Lecture 7, 8/9 Flashcards
What are animal bodies distinguished by
- a tube within a tube
What does a tube within a tube mean?
-inner tube = gut
-food enters in entrance and ingested food passes to the exit
- gut lies inside larger cylinder which houses all the other stuff
about how many phyla in animal kingdom and what does it mean?
30
- own body plan that somehow varies the basic plan
- lifeforms sharing more of the pathway to LUCA = closer related and share more features
What is the Cambrian explosion?
all the living animal phyla appear in the fossil record in a relatively short time span
- explosion of many new forms
- Cambrian = geological layer in which located
Which life cycles are less varied plants or animals?
animals
what kingdom is closest to animals?
Choanoflagellates
- fungi = not primitive plants
how many vertebrate lineages are there
7
how many lineages of fish are there?
6
What are the phyla most closely related to chordates?
- hemichordate
- xenoturbellida
- echinodermata
within the chordates who are humans closes relatives?
Tunicates
- evolution of skeleton is different (spinal cord and large brain = humans unique)
What are the closest living twigs to hominids
2 chimpanzee species
Did humans evolve from chimps?
No, we just share with chimps an ancestor who lived about 7 mya
What does protostomes and deuterostomes mean?
protostomes = first mouth
deuterostomes = second mouth
means how does gut develop
What are two characteristics of lophotrochozoans
- Lophophores function in suspension feeding in adults…
- Trochophore larvae swim and may feed
All three lineages of chordates are defined by the presence of four features
- Pharyngeal slits or pouches
- Dorsal hollow nerve cord
- Notochord
- Muscular, post anal tail
Who is the father of genetics
Gregor mendel
What is selective breeding
- offspring resembled parents
- improve animal and plant varieties 19th century
What was Mendel trying to do
improve taste, flavour, yield of peas
what are genes and what do they do
- molecules
- code for mRNA molecules (transcription), which make proteins (translation), do work of building and running cell
- central dogma
Where are genes located
on the chromosomes
What is the cell cycle
- interval between cell divisions
- mostly growth and replication)
what is mitosis
- replication division
- 2 cells identical to parent
what is meiosis
- reduction division
- diploid -> haploid
What is a locus
a particular place on a chromosome that any given gene is located in
What are alleles
varieties of each gene
What are homologous pairs?
a single chromosome pair one from dad and one from mom
What is a tetrad
each homologue replicated to be 2 sister chromatids
What are Mendel’s laws and what does it mean
- segregation
- Independent Assortment
- any of the possible combos of chromosomes from dad and mom is possible in any of the gametes
What is phenotype
outward appearance
what is genotype
actual genetic makeup
what is epigenetic
heritable changes in gene function that do not involve changes in DNA sequence
Is the expression of a trait always binomial?
no, some vary continuously depending on just which combo of alleles an individual has inherited
What is the Hardy Weinberg equilibrium
any distribution of allele frequencies will quickly arrive at an equilibrium distribution
What are allele frequencies
frequency (the proportion of the total present) of each allele type in the population/gene pool
What is the importance of HWE
show that with a set of assumptions the allele frequency distribution quickly settles down to an equilibrium and shows no change over successive generations
What are the assumptions of HWE/ what are the only ways in which allele frequencies change?
Gene flow = individuals move in or out of the population, carrying genes with them
Genetic drift = the population is small enough that chance events can alter allele frequencies
Non random mating = some mating combinations are somehow more likely than others
Mutations = the spontaneous alteration of some alleles into others, the background rate is low enough that this is rarely a concern
Natural selection = allele frequencies will change if some alleles contribute to better survival or more reproduction of the individuals that carry them than others…
