EXAM 3 LO

Identify adaptations that support aquatic life.

• Adaptations in evolutionary body plans

  • Radial, Bilateral, Asymmetric

• Ability to use O2 underwater

  • Gills, Diffusion, Lungs

• Mobility in a thick/gluey environment

  • Streamlined body shapes

  • Fins for locomotion

• Different feeding/predation strategies

  • Evolution of predation strategies due to Cambrian Explosion

Explore traits of basal invertebrates.

• Sponges (Porferia)

  • LACK TRUE TISSUES, no mesoderm

  • Asymmetrical body plan

  • Sessile as adults and sedentary as juveniles

  • Specialized cells for diffusion

• Coral,Jellies, Anemones, etc. (Cnidrians)

  • Radial symmetry body plan

  • No mesoderm, only ectoderm and endoderm

  • Specialized cells for function, sac-like structures for gastrovascular activity

  • Sedentary can move

  • No cephalization, only body

Examine the diverse body plans of mollusks.

• Gastropods:

  • Snails, Slugs, Nudibranches, etc.

  • Have a foot for mobility and movement

  • Have a thick spiral mantle for protection and structure

  • Radula for scraping, chewing, and biting as they have no mouth

  • Has coelomate with hemocoel for gas exchange and absorption of nutrients (open system)

• Bivalves:

  • Clams, Oysters, Mussels, Scallops, etc.

  • Have no foot for mobility but some have a retractable foot similar to it for movement

  • No distinct head

  • No nervous system or complex organ system

  • Have coelomate with hemocoel for gas exchange and etc. (open system)

  • Capture food through gills as they have no radula, filter feeders

• Cephalopods:

  • Octopus, Squid, Nautilus

  • Radial Symmetry

  • Well-developed sensory organs

  • Most complex and advanced of mollusk group

  • They’re hunters and predators

  • They have multiple appendages that aid in movement of water through jet propulsion expelling water through mantle cavity and explleing it

  • Closed system so they don’t have coelomate with hemocoel instead actual vein-like structures to distribute fluids

Describe the four key traits of all chordates.

• 1: They all have a notochord which aids in skeletal stability of chordates and mobility

  • Most similar to a spine in tetrapods

• 2: They have pharyngeal slits and clefts

  • These are gills in aquatic animals while in tetrapods adults lack slits/clefts

• 3: The presence of the dorsal hollow nerve chord that functions in the creation of CNS of aquatic chordates, it’s derived from the ectoderm

• 4: The presence of a muscular post-anal tail that functions in stability and locomotion of aquatic chordates, humans had one when they were fetuses but lost it

Compare common traits of early chordates.

• All chordates derived from a common ancestor with a head with 3 pairs of sense organs and a vertebral column

• Lampreys and Hagfish branch off into their own sista taxa as they’re both jawless and lack appendages and the retainment of their notochord during adulthood as they have no backbone

• The first clade consists of Cartilaginous fish, Ray-finned fish, Lobe-finned fish, and Lungfish that all share the trait of having a Jaw and 2 pairs of appendages

• The second clade consists of Ray-finned fish, Lobe-finned fish, and Lungfish that all share the trait of having a bony skeleton

• The third clade consists of the trait of having lobed fins with Lobe-finned fish and Lungfish

  • Ray-finned fish develop their trait of rayed fins differing from the other two fish

Consider the evolution of jaws as a driver of vertebrate diversification.

• The hypothesis on jaws was that: They developed from skeletal rods supporting gill slits

• They both have the same morphology and come from the same embryonic cells , but there’s still not enough conclusive fossil evidence to add truth to this claim

  • This allowed organisms like sharks to adapt to becoming predators as their jaws consist of sharp mineralized teeth

  • Organisms like ray-finned fish became the most diverse group of chordates after with the development of jaws and other factors aiding in their persistence and adaptability in different environments

• The evolution of jaws not only facilitated predation but also led to significant changes in feeding strategies, enabling these species to exploit a wider range of food sources.

Understand the impact of plants on ecosystems, species interactions, and human life.

• Plants are a diverse group of multicellular autotrophic eukaryotes

  • They’re a monophyletic group driving from a common ancestor

• They can function as decomposers, oxygen producers, and in nitrogen fixtation

• Plants are primary producers in ecosystems which a bottom-up effect on the chain if their role in an ecosystem was modified

Explore adaptations required for terrestrial life in plants.

• For plants to adapt to terrestrial life they needed several important adaptaions:

  • They needed to develop a waxy cuticle to aid in desiccation and water loss

  • Use of stomata to aid in gas exchange which also helped in maintaining water loss during photosynthetic processes

  • The use of flavonoids as a “sunscreen” against harsh sunlight

  • The relationship between mycorrhizae a fungi that helped plants in sufficient nutrient access and uptake, functioned almost as roots

  • The use of spores for reproduction and early dispersal by wind

Examine the transition from non-vascular to vascular plants.

• Bryophytes (seedless nonvascular) 470 MYA

  • Lacked vascular tissue for nutrient uptake, limits the size of these plants to shrubs

  • Reliance on damp environment water for sperm to swim through for reproduction

  • The use of rhizoids for anchoring rather than mycorrhizae

  • Lack of leaves and roots

  • Mainly haploid life plan, limits genetic diversity and variance

• Traecheophytes ( seedless vascular plants) 450 MYA

  • Had vascular tissue for nutrient uptake, increased size to big structures

    • Xylem: specialized in water transport and uptake through the help of lignin in cell walls

    • Pholem: specialized in the distribution of sugars, amino acids, etc. for plant growth

  • Sperm can move w/o the dependence of water

  • Have leaves and roots

  • Mainly diploid life plan, more diversity and variance

Analyze the evolution of seeds, flowers, and fruit and their role in plant diversity.

• Angiosperms ( seed vascular plants) 360 MYA

  • Use of seeds which are embryos protected by maternal tissue and w/ food supplies

  • Flowers are angiosperms with specialized shoots and modified leaves

  • Flowers attract pollinators, pollinators take pollen aiding in dispersal

    • Mutualistic relationship

  • Pollen protects male gametes

    • Gametophyte makes pollen, gamete is surrounded by pollen wall

    • Doesn’t require water for sperm reproduction, allows for more genetic diversity

  • They have fruits which are mature embryos, aiding in dispersal

    • Fruits develop from ovaries and contain seeds that protect the embryo and provide nutrients, ensuring successful germination and establishment of new plants.

  • Flowers and Fruits are under mutualistic selection from animal

Examine how the evolution of seeds, flowers and fruit increased plant diversity

Review transitions in plant groups over time

Consider the role of plants in your daily life

Investigate how mycorrhizae improve plant productivity

Explore how plant-animal mutualisms support plant success

Describe how herbivory had led to diverse plant defenses