MODULE 1 OVERVIEW Flashcards
Define sexual reproduction
a mode of reproduction involving the fusion of one haploid gamete with
another haploid gamete to create a diploid zygote
4 types of sexual reproduction
1) dioecious vs monoecious/hermaphrodites
2) internal vs external fertilization
3) oviparous vs viviparous
4) few vs many offspring
Polyploidy can lead to. . .
speciation
Spores help in. . .
dispersal
surviving unfavourable conditions
genetic diversity
Why did aerobic respiration evolve?
- evolution of multicellularity
- larger organism + size
Why isn’t fermentation considered respiration?
it has no electron transport chain
What are the 2 hypotheses for how organisms evolved?
1) eukaryotic host engulfed AEROBIC prokaryote
2) prokaryote host engulfed a FACULTATIVE ANAEROBIC prokaryote
How do bacteria and archaea respire?
- obligate aerobic bacteria
- obligate anaerobic bacteria
- facultative anaerobic bacteria
What do anaerobic bacteria use instead of oxygen?
hydrogen sulfide + methane
How does aerobic respiration in fungi occur?
- in soil, hyphae absorb oxygen from TINY AIR SPACES b/w soil particles
- gases can move across thin outer wall of hyphae by absorption
How do plants obtain oxygen via diffusion?
1) stomata (leaves + stems)
2) lenticels (Stems of woody plants + some roots)
What are pneumatophores?
aerial roots in plants that are useful in anoxic or water-logged environments (Aerobic resp)
What are aerenchyma?
small air pockets in plant tissue
allow for exchange of gases from exposed parts of the plant to submerged parts
What are the 4 possible stages of RESPIRATION in animals?
- breathing
- gas exchange
- circulation
- cellular respiration
What are the 5 types of GAS EXCHANGE in animals?
- direct diffusion (small animals only)
- integumentary exchange (inv circulatory system)
- trachea
- gills
- lungs
How do insects use trachea?
- trachea are system of tubes branching throughout their body to provide oxygen to ALL cells
- opening to trachea called SPIRACES
- can be opened or closed when needed
- also muscle contractions help ventilate the tracheal system
How are gills involved in gas exchange?
- found in molluscs, annelids, crustaceans, and fish
- can be found in a cavity or externally
- highly branched w folded thin tissue filaments
Lungs in amphibians
simple sac like
Lungs in reptiles
sac-like, sometimes subdivided
Mammals lungs
branching lungs that terminate in tiny air filled sacs (alveoli)
Bird lungs
parallel series of tubes, the parabronchi
What are chemoautotrophs?
- bacteria make their own organic molecules using the OXIDATION of inorganic compounds
- majority live in a HOSTILE env
Anoxygenic photoautotrophs use. . . as a source of electrons
hydrogen sulfide
- are important for NUTRIENT CYCLING
2 features of algae (domain eukaryotes)
- multicellular + larger in size than plants
- require water (passively moved through cell walls)
Benefits of roots
- nutrient and water uptake
- anchorage + support
- plant hormones
Adaptations to living on land
1) roots
2) vascular tissue
3) cuticle
4) tissue for structural support
5) leaf types and size
Ingenious adaptations to get food for autotrophs
1) parasitic plants
2) carnivorous plants
3) symbiotic legumes (nitrogen fixing bacteria in root structures called root nodules)
4) symbiotic autotrophic algae
Empirical support for endosymbiotic theory
1) phylogenetically related
2) genome reduced
What are some heterotrophic feeding strategies?
1) diffusion
2) phagocytosis
3) filter feeding
4) parasitism
5) external digestion
What is filter feeding?
- straining organic matter and food particles from water, typically by passing the water over a specialized filtering structure
Disadvantage of parasitism?
- your food supply is entirely dependent on your host
- need to evolve structures that allow you to remain WITH the host
External digestion in fungi
- hyphae grow through the substrates
- secrete digestive enzymes which break down the substrate
- makes it easier for the fungus to absorb the nutrients which the substrate contains
External digestion in insects
- first tastes the food with its feet
- has sponge-like mouthparts that can suck up liquid, but are unable to chew larger sources of food
- secretes enzymes to digest food
Evolution of jaws in VERTEBRATES
- earliest fish = jawless
- jaws derived from gill arches
- jaws ==> teeth
What is secretion?
the movement of material that has a specific task after leaving the cell or organism
How does excretion regulate internal environment in 3 ways?
1) controls cell / body WATER CONTENT
2) maintains SOLUTE COMPOSITION
3) excretion of METABOLIC WASTE products and other UNWANTED SUBSTANCES
What is elimination?
the removal of unabsorbed food that has never been part of the body, typically in
the form of faeces
What happens if excretion can’t occur?
- disruption of cell membranes
- inefficient metabolism
- death
Mechanism of excretion in plants
1) transpiration
2) guttation (droplets of xylem –> sap) due to root pressure
3) storing in vacuoles
4) diffusion (thhrough root hair cells)
What are flame cells in animals and how do they assist with excretion?
- specialized excretory cells found in FRESHWATER invertebrates
- flame cells work like mammalian kidneys to remove waste
What are bundles of flame cells called?
protonephridia
early animals had them, later evovled into more complex nephridia
Why is the coelom important?
- fluid-filled so can be used as INTERNAL support
- SEPARATES internal processes from the gut
- allows TRANSPORT of FLUIDS (circulatory + excretory systems)
- provides space for DEVELOPMENT OF INTERNAL ORGANS
- enables INCREASED body size
Outline excretion in protists and early eukaryotes.
- single celled, no specialised organs
- passive diffusion, some active transport (and exocytosis)
Outline excretion in fungi
- no specialized organs
- passive diffusion + osmosis
- some active transport or exocytosis
The hindgut is involved in. . .
both excretion and elimination; N waste first moved into it prior to excretion
What is the relationship between ants and aphids (mutualism)?
- some species of ants farm aphids
- ants PROTECT aphids from predators
- ants are paid with honeydew released from aphids
- ants MILK aphids by stroking them w their antennae
Advantages of living in water
- support
- hydration
- nutrient rich
- environmentally buffered
Disadvantages of moving in water
- strong currents
- buoyancy (energy needed)
- water levels fluctuate
Adaptations to active movement in water
- cilia and flagella
- feet-like projections/structures
- fins and flippers
Adaptations required to take to the air
- light
- produce lots of seeds
- large surface area for lift
- enlarged muscles for flight
What are pseudopods (false feet)?
- Unicellular amoeba alter their cell shape by pushing cytoplasm outwards to
produce pseudopodia (false feet) - help to move in diff directions
When food is scarce, what do individual amoeba do?
aggregate to from a single
travelling colony (either as multiple cells or congregating to form a single massive
cell)
Flagella is used for. . .
locomotion
How do jellyfish (cnidarians) move?
- expanding and contrasting their bell-shaped bodies to push water behind them
- muscles assist in this process
How do molluscs (squid, octopus), move?
- take in water through their mouths then contract bodies to push water through their funnel to achieve forward propulsion
- muscles assist in this process
- tentacles also help in movement
2 features of molluscs
1) mantle - dorsal (back) body wall can form shell
2) muscular foot – used for moving, feeding manipulation
How do slugs and snails move?
by rhythmic waves of muscular contraction
secrete mucus
What are some adaptations of marine worms?
- free-swimming + sedentary
- unjointed leg-like parapodia
What are some adaptations of earthworms?
- most terrestrial and live in soil
- can grow very long
- react to vibrations
What are some features of vertebrates (subphylum of chordates)
- notochord
- dorsal nerve cord
- myomeres (segmented muscles)
The earliest fish has . . .
a cartilaginous skeleton
bony skeleton evolved later
How do fish move?
- using caudal tail and fins
- movement is active and assisted by muscles
- maintenance of buoyancy - essential to save energy
Features of cartilaginous fish
- large liver filled w low-density oil
- cartilage lighter than bone
- pectoral fins provide dynamic lift
Features of bony fish
- have a swim bladder of buoyancy
- swim bladder evolutionarily closely related to lungs (homologous)
What did legs evolve from?
evolved from long-rays of bone in fins of fish
these early amphibians had both gills and lungs
What were the first colonisers of the skies?
insects
How did wings evolve?
wings = stiff membrane of exoskeleton strengthened by ‘veins’
most likely evolved from gills in aquatic form
Relationship b/w reptiles and birds
archosaurs
What did birds evolve from?
dromaeosaurs
What are some adaptations of flight?
- bone LESS DENSE
- enlarged chest muscles for flight
- feathers system of air sacs in their body that connect to the lungs (allows for more oxygen)
How do fish and sprawling animals (like crocodiles and lizards) move?
from side to side
How do mammals move?
move the back half of the body forward and back (bends in a different plane)
Mammals evolved from . . .?
reptiles
and they walk upright
What changed in mammals and dinosaurs?
hip joints, and upper limb bones changed in mammals and dinosaurs
change of stance enabled QUICKER LOCOMOTION (longer legs)
Bipedal vs quadruped
humans walk upright (bipedal)
great apes typically knuckle walk (quadruped)
Changes in skeletal structure in humans vs gorillas
- big toe REDUCED
- pelvis SHORTENED, bowl-like
- femur bends INWARD
- knee STRAIGHTENED
- connection w spinal column on UNDERSIDE of skill
- LESS ROBUST upper arms
Human advanatage (compared to gorillas)
- upright walking freed hands for other purposes
- greater tool use
- ability to throw accurately
Sexual reproduction in fungi
1) plasmogamy –> dikaryotic organism (fusion of haploid cytoplasm)
2) karyogamy –> zygote (fusion of nuclei)
3) meiosis –> haploid spores
Fossil evidence suggests the first animal was similar to. . .
similar to a sponge
Biomarkers support. . .
the fossil evidence and suggest that animals had evolved by about 635 mya
What does fossil record help to understand?
determine the rate of origination and rate of extinction
Rate of origination / extinction can be used to understand. . .
diversity and identify adaptive radiations and mass extinctions
What is adaptive radiation?
when evolutionary lineages undergo exceptionally rapid diversification into a variety of lifestyles or ecological niches
most involve exploitation of a new environmental niche in the ABSENCE of competition
What is a mass extinction?
a statistically significant departure from background extinction rates that results in a substantial loss of diversity
