L.4 Evolution & Genetics Flashcards
hereditary units
genes
gametes
reproductive cells
locus
gene’s location
a single organism passes on genetic information to its offspring in the form of an exact genetic copy of themselves
asexual reproduction
the offspring of asexual reproduction, genetically identical individuals
clone
two parents have an offspring with genetic variability from unique combos of genes from both parents
sexual reproduction
ordered display of chromosomes
karyotype
two identical chromosomes (same length, staining pattern, centromere position)
homologs or homologous chromosomes
X and Y chromosomes
sex chromosomes
all chromosomes except X and Y
autosomes
union of gametes, fusing their nuclei (like sperm and egg)
fertilization
diploid combo of gametes, the resulting fertilized egg
zygote
Explain the following to your friend:
“In a literal sense, children don’t inherit particular physical traits from their parents, it is the genes that are actually inherited
The physical traits derived from our genes are called phenotype. We don’t inherit phenotypes from our parents. We inherit genes and genotypes from our parents. Both of my parents have hazel eyes. I did not inherit my parents hazel eyes. Neither did any of my sisters. The reason we didn’t inherit these physical traits is because our DNA doesn’t code for the phenotype “hazel eyes”. Both my parents have the gene for brown eyes, and because of this my siblings all have brown eyes. We inherit genes that in turn determine our physical traits.
Humans have ____ chromosomes that make up ____ pairs of genes
46, 23
List the 3 different sexual life cycles and describe each
Sexual life cycles all happen by meiosis and fertilization, the timing of these things vary the life cycles between animals, plants, and fungi.
In animals, the gametes are the only haploid cells. Meiosis occurs during the production of gametes, which don’t divide anymore because they’re haploid. THen they move to fertilization, creating a diploid zygote. The zygote divides by mitosis, creating another animal.
Plants undergo alteration of generations. The original multicellular organism is called the sporophyte, and produces not gametes, but haploid spores, by meiosis. Those spores embed and divide mitoticallly to make a whole new organism, gametophyte. The gametophyte undergoes mitosis, as well, producing gametes, still haploid. These gametes fertilize, creating a diploid zygote that will develop into our sporophyte.
Fungi also produce differently. After forming a diploid zygote, meiosis occurs without producing a multicellular diploid offspring. Meiosis produces haploid cells that divide by mitosis, producing unicellar organisms or haploid multicellular organism. The haploid organism undergoes mitosis, producing gametes. The only diploid stage of fungi’s sexual life cycle is the zygote.
What 3 mechanisms of cell division contribute to genetic variability? Explain or describe each mechanism.
Independent assortment of chromosomes- chromosomes align randomly at the metaphase plate which when separated form new daughter cells that offer genetic variability.
Crossing over- two sister chromatids swap genetic information at chiasma.
Random Fertilization- in humans, each member produces about 8.4 million (2^23) different combos of our genes in our gametes, when fertilized that’s 70 trillion different possible combos (2^23x2^23). Fertilization is random. You aren’t just one in a million. You are a 1/70Trillion.
alternate versions of a gene
alleles
2 of the same alleles, either both dominant or both recessive
homozygote/homozygous
2 different alleles, dominant and recessive
heterozygote/heterozygous
the way a gene presents physically (ex: brown eyes)
phenotype
genetic make-up (ex: Bb)
genotype
family tree that describes the interrelationship of parents and children across generations
pedigree
heterozygous individuals who carry the recessive gene but are phenotypically normal
carrier
probability tool to predict offspring
Punnett squares
sum of all alleles in population
gene pool
changes in DNA
mutation
the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth
evolution
popularized evolution with his book On the Origin of Species
Charles Darwin
living things that influence an environment
biotic factors
change in an organism’s genetic makeup, DNA, that occurs through natural selection of advantageous traits for survival over an extended period of time.
Biologic Change
the organization and identification of an organism from general to specific by identifying the organisms’ Domain, Kingdom, Phylum, Class, Order, Genus, and Species
Biological classification
the analysis of body structures (body systems , skeletal systems) between two or more different species that provides insight into the genetic/biologic similarities and differences across species
Comparative anatomy
likenesses in the embryonic stage of development between different species; evidence for evolution
Embryological similarities
the complete elimination (dying out) of a species due to the species inability to survive and therefore adapt to its environment.
Extinction
Similar body structures and systems between different species; evidence for biologic evolution
Homologous Body Structures
the theory that organisms/species change over time, caused by the natural selection of advantageous traits for survival in a particular environment. This theory also proposes that all organisms evolved from a common ancestor.
Theory of Evolution
a beneficial trait that helps an organism survive in its environment
Adaptation
the characteristics that make members of the same species different from one another
Genetic Variation
explanation of how organisms in a population develop traits that allow them to survive and reproduce
Natural Selection
