Classwork Questions and vocab (bio - unit 2)

meaning of “descent with modification”

organisms inherit traits from their ancestors, but those traits change over generations, causing species to evolve over time

3 key points about evolution by natural selection

1. populations evolve, not individuals

2. natural selection only effects heritable traits (in genetic code)

3. doesn’t lead to perfectly adapted species

for how many millions of years have we been the only living member of our genus?

0.04 million years (40,000 years)

which hominin species coexisted 1.7 million years ago?

• P.boisei

• P. robustus

• H. habilis

• H. ergaster

• H. erectus

transitional forms

the fossil record includes intermediate forms of organisms that show sequential adaptations to a habitat

what two features do all vertebrate embryos show at early developmental stages, despite these not being visible to us in our adult form?

1. post-anal tails

2. pharyngeal (throat) arches

which term describes the study of fossils and was developed largely by Georges Cuvier?

paleontology

what statement is evidence that all tetrapods shared a single common ancestor?

all tetrapod limbs have a common pattern of one bone, two bones, many bones, then digits

how have we created superbugs?

natural selection for antibiotic resistance is strong because of our extensive use/misuse of antibiotics

humans owe much of their physical versatility and athleticism to their flexible joints/limbs. but we are prone to sprains, torn ligaments, and dislocations. why?

adaptions are often compromises. stressing limits of that "good enough" trait causes sprains, torn ligaments, and dislocations

which is the “flexor” muscle?

bicep

which is the “extensor” muscle

tricep

speciation

the process by which one species evolves into two or more new species through genetic changes and reproductive isolation over time

homologies/homologic structures

body parts in different species that have a similar underlying structure because they were inherited from a common ancestor, even if they have different functions

reasons for reduced gene flow/reproduction

• geographic barriers

• different mating behaviors (songs/calls, mutations, breeding seasons, incompatible reproductive structures)

reproductive isolation

no more fertile offspring being able to be produced

timeline: evolution of a cell

1. prokaryotes

2. cyanobacterium

3. aerobic bacteria

4. heterotrophic bacteria

5. autotrophic bacteria

differences between animal and plant cell: animal cells

• lysosomes

• centrosomes

• vacuole - small (+ numerous sometimes)

• round in shape

• microvilli

• cillia/flagella

differences between animal and plant cell: plant cells

• has cell wall

• cell membrane

• vacuole - bigger

• chloroplasts (green)

• boxy in shape

• plasmodesmata

• cellulose

transitional fossil

a fossil that shows traits of both an ancestral species and a more recently evolved species, providing evidence of evolutionary change over time

node

the point on a phylogenetic tree where one ancestral lineage splits into two or more descendant lineages, representing a common ancestor

allele frequency

the proportion of a specific version of a gene (allele) in a population compared with all versions of that gene

evolution

the change in the inherited traits and allele frequencies of a population over generations

biodiversity

the variety of living organisms, including the diversity of genes, species, and ecosystems in an area or on earth

outgroup

a species or group that is closely related to, but not part of, the group being studied and is used as a comparison when building a phylogenetic tree

selective pressure

an environmental factor that affects an organism's ability to survive and reproduce, favoring certain traits over others

polyploidy

the condition in which an organism has more than two complete sets of chromosomes, often leading to the formation of a new species in plants

cladogram

a branching diagram that shows the evolutionary relationships among organisms based on shared derived characteristics

analogous structure

body parts in different species that have similar functions but evolved independently and do not share a common ancestral structure

cartilage

a smooth, firm, flexible connective tissue that is usually white or bluish-white and has a shiny appearance, supporting parts of the body and cushioning joints

tendon

a tough, strong, fibrous connective tissue that is white, shiny, and slightly cord-like, connecting muscles to bones

derived character

a trait that evolved in a common ancestor and is shared by its descendants but was not present in earlier ancestors

naturalist

a scientist who studies organisms and the natural world by observing, describing, and classifying living things and their environments