal ranges
- Environmental characteristics: salinity, sediment, dissolved oxygen, temperature
What is a tidal prism?
The difference between volume of water when tide is in and out
What organisms would you expect to find in estuaries?
Head = freshwater, e.g. chironomids, fish
Upper = polychaetas, nematodes, crustaceans, fish and bivalves
Mid(mud) = like the one above
Outer = bivalve beds (mussels, oysters), migrators like eels and salmon
Not very many plants
Why are estuaries important for fish?
They’re are some species that live primarily in estuaries
- its a good nursery for fish
Why is the Dublin Bay so important?
- Coastal, intertidal and subtidal habitats
- Water quality generally good
- Important wetland habitat
- Protected by legislation
- High commercial and cultural value
What is a citinental shelf?
Low water to 200 m depth
- extends from land to shelf break
What are Bioturbators?
- Burrowers (worms and shrimp) and bulldozers (gastropods and starfish)
- They increase the complexity of the substratum surface by creating pits and mounds
- Enhance gas exchange of O2
What does permafrost store?
it stores carbon, twice as much in permafrost than the atmosphere
Why is Seagrass important to ecosystems?
- Home to many micro algae and bacteria
- One acre can support 40,000 fish and 50 million small invertebrates
- Not a seaweed (has roots and flowers)
Reproduces both sexually and asexually
What does genetic diversity influence?
- Behavior of ants
- Genotypic richness of the leaf litter influenced decomposition and nutrient flux community
- Evolution
