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Title: Biology - Evolution and Ecology
Description: Includes my notes for Chapters 31-34 and 53 for the third exam in my class. In my case the exam was not cumulative so only those chapters were involved. These notes are from Campbell's Biology Tenth Edition Textbook.
Description: Includes my notes for Chapters 31-34 and 53 for the third exam in my class. In my case the exam was not cumulative so only those chapters were involved. These notes are from Campbell's Biology Tenth Edition Textbook.
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Lecture 21
•
Fungi
o
o
o
o
o
o
o
o
o
o
o
diverse; widespread
essential to terrestrial ecosystems
break down organic material; recycle vital nutrients
estimated 1
...
• grow as large filaments, single cells (yeasts), or both
• cell walls contain chitin
• hyphae are divided by septa
o pores allow cell to cell organelle movement
• coenocytic fungi
o lack septa
o cytoplasm is continuous
o hundreds of thousands of nuclei
• mycorrhizae
o provide phosphate ions and minerals to plants
• haustoria
o penetrate plant tissues
• most vascular plants have mutualistic mycorrhizae
• some fungi are predators
• fungi produce spores through sexual or asexual life cycles
• fungal nuclei are haploid
• brief diploid stage forms during sexual life cycles
• sexual reproduction
o fusion of hyphae from different mating types
o use pheromones to communicate their mating type
• karyogamy = nuclear fusion
• asexual reproduction
o molds
o single cell yeasts
o simple cell division
o ancestor
§ aquatic, single-celled, flagellated protist
o fungi and animals more closely related than they are to plants and eukaryotes
o oldest fossils 460 million years old
•
o symgenes
§ likely present in common ancestor to land plants
o cellulose – plant derived material
o provide digestive services to animals
Lichens
o need yeast
o on land 420 mya
Lecture 23
•
animals
o multicellular
eukaryotes
heterotrophic
o no cell walls
o nervous tissue and muscle tissue
o sexual reproduction
haploid gametes unite to produce diploid zygote
o embryonic development
mitotic divisions and development lead to adult stage
•
•
choanoflagellates may be closest living relative of animals
ediacaran biota
o 560 mya
o early members of fossil record
Cambrian explosion
o earliest fossil appearance
Paleozoic
o land impact
o vertebrates on land
Mesozoic
o first mammals
o dinosaurs
Cenozoic
o climate cooled
o mammals expanded
body plan
o radial symmetry
§ any slice makes mirror images
o bilateral symmetry
§ only one line of symmetry (lobster)
body tissues
o ectoderm – germ layer covering the embryo
o endoderm – innermost germ layer
o diploblastic animals have both layers
o triploblastic animals also have a mesoderm
body cavities
o most triploblastic animals have a body cavity (coelom)
o coelomates possess a true coelom
o pseudocoelomates
§ triploblastic with pseudocoelom
o acoelomates
§ triploblastic with no body cavity
all animals share a common ancestor
•
•
•
•
•
•
•
•
•
•
•
sponges = basal animals
eumetazoa = animals with true tissues
clade Bilateria = most animal phyla
Lecture 24
•
•
•
porifera
o sponges
o basal animals
o lack true tissues
o sedentary filter-feeders
o hermaphroditic
cnidarians
o ancient phylum of eumetazoans
o sessile and motile forms
§ jellies
§ corals
§ hydras
o diploblastic
o radial body plan
o sac with gastrovascular cavity
o single opening for mouth and anus
o diverged into 2 major clades:
§ medusozoa
• all cnidarians that produce a medusa
• scyphozoans (jellies)
• cubozoans (box jellies)
• hydrozoans
§ anthozoa
• corals
• sea anemones
• occur only as polyps
lophotrochozoans
o widest range of animal body forms
o clade identified by molecular data
o flatworms
§ phylum platyhelmithes
§ live in marine, freshwater, and damp terrestrial habitats
§ acoelomates
§ dorsoventrally flattened shape maximizes surface area for gas exchange
o rotifers
§ phylum rotifera
§ tiny animals that inhabit freshwater, the ocean, and damp soil
§ smaller than many protists
§ truly multicellular
§ specialized organ systems
o lophophorates
§ phyla ectoprocta and brachipoda
§ true coelom
§ lophophore – crown of ciliated tentacles around their mouth
•
•
•
o mollusks
§ snails and slugs (some are terrestrial)
§ oysters and clams
§ octopi and squids
§ most are marine, but some inhabit freshwater
§ soft-bodied animals; most are protected by a hard shell
§ all mollusks have a similar body plan:
• muscular foot
• visceral mass
• mantle
o annelids
§ coelomates with bodies composed of a series of flat rings
§ 2 major clades
• errantia
• sedentaria
ecdysozoans
o most species-rich animal group
o covered by a tough coat called a cuticle
o 2 large phyla:
§ nematodes
• roundworms
• found in aquatic habitats, soil, tissues of plants, and bodily fluids
and tissues of animals
• lack circulatory system
§ arthropods
• found in nearly all habitats of the biosphere
• 2 out of 3 known species of animals
• consist of 3 major lineages:
o chelicerates
§ sea spiders, horseshoe crabs, scorpions, ticks, mites,
and spiders
o myriapods
§ centipedes and millipedes
o pancrustaceans
§ lobsters, other crustaceans
§ insects
• hexapoda
o enormous clade
o insects and relatives
• live in almost every terrestrial habitat and
freshwater
echinoderms (phylum echinodermata)
o sea stars, sea urchins
chordates (phylum chordata)
o vertebrates
Lecture 25
•
chordates
o 4 key traits:
§ notochord
§ dorsal, hollow nerve chord
§ post-anal tail
§ pharyngeal slits or clefts
o 2 invertebrate groups
§ urochordates
§ cephlachordates
o all vertebrates
§ backbone
§ skeletal and nervous system help to:
• capture food
• evade predators
§ derived characters
• vertebrae enclosing a spinal chord
• elaborate skull
• fin rays (aquatic forms only)
§ gnathostomes
• vertebrates with jaws
• enlarged forebrain
• lateral line system (aquatic forms only)
• chondricthyans
o skeleton composed primarily of cartilage
o sharks, rays, skates
• tetrapods
o gnathostomes with limbs
o 4 limbs
o feet with digits
o neck
o fusion of pelvic girdle to backbone
o absence of gills (except some aquatic species)
o ears
o amphibians
§ urodela (salamanders)
§ anura (frogs)
§ apoda (caecilians)
o amniotes
§ tetrapods
§ reptiles
• scales
• lay shelled eggs
• lepidosaurs
o tuataras
o lizards
o snakes
• archosaurs
o alligators
o crocodiles
o birds
§ every reptilian feature
adapted for flight
§ mammals
• mammary glands
• hair
• high metabolic rate
• larger brain
• differentiated teeth
• primates
o lemurs
o tarsiers
o monkeys
o apes
§ humans
- upright posture
- shorter digestive tract
- larger brains
- reduced jaw bones
Lecture 26
•
•
•
ecology – the scientific study of the interactions between organisms and the environment
...
o density – the number of individuals per unit area or volume
...
§ emigration – the movement of individuals out of a population
...
§ clumped
§ uniform
§ random
o demography – the study of the vital statistics of a population and how they change
over time
...
§ survivorship curves – a graphic way of representing the data in a life table
...
Lecture 27
•
•
exponential model – describes population growth in an idealized, unlimited environment
...
+
-
deaths
-
if immigration and emigration are ignored
change in
population size
Births
=
=
births
-
bN
annual per capita
birth rate
deaths
Deaths
population size
=
mN
annual per capita
death rate
∆𝑁
∆𝑁
= 𝐵 − 𝐷
= 𝑏𝑁 − 𝑚𝑁
∆𝑡
∆𝑡
emigrants
leaving the pop
...
K>N
K
K=N
•
•
•
•
•
•
+,+
+,+
+,+
is close to 1 and the per capita rate of increase approaches
the maximum
is close to 0 and the per capita rate of increase is small
population stops growing
life history has 3 main variables:
o the age at which reproduction begins
o how often the organism reproduces
o how many offspring are produced per reproductive episode
“trade offs”
o finite resources may lead to “trade offs” between survival and reproduction
o k-selection (density dependent) – life history traits sensitive to population density
§ birth rates fall and death rates rise with population density
§ competition for resources
§ territoriality
§ disease
§ predation
§ toxic wastes
§ intrinsic factors
o r-selection (density independent) – life history traits that maximize reproduction
§ birth and death rates don’t change with population density
weather and predation population can affect population size over time
some populations undergo regular boom-and-bust cycles
crowded population + resource competition = increased emigration
metapopulations – groups of populations linked by emigration and immigration
Lecture 29
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•
•
•
•
human population
o increased slowly until 1650
o global population more than 7 billion
to maintain stability regional human population can exist in 1 of 2 configurations:
o zero population growth = high birth rate – high death rate
o zero population growth = low birth rate – low death rate
age structure – the relative number of individuals at each age
Title: Biology - Evolution and Ecology
Description: Includes my notes for Chapters 31-34 and 53 for the third exam in my class. In my case the exam was not cumulative so only those chapters were involved. These notes are from Campbell's Biology Tenth Edition Textbook.
Description: Includes my notes for Chapters 31-34 and 53 for the third exam in my class. In my case the exam was not cumulative so only those chapters were involved. These notes are from Campbell's Biology Tenth Edition Textbook.