Biol2200 Exam 3! YAY!

Identify adaptations that support aquatic life

-DIVERSE body plans

-Acquiring oxygen in water -Mobility in viscous environments

-Diverse ways to feed

Sponge Traits

-before bilateral symmetry

-porifera

-asymmetric body plans

-sessile as adults

-lack true tissues: have differentiated cells, but no tissue

-no multiple germ layers

-metabolic processes by diffusion

Cnardia Traits

-Jellies/ jellyfish/ coral/ anemones

-radially symmetric

-2 true germ layers with an endoderm and ectoderm

-sac with a gastrovascular cavity (not like a mouth and anus)

What are mollusks defined as?

marine protostomes

3 types of mollusks

gastropods, bivalves, cephalopods

Traits of Gastropods

-(snails, nudibranch/shell-less)

-Can be found on land

-Radula: mouth part that can graze, scrape, and chew, looks like a cheese grater

-Stomach in its foot

-Most have a single spiral shell

-Coelomate with hemocoel Both a coelom and a second body cavity called a hemocoel which holds blood: holds digestive and respiratory organs

Traits of Bivalves

-scallops

-no distinct head (suggests that the ancestor had a head at some point and lost it)

-some have sensory organs

-filter feeders, feed through gills, no radula

-coelomate with hemocoel

Traits of Cephalopods

-squids, octopus, nautili

-gained a number of adaptations

-marine hunters (not just predators)

-well-developed sensory organs

-jet propulsion by water expelled from mantle cavity (pulls water in and squirts it out very fast)

-closed circulatory system (no hemocoel)

What is the significance of having a hemocoel as a primary body cavity?

most mollusks have no blood vessels, so blood must be in direct contact with organs that facilitate nutrient acquisition and gas exchange

All chordates are...

coelomates ( we are chordates )

4 key traits of chordates

Notochord, Pharyngeal clefts and slits, Dorsal Hollow Nerve Chord, Muscular post anal tail

What is a notochord?

- exists in all embryos of chordates, but only some adults

- longitudinal, flexible rod that is derived from mesoderm

-provides skeletal support

exists in animals that lack a spine

What are pharyngeal clefts and slits?

arches along the pharynx that develop into slits

-different fates depending on type of organism:

- invertebrates- suspension feeding, pull water over slits and filter out microparticles

-aquatic vertebrates- gills

-tetrapods- no adults have slits

what is a dorsal hollow nerve chord?

-close to outside of body

-germ layer origin: ectoderm

-hollow tube that develops into CNS (aka brain and spinal column)

what is a muscular post anal tail?

in non-chordates, digestive tract runs the body length: post anal tail ends at the post anal (duh)

-reduced in adult chordates (not in dogs, cats, etc)

Lancelets

One of a group of invertebrate chordates:

-notochord protects dorsal hollow nerve chord

-filter-feed using pharyngeal slits

-most basal, attain all traits into adulthood

tunicates

-larvae reflect chordate characters

-adults become sessile (like sponges)

hagfish and lamprey

-rudimentary vertebrae: no backbone or spine

-retain notochord because rudimentary vertebrae run through back of body

-notochord into adulthood

Cambrian explosion and its effects on evolution of chordates

535 MYA

- rise in o2 levels

- receding glaciers

- appearance of diverse body plans

- emergence of predators: prey now have to defend themselves

evolution of jaws

driver of vertebrate diversification:

-Rapid radiation of jawed fish after jaws appear

-Hypothesis: jaws originated from he skeletal rods that support gill slits

plant traits/ associations

-closest relative are charophytes (green algae)

-photosynthetic

-chloroplast have chlorophyll a and b

-protein rings that synthesize cellulose

-unique flagellated sperm structure

-Unique structure during cell division- phragmoplasts: structure associated with the division of cytoplasm during mitosis

why did plants first move from water to land?

more co2, light, nutrients, habitats, and low competition

challenges of plants on land

-loss of water/ desiccation

-too much sun

-natural disasters

-new pests/predators

adaptations of plants for land

-different groups have different strategies for life on land

-prevention of water loss (waxy cuticle, stomata)

-UV protection

-access nutrients efficiently (Developing relationships to access nutrients)
-protect spore from environment (dispersal)
-protect embryos from environment (tissue barriers)

-change life cycle

flavonoids

UV absorbing compounds that prevent DNA damage in plants

more subtle plant adaptations to land

-protection of embryos from environment

-protection of spores from environment (spore coat protects from dry environment)

-alteration of generations (multicellular DIPLOID and HAPLOID life stages)

when was the first evolutions of land plants?

470 MYA

Bryophytes

liverworts and mosses

-lack vascular tissue (aka limits height)

-no specialized cells to transport water and nutrients

-lacks roots-> less nutrients acquired

characteristics of early non-vascular land plants

-bryophytes

-sperm traveled through water (need a damp environment )

-dispersal by spores

-dominant lifestage is haploid, not diploid (less genetic variation)

when did vascular plants evolve

425 MYA

vascular plants

• Xylem

  • Water-conducting cells

  • Lignin provide structural support

• Phloem 

  • Distributes sugars, amino acids, products synthesized by plan

• Roots absorb water, nutrients

• Leaves increase photosynthesis 

  • Leaves increase the surface area that plants need to acquire something

seedless vascular plants:

-resources are transported through the vascular system

-increased height due to vascularization

-roots and leaves (leaves increase photosynthesis)

-diploid dominant life stage (more genetic variation)

-mosses and ferns

Xylem

water-conducting cell tissue

-lignin provide structural support

Phloem

-vascular tissue

-distributes sugars, amino acids, and other organic products

-targets specific parts of body

Unlike seedless vascular plants, seed plants have...

-Seeds to protect embryos

-Pollen to protect male gametes

-Spores enclosed in reproductive structures

seeds - dispersal distance

-embryos with food supplies and a protective coat

-disperse long distances and survive in harsh conditions

pollen - genetic diversity

-male gametophyte (structure that makes gametes) is surrounded by pollen wall

-does not require water to travel and fertilize egg

describe the relationship between sperm, seeds, spores, and pollen

all plants have sperm and spores, but not all have seeds

all plants have sperm, but not all have pollen

How do plants disperse before the evolution of seeds and pollen?

plants dispersed via spores, which were carried by wind or water

How does the evolution of seeds and pollen change dispersal?

enabling reproduction without water, increasing survival rates, and facilitating wider distribution through wind and animals

why do seed plants have higher diversity

Speed dispersal more effective than spore dispersal

Pollen increases genetic recombination- genetic diversity

-seed plants are the only pollen plants

angiosperms

flowering plants

-fruits that surround and aid in seed dispersal

-mutualisms with animals (increase fitness)

gymnosperm

a woody, vascular seed plant whose seeds are not enclosed by an ovary or fruit

what is the fleshy part of the fruit

maternal ovary tissue

importance of plants

• Provide foundations for ecosystems

• Production of biomass, oxygen, nutrient cycling etc.

• Important to trophic levels above them (source of food)

• Provide structural support 

• When they die, they decompose and feed new plant material 

plant timeline:

-red algae

-chlorophytes

-charophytes

-bryophytes (first land plants - liverwort, moss, hornwort)

-seedless vascular plants

-gymnosperms

-angiosperms

plants as medicine

treat pain (morphine), cancer (taxol), heart disease (digoxin)

plant-plant interactions

plant species have intense competition, allelopathy, and facilitation

plant-animal interactions

pollinators, dispersers, and herbivores

how do mycorrhizae improve plant productivity

-symbiotic relationship between plants and fungi

-fungi increase nutrient uptake

-plants provide fungi with carbs

specifically, mycorrhizae helps plants grow huge

pollination benefits

-movement of pollen by animals increases likelihood of mating: very specific unlike wind dispersal

seed/fruit dispersal benefits

movement of embryos by animals increases range and habitat diversity: improves ability to move to new habitats and provides fertilizer for the plants

herbivory benefits

-plant/animal antagonism

-herbivores have a significant impact on plant fitness

-plants start to produce physical or chemical defenses against herbivory

-some plants develop mutualisms with body guards to stop attacks

As animals moved from aquatic to terrestrial environments, what challenges did they face? (6)

Water loss, gravity, uv light, gas exchange, reproduction, different weather conditions

main animal adaptations to life on land

exoskeletons, gas exchange structures, reproductive strategies

exoskeletons

prevent water loss

-protect from UV rays

-provides structural support

Gas exchange structures

diffusion: simple invertebrates (sponges, jellies) mostly in moist

gills: invertebrates, in water only

reproductive strategy variation with adaptation

shift to internal fertilization: Fertilization used to be just letting sperm go out in the water: this doesn't work on land

general characteristics of arthropods

paired jointed appendages, exoskeleton made of chitin, well-developed sensory organs, coelomates with reduced coelom, open circulatory system, gas exchange in terrestrial arthropods

non-insect arthropods

• Spiders and ticks (Chelicerates)

  • Predators and parasites

  • 6 pairs of appendages (8 legs)

• Myriapods (many feet)

  • Millipedes → 2 pairs legs/segment

  • Centipedes → 1 pair legs/segment

• Crustaceans

  • Mostly aquatic, except isopods

  • Isopods are important decomposers 

what is the main body cavity of arthropods?

hemocoel

gas exchange in chelicerates

book lungs

-strcture of folded tissues that help with bringing oxygen into body

gas exchange in insects

trachea (tubes) deliver O2 directly to organs

non-insect arthropods

-spiders and ticks

-myriapods (many feet)

-crustaceans

key characteristics of all insects

-6 legs

-flight (most)

-metamorphosis

-sexual reproduction with internal fertilization

-terrestrail habitats

-diverse mouthparts

Metamorphosis

incomplete: larvae resemble adults, smaller, wingless (cockroaches)

complete: larvae distinct in phenotype, diet, habitat from adults (butterfly, moth, beetle)

Some insects have different larval habitats such as...

aquatic: mosquitos and dragonflies

underground: beetles

reproductive strategies

• Sexual reproduction is common

  • Internal fertilization supports reproduction on land

• Some insects have asexual reproduction

Diversity of mouthparts:

Butterfly- nectar (tubular flowers)

Cicada- xylem

Bee- nectar (open flowers)

Grasshopper- leaves

ecological impacts of insects (3):

insect pollinators are critical for producing fruits and vegetables ($200 billion)

-pest controllers: predatory and parasitic insects can control herbivores in crops

-decomposers: nutrient cycling

Pests and disease insects:

Voracious herbivores: insect pests can decimate crops, increased resistance to pesticides

Vectors of disease:

mosquitos- malaria, zika, yellow fever,

kissing bugs- chugs disease,

tsetse flies- African sleeping sickness

which of the following arthropod traits played a key role in the transition to life on land?

internal fertilization

3 multiple choice options

what happened after jaws first appeared

rapid radiation of jawed fish

hypothesis of jaws

jaws originated from skeletal rods that supported gill slits

-jaws and rods have similar morphology

-jaws and rods derived from the same embryonic cells

adaptations in sharks

skeleton of cartilage, mineralized teeth, adapted for hunting

adaptations of ray finned fish

most diverse group of vertebrates

-first fully mineralized skeleton

-swim bladder maintains buoyancy (derived from lungs)

lobe finned fish

coelacanth, lungfish

-bones in front fins that resemble wrists

-closest living relatives to tetrapods

tiktaalik

-true transitional species between life in water and on land

-more derived bones in wrist

-presence of a neck

-developed rib cage

-large pelvis but not strongly connected to spine (challenge of gravity on land)

when do marine mammals evolve

after land mammals

when are tetrapods in the fossil record and what groups do they involve?

365 MYA

amphibians, mammals, reptiles

what adaptations did vertebrates need to succeed on land?

-new way to move

-increased skeletal support

-new gas exchange methods

-strategies to prevent water loss

derived traits of tetrapods

-limbs with legs

-head separated from body via neck

-bones of pelvic girdle fused to backbone

-adults lack gills: changes to gas exchange organs

amphibian traits

larvae are aquatic

moist skin facilitates gas exchange (some species lack lungs altogether)

external ferilization in water or moist environments

salamanders

-amphibians

-some entirely aquatic, some terrestrial

-some use cutaneous gas exchange (exchange at skin)

frogs

-aquatic larvae distinct from adults

-toads are not monophyletic

-known for vocalizations, aposematism (defense strategies using signals like vocalization or color)

relative to other species that predate tetrapods, what traits make tiktaalik a transitional species?

BONES IN FINS

draw the amniotic egg- label the four membranes

• Amnion directly protects embryo during development; fluid-filled cavity 

• Yolk sac holds the yolk (nutrients that have been provided by the parent) so the embryo has what it needs

• Allantois: Where we store metabolic waste → where to place toxic compounds away from the body so it doesn’t affect embryo’s development

• Chorion is semi-permeable to facilitate gas exchange 

3 derived traits of amniotes

-eggs with shells or internal gestation (reduced water loss of developing embryo)

-less permeable skin (reduced water loss of adults)

-rib cage used for ventilation (get more air, efficient gas exchange)

reptile traits

Scales/feathers containing keratin: prevents desiccation

Lay shelled eggs on land- Internal fertilization prior to shell secretion

Vary in temp regulation strategies

Snakes/lizards are ECTOTHERMS

Birds are ENDOTHERMS

lizards

from a few cm to 3+ cm

broad diet reflected in teeth

snakes

lizards -> snakes (loss of legs)

-adapted for hunting (some have venom)

turtles

-shells fused to vertebrae

-terrestrial, freshwater, and marine

mammal derived traits (6 things)

-Mammary glands

-Hair- from keratin

-Fat layer under skin Endotherms

-Larger brains

-Extended parental care

- Diverse teeth

monotremes

platypus, echidna

-lay eggs (external gestation)

-have mammary glands but lack nipples

marsupials

opossums, kangaroos

-simple placenta (not nutrient rich)

-complete embryonic development outside uterus

eutherians

placental mamals

-bears, marine mammals, giraffes

-complete placenta

-development in the uterus

-longer gestation time

derived traits of primates

hands and feet adapted for grasping

-flexible digits

flat nails instead of claws

large brains and short jaws (in comparison with organisms of same size)

eyes look forward- hand eye coordination (predators have forward eyes)

what trait is unique to monkeys and apes

flexible or opposable thumbs Most known trait Grasping more effective with thumbs

hominins

hominids excluding the African apes; all the human species that ever have existed (share a common ancestor with chimps, but did NOT evolve from chimps

hominids

Creatures that walk upright