Into to Life Sciences Exam 1 Flashcards

Characteristics of Animals

1. Multicellular

2. Hetertrophic

3. Cell membranes

4. Blastula stage in embryonic development

5. Mostly bodies organized into tissues

6. Mostly macroscopic

7. Mostly invertebrates

8. Mostly Marine

Phylum Porifera

Sponges

1. Nearly all marine

2. Sessile

3. Lack organs, tissues, and symmetry

4. Contain specialized cells (choanocytes and amoebocytes)

5. Suspension feeders

6. Produce sexually and asexually

Phylum Cnidaria

1. Cnide: Nettle

2. Includes

A. Jellyfish

B. Sea anemone

C. Coral polyps

3. Radial symmetry

4. No organs, but tissues

5. Sexual or sexual reproduction

Phylum Platyhelminthes

1. Flatworms

2. Simplest bilateral organisms

3. No blood circulation

4. Mostly small and aquatic

5. Reproduce asexually

Phylum Mollusca

1. Includes Gastropods, Cephalopods, and Bivalves

2. Octopi, sea slugs

3. Mollusk: soft

Phylum Annelida

1. Segmented worms

2. Annellus: ring

3. earthworms and leeches

Phylum Nematoda

1. “threadlike”

2. microscopic

3. only reproduce sexually

4. many are parasitic

Phylum Arthropoda

1. “joint foot”

2. exoskeleton

3. paired, jointed appendages

4. molting: shedding exoskeletons

5. Lobsters, scorpions, centipedes

Phylum Echinodermata

1. Spiky skin

2. Sea stars, sea urchins, sea cucumbers

3. Larvae have bilateral symmetry, adults have radial symmetry

Phylum Cordata

1. Animals with backbones!

2. Humans, dogs, cats

What is the difference between monkeys and apes?

A. Monkeys have tails, apes don’t.

B. Apes are more closely related to humans.

The Nature of Science

Purely Descriptive of the Physical world

Qualitative Data

Something that is not numerical, describes the quality of something

Quantitative Data

A Numerical description of something

Basic research

• Discovery/invention

Applied research

• innovation/application

Hypothesis

Hypothesis: a possible explanation for
an observation; can be tested by
experimentation, data collection, or
experience

A possible explanation for an observation. Can be tested by experimentation, data collection, or experience

Prediction

• Expected outcome based on the hypothesis

Limitations of the scientific process

• Cannot explain anything supernatural or faith related

• Cannot explain anything that isn’t physical

Hominins

1. More closely related to humans than chimpanzees

2. Bipedalism

3. Skull structure

4. Skeletal structure

5. Fossil footprint

6. Larger brains

What is hominin evolution? Why is it described as branching and not linear?

1. It is branching because some species lived at the same time, and often for long periods of time

Compare and contrast homo neandrethalis and homo sapiens

Homo Neandrethalis

i. Went extinct 40k years ago

ii. Not a direct ancestor of homo sapiens

iii. Larger brain but shorter than homosapiens

iv. Red hair, pale skin, type o blood

Homo sapien

i. Larger brain, including enlarged frontal lobe + enlarged cerebellum

ii. imagination, creativity, belief

iii. Survived, hominins did not

Distinguish between microevolution and macroevolution

How can reproductive isolation lead to speciation?

When animals have specific traits, they must be able to successfully breed in order for those traits to continue being present within a population. When reproduction is obstructed, those traits become specific species. Moreover, how that species breeds will impact how those traits become present in a population.

Distinguish allopatric speciation from sympatric speciation

What are the two major models for the timing of speciation?

How do mass extinctions lead to increased speciation?

Microevolution

A. Change of allele frequencies in a population

B. Still the same species, just looks/behaves differently

Macroevolution

Change from one species to another

What are the different kinds of species concepts?

A. Morphological

B. Phylogenetic

C. Biological

Morphological

A. Based on physical traits

i. weakness: very subjective

Phylogenetic

A. Smallest group of individuals that share a common ancestor

i. weakness: how much difference is required to be another species?

Biological

Ernst Mayr, 1942

A. Most widely accepted

B. Group of successfully interbreeding organisms

C. Weaknesses

i. interspecific hybridization

ii. uncertainty of geographically separated populations

iii. asexual reproduction

iv. fossils can’t be tested

Allopatric speciation

A. “other fatherland”

B. Geographic isolation leads to speciation

C. Gene pool of a population can be changed by

i. natural selection

ii. mutation

iii. genetic drift

Adaptive radiation

A. rapid emergence of may species from a single species that has been introduced to a new environment

B. Islands provide great examples

Sympatric Speciation

A. “same fatherland”

B. Occurs within the same geographic area

C. polyploidy in plants, sexual selection

How does speciation occur?

A. Reproductive barriers

i. isolates the gene pools of species

ii. prevents interbreeding

Prezygotic speciation barriers

A. Before fertilization

i. habitat isolation, separated geographically

ii. temporal isolation, breeding at different times

iii. behavioral isolation, different courtship rituals

iv. mechanical isolation: reproductive parts are not compatible

v. gametic isolation: gametes not compatible

postzygotic barriers

i. reduced hybrid vitality: short-lived, sterile, sterile offspring

Types of speciation models

Gradual: changes slowly

Punctuated: changes quickly

extinction and diversification

A. Diversity follows extinction, allows things to regenerate

Population

all the members of a species in a given location

genetic variation

differences in DNA sequences between organisms

sources of genetic variation

a. sexual reproduction

i. meiosis

ii. random fertilization

natural selection

A. the best traits of a population get passed down

three modes of natural selection

i. stabilizing: both of the extremes of a population are targeted (usually by predators) and do not survive.

ii. directional: one extreme of a population is targeted.

iii. disruptive: the median of a population is targeted

genetic drift

a. chance alteration in frequency of a gene variant in a population

i. bottleneck effect: only a few variants of a species survive. the effects on alleles is represented in today’s population

i. founder effect: a small group becomes isolated. interbreeding with each other, the same alleles become present in the population.

gene flow

the movement of genes from one population to another

i. migration

ii. pollination

mutations

a. a change in DNA resulting in new genetic variation

nonrandom mating

a. choosers can be picky!

i. assortative mating

ii. sexual selection

hardy-Weinberg equilibrium

a. shows how much change occurs in a population

i. shows what random mating would look like, so people can contrast with the mating that is actually occuring

key points about natural selection

i. natural selection is the only mechanism that consistently leads to adaptive evolution

ii. individuals do not evolve, populations evolve

iii. natural selection cannot create new traits

iv. adaptations can be compromises

v. evolution does not result in perfection